We Keep Coding

Panel.Controls.Remove not deleting all the controls It should(.NET)

I'm making a database manager program and the program creates only as much textbox
as needed (counts the columns in the table). But for some reason the program is not removing all the textboxes I want.
New textboxes should be created and old ones should be removed on every "ComboBoxSelectedIndexChange".
Here is my code snippet:
var elm = panel20.Controls.OfType<System.Windows.Forms.TextBox>();
foreach (var item in elm)
{
DeleteControlsWithTag(item.Tag.ToString());
}
button19.Enabled = true;
one_cond = string.Empty;
if (comboBox19.Text != string.Empty)
{
one_cond = comboBox19.Text.ToUpper();
if (one_cond == "ÖSSZES")
{
string allcolumn = "(";
colnames.Remove("Összes");
for (int i = 0; i < colnames.Count - 1; i++)
{
allcolumn += colnames.ElementAt(i) + ",";
}
allcolumn += colnames.Last() + ")";
button19.Enabled = false;
textBox16.Text = ManualQuery + " " + from + " " + allcolumn + " " + "VALUES" + " ";
if (3 < colnames.Count)
{
for (int i = 0; i < colnames.Count; i++)
{
System.Windows.Forms.TextBox textbox = new System.Windows.Forms.TextBox();
textbox.Name = $"textbox_{i}";
textbox.AccessibleName = $"textbox_{i}";
textbox.Tag = $"textbox_{i}";
panel20.Controls.Add(textbox);
textbox.Parent = panel20;
//"textbox_" + colnames[i] + i
if (2<i)
{
if (i == 3)
{
textbox.Location = new System.Drawing.Point(489, 49);
}
else
{
textbox.Location = new System.Drawing.Point(489 + ((i - 3) * 71), 49);
}
}
else
{
if (0 < i)
{
textbox.Location = new System.Drawing.Point(467 + (i * 71), 17);
}
else
{
textbox.Location = new System.Drawing.Point(467, 17);
}
}
textbox.Size = new System.Drawing.Size(64, 20);
}
}
else
{
for (int i = 0; i < colnames.Count; i++)
{
System.Windows.Forms.TextBox textbox = new System.Windows.Forms.TextBox();
textbox.Name = $"textbox_{i}";
textbox.AccessibleName = $"textbox_{i}";
textbox.Parent = panel20;
panel20.Controls.Add(textbox);
textbox.Tag = $"textbox_{i}";
if (0<i)
{
textbox.Location = new System.Drawing.Point(467 + (i*71), 17);
}
else
{
textbox.Location = new System.Drawing.Point(467, 17);
}
textbox.Size = new System.Drawing.Size(64, 20);
}
}
}
else
{
onecondinsert = "(" + one_cond + ")";
textBox16.Text = ManualQuery + " " + from + " " + onecondinsert + " " + "VALUES" + " ";
System.Windows.Forms.TextBox textbox = new System.Windows.Forms.TextBox();
textbox.Name = $"textbox";
textbox.AccessibleName = $"textbox";
textbox.Location = new System.Drawing.Point(464, 20);
textbox.Size = new System.Drawing.Size(100, 20);
textbox.Parent = panel20;
textbox.Tag = "textbox";
panel20.Controls.Add(textbox);
//tbox.TextChanged += tbox_TextChanged;
}
}
MessageBox.Show(elm.Count().ToString());
}
and here is some screenshot of how the problem looks like
on the first select it works
on this picture you can see the program did not delete all the text box.
longer textbox is the new one
On the third picture I selected another column (only one textbox should be visible) but the program deletes one textbox
as you can see here
After the third selection it deletes the last extra textbox too
3. try it "works"
I have tried different ways to delete from the panel20.controls
but all produced the same bug
Hope someone can help me, Thanks
Update:
I tried another method from here:
C#, deleting all the controls with the same .Tag
private List<Control> GetTaggedControls(string tag, Control parent)
{
var taggedControls = new List<Control>();
foreach (Control control in parent.Controls)
{
if (control.Tag?.ToString() == tag)
{
taggedControls.Add(control);
}
// Recursively call this method in case this is a container
taggedControls.AddRange(GetTaggedControls(tag, control));
}
return taggedControls;
}
// Deletes all controls with the specified tag
private void DeleteControlsWithTag(string tag)
{
foreach (Control control in GetTaggedControls(tag, this))
{
panel20.Controls.Remove(control);
}
}
and I tried to delete the textboxes like this:
var elm = panel20.Controls.OfType<System.Windows.Forms.TextBox>();
foreach (var item in elm)
{
DeleteControlsWithTag(item.Tag.ToString());
}
but it is still not working

Your GetTaggedControls() function is finding ANY type of control, RECURSIVELY starting at the main Form container level, that has a specific tag. So returned controls might not be from many containers, but your DeleteControlsWithTag() method tries to remove all matches only from panel20. That may or may not be a problem; it's unclear from the pictures and possibly incomplete posted code.
When you say remove the old textboxes, can we simply remove ALL existing TextBoxes, or do you really need to match tags?
From your original attempt:
var elm = panel20.Controls.OfType<System.Windows.Forms.TextBox>();
foreach (var item in elm)
{
DeleteControlsWithTag(item.Tag.ToString());
}
This is finding ALL textboxes in panel20, then trying to delete them based on matching tags with the helper function. So the tag doesn't even matter since you are finding all textboxes to begin with...
Just try removing all TextBoxes from panel20?
var elm = panel20.Controls.OfType<System.Windows.Forms.TextBox>().ToList();
elm.ForEach(tb => panel20.Controls.Remove(tb));

Okay, now I tried to tie together Idle_Mind's and LarsTech's recommendation
and finally it's working fine with "Dispose".
Thanks guys for your quick help.
here is the previous code:
var elm = panel20.Controls.OfType<System.Windows.Forms.TextBox>();
foreach (var item in elm)
{
DeleteControlsWithTag(item.Tag.ToString());
}
and here is the new one:
var elm = panel20.Controls.OfType<System.Windows.Forms.TextBox>().ToList();
elm.ForEach(tb => tb.Dispose());

CheckBoxList In GridView Only Remember The First Option Ticked When New Row Added

I have a grid view with multiple columns which allow user to fill in the data and they are able to add a new row after finishing filling the data. Among the columns, there is a column with CheckBoxList which I allow user to multiple select the option on the CheckBoxList but every time add a new row, only the first option select by the user is remain while other selection is gone. How am I able to let the option selected by the user remain while I add a new row?
private void SetPreviousDataLecturer()
{
int rowIndex = 0;
if (ViewState["LecturerGridView"] != null)
{
DataTable dataTableCurrent = (DataTable)ViewState["LecturerGridView"];
if (dataTableCurrent.Rows.Count > 0)
{
for (int i = 0; i < dataTableCurrent.Rows.Count; i++)
{
TextBox textBoxLName = (TextBox)LecturerGridView.Rows[rowIndex].Cells[1].FindControl("LecturerName");
TextBox textBoxLID = (TextBox)LecturerGridView.Rows[rowIndex].Cells[2].FindControl("LecturerID");
TextBox textBoxLAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[3].FindControl("LecturerAddress");
TextBox textBoxLPNumber = (TextBox)LecturerGridView.Rows[rowIndex].Cells[4].FindControl("LecturerPNumber");
TextBox textBoxLEAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[5].FindControl("LecturerEAddress");
CheckBoxList checkBoxListLCourse = (CheckBoxList)LecturerGridView.Rows[rowIndex].Cells[6].FindControl("LecturerCourse");
TextBox textBoxLPassword = (TextBox)LecturerGridView.Rows[rowIndex].Cells[7].FindControl("LecturerPassword");
LecturerGridView.Rows[i].Cells[0].Text = Convert.ToString(i + 1);
textBoxLName.Text = dataTableCurrent.Rows[i]["LecturerName"].ToString();
textBoxLID.Text = dataTableCurrent.Rows[i]["LecturerID"].ToString();
textBoxLAdd.Text = dataTableCurrent.Rows[i]["LecturerAddress"].ToString();
textBoxLPNumber.Text = dataTableCurrent.Rows[i]["LecturerPNumber"].ToString();
textBoxLEAdd.Text = dataTableCurrent.Rows[i]["LecturerEAddress"].ToString();
checkBoxListLCourse.SelectedValue = dataTableCurrent.Rows[i]["LecturerCourse"].ToString();
textBoxLPassword.Text = dataTableCurrent.Rows[i]["LecturerPassword"].ToString();
rowIndex++;
}
}
}
}
private void AddNewRowToLecturerGV()
{
int rowIndex = 0;
if (ViewState["LecturerGridView"] != null)
{
DataTable dataTableCurrent = (DataTable)ViewState["LecturerGridView"];
DataRow dataRowCurrent = null;
if (dataTableCurrent.Rows.Count > 0)
{
for (int i = 1; i <= dataTableCurrent.Rows.Count; i++)
{
TextBox textBoxLName = (TextBox)LecturerGridView.Rows[rowIndex].Cells[1].FindControl("LecturerName");
TextBox textBoxLID = (TextBox)LecturerGridView.Rows[rowIndex].Cells[2].FindControl("LecturerID");
TextBox textBoxLAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[3].FindControl("LecturerAddress");
TextBox textBoxLPNumber = (TextBox)LecturerGridView.Rows[rowIndex].Cells[4].FindControl("LecturerPNumber");
TextBox textBoxLEAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[5].FindControl("LecturerEAddress");
CheckBoxList checkBoxListLCourse = (CheckBoxList)LecturerGridView.Rows[rowIndex].Cells[6].FindControl("LecturerCourse");
TextBox textBoxLPassword = (TextBox)LecturerGridView.Rows[rowIndex].Cells[7].FindControl("LecturerPassword");
dataRowCurrent = dataTableCurrent.NewRow();
dataRowCurrent["RowNumber"] = i + 1;
dataTableCurrent.Rows[i - 1]["LecturerName"] = textBoxLName.Text;
dataTableCurrent.Rows[i - 1]["LecturerID"] = textBoxLID.Text;
dataTableCurrent.Rows[i - 1]["LecturerAddress"] = textBoxLAdd.Text;
dataTableCurrent.Rows[i - 1]["LecturerPNumber"] = textBoxLPNumber.Text;
dataTableCurrent.Rows[i - 1]["LecturerEAddress"] = textBoxLEAdd.Text;
dataTableCurrent.Rows[i - 1]["LecturerCourse"] = checkBoxListLCourse.SelectedValue.ToString();
dataTableCurrent.Rows[i - 1]["LecturerPassword"] = textBoxLPassword.Text;
rowIndex++;
}
dataTableCurrent.Rows.Add(dataRowCurrent);
ViewState["LecturerGridView"] = dataTableCurrent;
LecturerGridView.DataSource = dataTableCurrent;
LecturerGridView.DataBind();
}
}
else
{
Response.Write("ViewState is null.");
}
SetPreviousDataLecturer();
}

You need to maintain state for selected checkbox. On the button click 'Add new row' first get the state of each rows in a DataTable and add a blank row then populate that DataTable.
You need to maintain checkbox's selected item's state also. You can get selected values in a CSV as :
string selectedItems = String.Join(",",
checkBoxListLCourse.Items.OfType<ListItem>().Where(r => r.Selected)
.Select(r => r.Value));
and you can restore as :
string[] items = selectedItems.Split(',');
for (int i = 0; i < checkBoxListLCourse.Items.Count; i++)
{
if (items.Contains(checkBoxListLCourse.Items[i].Value))
{
checkBoxListLCourse.Items[i].Selected = true;
}
}

My answer. This answer has some problem like the checkbox list will automatically scroll to the most top when we tick on anything in the checkbox list.
private void SetPreviousDataLecturer()
{
int rowIndex = 0;
if (ViewState["LecturerGridView"] != null)
{
DataTable dataTableCurrent = (DataTable)ViewState["LecturerGridView"];
if (dataTableCurrent.Rows.Count > 0)
{
for (int i = 0; i < dataTableCurrent.Rows.Count; i++)
{
TextBox textBoxLName = (TextBox)LecturerGridView.Rows[rowIndex].Cells[1].FindControl("LecturerName");
TextBox textBoxLID = (TextBox)LecturerGridView.Rows[rowIndex].Cells[2].FindControl("LecturerID");
TextBox textBoxLAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[3].FindControl("LecturerAddress");
TextBox textBoxLPNumber = (TextBox)LecturerGridView.Rows[rowIndex].Cells[4].FindControl("LecturerPNumber");
TextBox textBoxLEAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[5].FindControl("LecturerEAddress");
CheckBoxList checkBoxListLCourse = (CheckBoxList)LecturerGridView.Rows[rowIndex].Cells[6].FindControl("LecturerCourse");
TextBox textBoxLPassword = (TextBox)LecturerGridView.Rows[rowIndex].Cells[7].FindControl("LecturerPassword");
LecturerGridView.Rows[i].Cells[0].Text = Convert.ToString(i + 1);
textBoxLName.Text = dataTableCurrent.Rows[i]["LecturerName"].ToString();
textBoxLID.Text = dataTableCurrent.Rows[i]["LecturerID"].ToString();
textBoxLAdd.Text = dataTableCurrent.Rows[i]["LecturerAddress"].ToString();
textBoxLPNumber.Text = dataTableCurrent.Rows[i]["LecturerPNumber"].ToString();
textBoxLEAdd.Text = dataTableCurrent.Rows[i]["LecturerEAddress"].ToString();
checkBoxListLCourse.Text = dataTableCurrent.Rows[i]["LecturerCourse"].ToString();
string lecturerCourse = dataTableCurrent.Rows[i]["LecturerCourse"].ToString();
if (!string.IsNullOrEmpty(lecturerCourse))
{
for (int j = 0; j < lecturerCourse.Split(',').Length; j++)
{
checkBoxListLCourse.Items.FindByValue(lecturerCourse.Split(',')[j].ToString()).Selected = true;
}
}
textBoxLPassword.Text = dataTableCurrent.Rows[i]["LecturerPassword"].ToString();
rowIndex++;
}
}
}
}
private void AddNewRowToLecturerGV()
{
int rowIndex = 0;
if (ViewState["LecturerGridView"] != null)
{
DataTable dataTableCurrent = (DataTable)ViewState["LecturerGridView"];
DataRow dataRowCurrent = null;
if (dataTableCurrent.Rows.Count > 0)
{
for (int i = 1; i <= dataTableCurrent.Rows.Count; i++)
{
TextBox textBoxLName = (TextBox)LecturerGridView.Rows[rowIndex].Cells[1].FindControl("LecturerName");
TextBox textBoxLID = (TextBox)LecturerGridView.Rows[rowIndex].Cells[2].FindControl("LecturerID");
TextBox textBoxLAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[3].FindControl("LecturerAddress");
TextBox textBoxLPNumber = (TextBox)LecturerGridView.Rows[rowIndex].Cells[4].FindControl("LecturerPNumber");
TextBox textBoxLEAdd = (TextBox)LecturerGridView.Rows[rowIndex].Cells[5].FindControl("LecturerEAddress");
CheckBoxList checkBoxListLCourse = (CheckBoxList)LecturerGridView.Rows[rowIndex].Cells[6].FindControl("LecturerCourse");
TextBox textBoxLPassword = (TextBox)LecturerGridView.Rows[rowIndex].Cells[7].FindControl("LecturerPassword");
dataRowCurrent = dataTableCurrent.NewRow();
dataRowCurrent["RowNumber"] = i + 1;
dataTableCurrent.Rows[i - 1]["LecturerName"] = textBoxLName.Text;
dataTableCurrent.Rows[i - 1]["LecturerID"] = textBoxLID.Text;
dataTableCurrent.Rows[i - 1]["LecturerAddress"] = textBoxLAdd.Text;
dataTableCurrent.Rows[i - 1]["LecturerPNumber"] = textBoxLPNumber.Text;
dataTableCurrent.Rows[i - 1]["LecturerEAddress"] = textBoxLEAdd.Text;
string lecturerCourse = string.Empty;
foreach (ListItem item in checkBoxListLCourse.Items)
{
if (item.Selected)
{
if (!string.IsNullOrEmpty(lecturerCourse))
{
lecturerCourse += ",";
}
lecturerCourse += item.Value;
}
}
dataTableCurrent.Rows[i - 1]["LecturerCourse"] = lecturerCourse;
dataTableCurrent.Rows[i - 1]["LecturerPassword"] = textBoxLPassword.Text;
rowIndex++;
}
dataTableCurrent.Rows.Add(dataRowCurrent);
ViewState["LecturerGridView"] = dataTableCurrent;
LecturerGridView.DataSource = dataTableCurrent;
LecturerGridView.DataBind();
}
}
else
{
Response.Write("ViewState is null.");
}
SetPreviousDataLecturer();
}

Re-loading Dynamic RadioButtonList on postback

I am creating an application where different kinds of survey questions are pulled from a database.
The first kind I am implementing is a list of questions each with four radio buttons to choose from.
My code for creating the radio button lists and mark up dynamically is
protected void ProcessData(DataTable question, DataTable answers)
{
int i = 0;
foreach (DataRow row in question.Rows)
{
HtmlGenericControl rowDiv = new HtmlGenericControl("div");
rowDiv.Attributes["class"] = "classRowDiv";
panel1.Controls.Add(rowDiv);
HtmlGenericControl questionDiv = new HtmlGenericControl("div");
questionDiv.Attributes["class"] = "classQuestionDiv";
questionDiv.ID = "questionDiv" + i.ToString();
rowDiv.Controls.Add(questionDiv);
Label questionLabel = new Label();
questionLabel.Attributes["class"] = "classQuestionLabelDiv";
if (row[2].ToString() == "Radio button")
{
questionLabel.Text = row[3].ToString();
rowDiv.Controls.Add(questionLabel);
HtmlGenericControl radioDiv = new HtmlGenericControl("div");
radioDiv.Attributes["class"] = "classRadioDiv";
radioDiv.ID = "radioDiv" + i.ToString();
rowDiv.Controls.Add(radioDiv);
RadioButtonList rbl = new RadioButtonList();
rbl.ID = "List" + i.ToString();
radioDiv.Controls.Add(rbl);
rbl.RepeatDirection = RepeatDirection.Horizontal;
Label lbl = new Label();
lbl.Text = "<hr />";
panel1.Controls.Add(lbl);
DataRow rowA;
for (int j = 0; j < 4; j++ )
{
rowA = answers.Rows[j];
ListItem button = new ListItem(rowA[2].ToString(), j.ToString());
button.Attributes["class"] = "radioStyle";
rbl.Items.Add(button);
}
i++;
}
}
}
The problem I am having is actually getting the selected values of the buttons. I have come to understand from reading around that dynamically created controls must be re-loaded with the same ID after a postback but I do not fully understand how to achieve this as the amount of radio buttons created is dependent on the result set from the database.

how to get the value of dynamically populated controls

I have a div Conatining a Panel in aspx page
<div id="divNameofParticipants" runat="server">
<asp:Panel ID="panelNameofParticipants" runat="server">
</asp:Panel>
</div>
I am populating the panel dynamically from codebehind with the following code:
void btnSubmitCountParticipant_Click(object sender, EventArgs e)
{
StringBuilder sbparticipantName=new StringBuilder();
try
{
int numberofparticipants = Convert.ToInt32(drpNoofparticipants.SelectedValue);
ViewState["numberofparticipants"] = numberofparticipants;
Table tableparticipantName = new Table();
int rowcount = 1;
int columnCount = numberofparticipants;
for (int i = 0; i < rowcount; i++)
{
TableRow row = new TableRow();
for (int j = 0; j < columnCount; j++)
{
TableCell cell = new TableCell();
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "txtNameofParticipant" + Convert.ToString(i);
cell.ID = "cell" + Convert.ToString(i);
cell.Controls.Add(txtNameofParticipant);
row.Cells.Add(cell);
}
tableparticipantName.Rows.Add(row);
panelNameofParticipants.Controls.Add(tableparticipantName);
}
}
catch(Exception ex)
{
}
}
Now I want to access the value of these dynamically generated textbox in the codebehind.for which i my code is as under:
public void CreateControls()
{
try
{
//String test1 = test.Value;
List<string> listParticipantName = new List<string>();
if (ViewState["numberofparticipants"] != null)
{
int numberofparticipants = Convert.ToInt32(ViewState["numberofparticipants"]);
for (int i = 0; i < numberofparticipants; i++)
{
string findcontrol = "txtNameofParticipant" + i;
TextBox txtParticipantName = (TextBox)panelNameofParticipants.FindControl(findcontrol);
listParticipantName.Add(txtParticipantName.Text);
}
}
}
catch (Exception ex)
{
}
}
but I am not able to get the values in codebehind.
TextBox txtParticipantName = (TextBox)panelNameofParticipants.FindControl(findcontrol);
the above code is not able to find the control and its always giving null.what am i doing wrong.i recreated the controls in page load also since postback is stateless but still no success.
Thanks in Advance

You need to create dynamic controls in PreInit not in OnLoad. See documentation here: https://msdn.microsoft.com/en-us/library/ms178472.aspx
Re/Creating the controls on page load will cause the ViewState not to be bound to the controls because viewstate binding happens before OnLoad.

As mentioned by other people. To create dynamic controls your need to do this for every postback and at the right time. To render dynamic controls, use the Preinit event. I suggest that your have a look at https://msdn.microsoft.com/en-us/library/ms178472(v=vs.80).aspx to learn more about this.
MSDN - PreInit:
Use this event for the following:
Check the IsPostBack property to determine whether this is the first time the page is being processed.
Create or re-create dynamic controls.
Set a master page dynamically.
Set the Theme property dynamically.
Read or set profile property values.
NoteNote If the request is a postback, the values of the controls have not yet been restored from view state. If you set a control property at this stage, its value might be overwritten in the next event.
The next interesting event is Preload that states:
MSDN - PreLoad
Use this event if you need to perform processing on your page or control before the Load event.
After the Page raises this event, it loads view state for itself and all controls, and then processes any postback data included with the Request instance.
Meaning that in the next event Load (Page_Load) the viewstate should be loaded, so here you should effectively be able to check your values.
You also need to make sure that view state is enabled and the easiest is probably in the page level directive:
<%#Page EnableViewState="True" %>
Take a look at the article https://msdn.microsoft.com/en-us/library/ms972976.aspx2 that goes more into the depth of all this
Note
If your problem is that you need to create controls dynamically on a button click, and there will be many controls created, you should probably turn to jQuery ajax and use the attribute [WebMethod] on a public function in your code behind. Creating dynamic controls and maintaining the ViewState is quite costly, so i really recommend this, for a better user experience.

If you use a DataPresentation control like asp:GridView it will be much easier.
Markup
<asp:GridView ID="ParticipantsGrid" runat="server" AutoGenerateColumns="false">
<Columns>
<asp:TemplateField HeaderText="Participants">
<ItemTemplate>
<asp:TextBox ID="txtNameofParticipant" runat="server"
Text='<%# Container.DataItem %>'>
</asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Code-behind
protected void btnSubmitCountParticipant_Click(object sender, EventArgs e)
{
try
{
var selectedParticipantCount = Convert.ToInt32(drpNoofparticipants.SelectedValue);
var items = Enumerable.Repeat(string.Empty, selectedParticipantCount).ToList();
ParticipantsGrid.DataSource = items;
ParticipantsGrid.DataBind();
}
catch (Exception ex)
{ }
}
public void CreateControls()
{
try
{
var participants = ParticipantsGrid.Rows
.Cast<GridViewRow>()
.Select(row => ((TextBox)row.FindControl("txtNameofParticipant")).Text)
.ToList();
}
catch (Exception ex)
{ }
}

I think you are doing that correctly. In asp.net webforms, there are lots of times that you will experienced strange things that are happening. Especially with the presence of ViewState. First we need to troubleshoot our code and try different tests and approaches. That will be my advise for you, pleas use this code and debug if what is really happening:
void btnSubmitCountParticipant_Click(object sender, EventArgs e)
{
StringBuilder sbparticipantName=new StringBuilder();
try
{
int numberofparticipants = Convert.ToInt32(drpNoofparticipants.SelectedValue);
ViewState["numberofparticipants"] = numberofparticipants;
Table tableparticipantName = new Table();
int rowcount = 1;
int columnCount = numberofparticipants;
TableRow row = new TableRow();
TableCell cell = new TableCell();
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "NameTest";
txtNameofParticipant.Text = "This is a textbox";
cell.ID = "cellTest";
cell.Controls.Add(txtNameofParticipant);
row.Cells.Add(cell);
tableparticipantName.Rows.Add(row);
panelNameofParticipants.Controls.Add(tableparticipantName);
}
catch(Exception ex)
{ // please put a breakpoint here, so that we'll know if something occurs,
}
}
public void CreateControls()
{
try
{
//String test1 = test.Value;
List<string> listParticipantName = new List<string>();
//if (ViewState["numberofparticipants"] != null)
//{
string findcontrol = "NameTest";
TextBox txtParticipantName = (TextBox)panelNameofParticipants.Controls["NameText"];
//check if get what we want.
listParticipantName.Add(txtParticipantName.Text);
//}
}
catch (Exception ex)
{// please put a breakpoint here, so that we'll know if something occurs,
}
}

Dynamic controls need to be recreated on every post-back. The easiest way to achieve that in your code would be to cache the control structure and repopulate it. This how it can be done:
void btnSubmitCountParticipant_Click(object sender, EventArgs e)
{
StringBuilder sbparticipantName=new StringBuilder();
Panel p1 = new Panel();
try
{
int numberofparticipants = Convert.ToInt32(drpNoofparticipants.SelectedValue);
ViewState["numberofparticipants"] = numberofparticipants;
Table tableparticipantName = new Table();
int rowcount = 1;
int columnCount = numberofparticipants;
for (int i = 0; i < rowcount; i++)
{
TableRow row = new TableRow();
for (int j = 0; j < columnCount; j++)
{
TableCell cell = new TableCell();
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "txtNameofParticipant" + Convert.ToString(i);
cell.ID = "cell" + Convert.ToString(i);
cell.Controls.Add(txtNameofParticipant);
row.Cells.Add(cell);
}
tableparticipantName.Rows.Add(row);
p1.Controls.Add(tableparticipantName);
}
Cache["TempPanel"] = p1;
panelNameofParticipants.Controls.Add(p1);
}
catch(Exception ex)
{
}
}
Look for the p1 panel in the above code to see the changes. Now the code for the CreateControls function need to be changed as following:
public void CreateControls()
{
try
{
Panel p1= (Panel)Cache["TempPanel"];
panelNameofParticipants.Controls.Add(p1);
//String test1 = test.Value;
List<string> listParticipantName = new List<string>();
if (ViewState["numberofparticipants"] != null)
{
int numberofparticipants = Convert.ToInt32(ViewState["numberofparticipants"]);
for (int i = 0; i < numberofparticipants; i++)
{
string findcontrol = "txtNameofParticipant" + i;
TextBox txtParticipantName = (TextBox)panelNameofParticipants.FindControl(findcontrol);
listParticipantName.Add(txtParticipantName.Text);
}
}
}
catch (Exception ex)
{
}
}
Hope this helps.

Dynamically created controls would disappear when page posts back, This article here explains why it happens.
So in order to make dynamic controls be recognized by asp.net page, you need to recreate it in preinit event handler, but I think it is difficult as this dynamic controls in your case rely on some other web form element such as a dropdownlist drpNoofparticipants and also ViewState is not available at this stage.
My suggestion is that we do it in a different way, each post back is actually a form post, so instead of finding the dynamic text box, you could directly get the value via Request.Form collection. Here is the code snippet:
var list = Request.Form.AllKeys.Where(x => x.Contains("txtNameofParticipant"));
foreach (var item in list)
{
var value = Request.Form[item];
}
In this way, you could get the value and since you don't need to rely on ASP.NET engine to retrieve the value from dynamically created control, you could postpone the recreating the table in page_load event handler.
Hope it helps.

Put your btnSubmitCountParticipant_Click method data into other function with name of your choice. Call that function in method btnSubmitCountParticipant_Click and in method CreateControls(). Also cut paste the below code in btnSubmitCountParticipant_Click method
int numberofparticipants =
Convert.ToInt32(drpNoofparticipants.SelectedValue);
ViewState["numberofparticipants"] = numberofparticipants;
. This is working in my machine. Hope this helps

Yes,Dynamic controls are lost in postback,So we need save dynamic control values in Viewsate and again generate dynamic control.I added code here, this working fine
//Create Button Dynamic Control
protected void btnDyCreateControl_Click(object sender, EventArgs e)
{
try
{
int numberofparticipants = 5;
ViewState["numberofparticipants"] = numberofparticipants;
int test = (int)ViewState["numberofparticipants"];
int rowcount = 1;
int columnCount = numberofparticipants;
CreateDynamicTable(rowcount, columnCount);
}
catch (Exception ex)
{
}
}
//submit values
protected void btnSave_Click(object sender, EventArgs e)
{
try
{
List<string> listParticipantName = new List<string>();
if (ViewState["numberofparticipants"] != null)
{
int numberofparticipants = Convert.ToInt32(ViewState["numberofparticipants"]);
foreach (Control c in panelNameofParticipants.Controls)
{
if (c is Table)
{
foreach (TableRow row in c.Controls)
{
int i = 0;
foreach (TableCell cell in row.Controls)
{
if (cell.Controls[0] is TextBox)
{
string findcontrol = "txtNameofParticipant" + i;
TextBox txtParticipantName = (TextBox)cell.Controls[0].FindControl(findcontrol);
listParticipantName.Add(txtParticipantName.Text);
}
i++;
}
}
}
}
}
}
catch (Exception ex)
{
}
}
//Save ViewState
protected override object SaveViewState()
{
object[] newViewState = new object[3];
List<string> txtValues = new List<string>();
foreach (Control c in panelNameofParticipants.Controls)
{
if (c is Table)
{
foreach (TableRow row in c.Controls)
{
foreach (TableCell cell in row.Controls)
{
if (cell.Controls[0] is TextBox)
{
txtValues.Add(((TextBox)cell.Controls[0]).Text);
}
}
}
}
}
newViewState[0] = txtValues.ToArray();
newViewState[1] = base.SaveViewState();
if (ViewState["numberofparticipants"] != null)
newViewState[2] = (int)ViewState["numberofparticipants"];
else
newViewState[2] = 0;
return newViewState;
}
//Load ViewState
protected override void LoadViewState(object savedState)
{
//if we can identify the custom view state as defined in the override for SaveViewState
if (savedState is object[] && ((object[])savedState).Length == 3 && ((object[])savedState)[0] is string[])
{
object[] newViewState = (object[])savedState;
string[] txtValues = (string[])(newViewState[0]);
if (txtValues.Length > 0)
{
//re-load tables
CreateDynamicTable(1, Convert.ToInt32(newViewState[2]));
int i = 0;
foreach (Control c in panelNameofParticipants.Controls)
{
if (c is Table)
{
foreach (TableRow row in c.Controls)
{
foreach (TableCell cell in row.Controls)
{
if (cell.Controls[0] is TextBox && i < txtValues.Length)
{
((TextBox)cell.Controls[0]).Text = txtValues[i++].ToString();
}
}
}
}
}
}
//load the ViewState normally
base.LoadViewState(newViewState[1]);
}
else
{
base.LoadViewState(savedState);
}
}
//Create Dynamic Control
public void CreateDynamicTable(int rowcount, int columnCount)
{
Table tableparticipantName = new Table();
for (int i = 0; i < rowcount; i++)
{
TableRow row = new TableRow();
for (int j = 0; j < columnCount; j++)
{
TableCell cell = new TableCell();
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "txtNameofParticipant" + Convert.ToString(j);
cell.ID = "cell" + Convert.ToString(j);
cell.Controls.Add(txtNameofParticipant);
row.Cells.Add(cell);
}
tableparticipantName.Rows.Add(row);
tableparticipantName.EnableViewState = true;
ViewState["tableparticipantName"] = true;
}
panelNameofParticipants.Controls.Add(tableparticipantName);
}
Reference Link,MSDN Link, Hope it helps.

When creating your textboxes make sure you set the ClientIDMode
I recently worked on something similar. I dynamically created checkboxes in GridView rows and it worked for me.
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "txtNameofParticipant" + Convert.ToString(i);
txtNameOfParticipant.ClientIDMode = System.Web.UI.ClientIDMode.Static;

Dynamically added controls have to be created again on postback, otherwise the state of the dynamically added controls will get lost (if the controls lost how can one preserve their old state) . Now the question. When is the viewstated loaded? It is loaded in between the two events Page_Init and Load.
Following code samples are a bit modification of your code for your understanding
The aspx markup is same as yours, but with some extra controls
<form id="form1" runat="server">
<asp:DropDownList ID="drpNoofparticipants" runat="server" >
<asp:ListItem>1</asp:ListItem>
<asp:ListItem>2</asp:ListItem>
<asp:ListItem>3</asp:ListItem>
<asp:ListItem>4</asp:ListItem>
<asp:ListItem>5</asp:ListItem>
<asp:ListItem>6</asp:ListItem>
<asp:ListItem>7</asp:ListItem>
<asp:ListItem>8</asp:ListItem>
<asp:ListItem>9</asp:ListItem>
<asp:ListItem>10</asp:ListItem>
</asp:DropDownList>
<br /><asp:Button ID="btnCreateTextBoxes" runat="server" OnClick="btnSubmitCountParticipant_Click" Text="Create TextBoxes" />
<div id="divNameofParticipants" runat="server">
<asp:Panel ID="panelNameofParticipants" runat="server">
</asp:Panel>
</div>
<div>
<asp:Button ID="btnSubmitParticipants" runat="server" Text="Submit the Participants" OnClick="BtnSubmitParticipantsClicked" />
</div>
</form>
On click event of the btnCreateTextBoxes button i am creating the controls using the following code
private void CreateTheControlsAgain(int numberofparticipants)
{
try
{
ViewState["numberofparticipants"] = Convert.ToString(numberofparticipants);
Table tableparticipantName = new Table();
int rowcount = 1;
int columnCount = numberofparticipants;
for (int i = 0; i < rowcount; i++)
{
for (int j = 0; j < columnCount; j++)
{
TableRow row = new TableRow();
TableCell cell = new TableCell();
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "txtNameofParticipant" + Convert.ToString(j);
cell.ID = "cell" + Convert.ToString(j);
cell.Controls.Add(txtNameofParticipant);
row.Cells.Add(cell);
tableparticipantName.Rows.Add(row);
}
}
panelNameofParticipants.Controls.Add(tableparticipantName);
}
catch (Exception ex)
{
}
}
As mentioned above to maintain the control state, i included the re-creation of the controls in the page Load event based on the viewstate["numberofparticipants"]
protected void Page_Load(object sender, EventArgs e)
{
if (ViewState["numberofparticipants"] != null)
{
CreateTheControlsAgain(Convert.ToInt32(ViewState["numberofparticipants"]));
CreateControls();
}
}
On click event of btnSubmitParticipants button i wrote the following event and writing the participants names to the console
try
{
//String test1 = test.Value;
List<string> listParticipantName = new List<string>();
if (ViewState["numberofparticipants"] != null)
{
int numberofparticipants = Convert.ToInt32(ViewState["numberofparticipants"]);
for (int i = 0; i < numberofparticipants; i++)
{
string findcontrol = "txtNameofParticipant" + i;
var txtParticipantName = panelNameofParticipants.FindControl(string.Format("txtNameofParticipant{0}", i)) as TextBox;
listParticipantName.Add(txtParticipantName.Text);
}
}
foreach (var item in listParticipantName)
{
Response.Write(string.Format("{0}<br/>", item));
}
}
catch (Exception ex)
{
}
Hope this helps

I'm not sure if this is desired, but you're adding multiple tables to your panel, but I think you only want/need one table. So this line should be outside the outer for loop like so:
for (int i = 0; i < rowcount; i++)
{
TableRow row = new TableRow();
for (int j = 0; j < columnCount; j++)
{
TableCell cell = new TableCell();
TextBox txtNameofParticipant = new TextBox();
txtNameofParticipant.ID = "txtNameofParticipant" + Convert.ToString(i);
cell.ID = "cell" + Convert.ToString(i);
cell.Controls.Add(txtNameofParticipant);
row.Cells.Add(cell);
}
tableparticipantName.Rows.Add(row);
}
panelNameofParticipants.Controls.Add(tableparticipantName);
Additionally, FindControl will only search the direct children of the container, in this case it can only find the table, else it'll return null. so you need to search children of the panel to find the control, e.g. your table:
foreach (TableRow row in tableparticipantName.Rows)
{
TextBox txtParticipantName = (TextBox)row.FindControl(findcontrol);
listParticipantName.Add(txtParticipantName.Text);
}
If that doesn't work then doing it recursively might work better:
ASP.NET Is there a better way to find controls that are within other controls?

.Net Wizard user inputs being overwritten

I have been searching quite a bit, but unable to find something that addresses the issue I am seeing. I am sure I am missing something simple, but I have been fighting it too long, and really need to figure out what is going on. I have an existing (working) user control that I am rebuilding. It is a multi-step wizard, with each step being a type of "form" created from tables. I have successfully converted 3 of the 4 steps to divs to make them dynamic (using Bootstrap 3), but this one step, step 2, is not working like the rest. The user's input is being lost. The original code (table based) works properly. It is a simple table declared on the .ascx side:
<asp:WizardStep ID="childInformationStep" runat="server" Title="">
<%-- Some more stuff...--%>
<asp:Table cellpadding="2" class="annualSurveyTable" cellspacing="0" border="0" ID="tblChildInfo" runat="server">
</asp:Table>
<asp:WizardStep>
On the c# side, during Page_Load, a method is called to cycle through all the children of a family and dynamically build rows with pre-populated input cells for each child's First/Last Name, B-day, gender and grade. It looks like this:
private void AddChildEdit(Person child, int index)
{
TableRow row = new TableRow();
TableCell cell = new TableCell();
row.ID = "trChildFirstName_" + index;
cell.ID = "tcChildFirstName_" + index;
cell.VerticalAlign = VerticalAlign.Middle;
cell.HorizontalAlign = HorizontalAlign.Right;
cell.Wrap = false;
cell.CssClass = "registrationLabel";
cell.Text = "Child's First Name";
row.Cells.Add(cell);
cell = new TableCell();
TextBox tb = new TextBox();
tb.ID = "tbChildFirstName_" + index;
tb.Text = child.FirstName;
tb.Enabled = false;
cell.Controls.Add(tb);
row.Cells.Add(cell);
tblChildInfo.Rows.AddAt(tblChildInfo.Rows.Count, row);
// snip (more of same for last name)
row = new TableRow();
cell = new TableCell();
row.ID = "trChildBirthday_" + index;
cell.ID = "tcChildBirthday_" + index;
cell.VerticalAlign = VerticalAlign.Middle;
cell.HorizontalAlign = HorizontalAlign.Right;
cell.Wrap = false;
cell.CssClass = "registrationLabel Birthday";
cell.Text = "Child's Birth Date";
row.Cells.Add(cell);
cell = new TableCell();
DateTextBox dtb = new DateTextBox();
dtb.ID = "tbChildBirthday_" + index;
dtb.CssClass = "registrationItem Birthday";
if (child.BirthDate != DateTime.MinValue && child.BirthDate != DateTime.Parse("1/1/1900"))
dtb.Text = child.BirthDate.ToShortDateString();
cell.Controls.Add(dtb);
row.Cells.Add(cell);
tblChildInfo.Rows.AddAt(tblChildInfo.Rows.Count, row);
row = new TableRow();
cell = new TableCell();
row.ID = "trChildGender_" + index;
cell.ID = "tcChildGender_" + index;
cell.VerticalAlign = VerticalAlign.Middle;
cell.HorizontalAlign = HorizontalAlign.Right;
cell.Wrap = false;
cell.CssClass = "registrationLabel";
cell.Text = "Child's Gender";
row.Cells.Add(cell);
cell = new TableCell();
DropDownList ddlGender = new DropDownList();
ListItem l = new ListItem("", "", true);
l.Selected = true;
ddlGender.Items.Add(l);
l = new ListItem("Male", "0", true);
ddlGender.Items.Add(l);
l = new ListItem("Female", "1", true);
ddlGender.Items.Add(l);
ddlGender.ID = "ddlChildGender_" + index;
// snip (there is one more row added for grade
}
And the save method looks like it cycles through the table looking for the inputs related to the children it is looping through, and pulling in the text value, which should include any changes the user has made. It works as desired, and looks like this (BTW, I didn't write it, it looks like it could be cleaned up quite a bit :D)
private void SaveChildValues()
{
string userID = CurrentUser.Identity.Name + " - Annual Survey";
if (userID == " - Annual Survey")
userID = "Annual Survey";
int i = 0;
foreach (Person child in childrenList)
{
TableCell selectedCell = null;
foreach (TableRow row in tblChildInfo.Rows)
{
if (row.ID == "trChildBirthday_" + i)
{
foreach (TableCell cell in row.Cells)
{
if (cell.ID == "tcChildBirthday_" + i)
{
selectedCell = cell;
DateTextBox box = (DateTextBox)selectedCell.FindControl("tbChildBirthday_" + i);
if (box.Text.Trim() != string.Empty)
try { child.BirthDate = DateTime.Parse(box.Text); }
catch { }
i++;
break;
}
}
break;
}
}
}
i = 0;
foreach (Person child in childrenList)
{
TableCell selectedCell = null;
foreach (TableRow row in tblChildInfo.Rows)
{
if (row.ID == "trChildGender_" + i)
{
foreach (TableCell cell in row.Cells)
{
if (cell.ID == "tcChildGender_" + i)
{
selectedCell = cell;
DropDownList ddl = (DropDownList)selectedCell.FindControl("ddlChildGender_" + i);
if (ddl.SelectedValue != string.Empty)
try { child.Gender = (Gender)Enum.Parse(typeof(Gender), ddl.SelectedValue); }
catch { }
i++;
break;
}
}
break;
}
}
}
i = 0;
foreach (Person child in childrenList)
{
TableCell selectedCell = null;
foreach (TableRow row in tblChildInfo.Rows)
{
if (row.ID == "trChildGrade_" + i)
{
foreach (TableCell cell in row.Cells)
{
if (cell.ID == "tcChildGrade_" + i)
{
selectedCell = cell;
DropDownList ddl = (DropDownList)selectedCell.FindControl("ddlChildGrade_" + i);
if (ddl.SelectedValue != string.Empty)
try { child.GraduationDate = Person.CalculateGraduationYear(Int32.Parse(ddl.SelectedValue), CurrentOrganization.GradePromotionDate); }
catch { }
i++;
break;
}
}
break;
}
}
}
}
Now, here are the changes that I have made to that section. The page loads, and runs through all the motions, yet when the save happens, it is pulling in the original DB value from the child record again instead of the user's input. I simply changed the table to an ASP Panel in the .ascx file:
<asp:WizardStep ID="childInformationStep" runat="server" Title="">
<%-- Some more stuff...--%>
<asp:Panel ID="tblChildInfo" runat="server" ClientIDMode="Static">
</asp:Panel>
<asp:WizardStep>
I have changed the dynamic row creation to dynamic divs, laid out for bootstrap 3:
private void AddChildEdit(Person child, int index)
{
Panel childRow = new Panel();
childRow.ID = "ChildRow_" + index;
childRow.CssClass = "form-horizontal";
LiteralControl childTitle = new LiteralControl();
childTitle.Text = string.Format("<h4>Child {0}:</h4>", (index + 1).ToString());
childRow.Controls.Add(childTitle);
Panel formGroup = new Panel();
formGroup.ID = "trChildFirstName_" + index;
formGroup.CssClass = "form-group";
childRow.Controls.Add(formGroup);
Panel inputContainer = new Panel();
inputContainer.CssClass = "col-sm-8";
formGroup.Controls.Add(inputContainer);
TextBox tb = new TextBox();
tb.ID = "tbChildFirstName_" + index;
tb.Text = child.FirstName;
tb.Enabled = false;
inputContainer.Controls.Add(tb);
Label inputLabel = new Label();
inputLabel.ID = "tcChildFirstName_" + index;
inputLabel.CssClass = "col-sm-3 control-label registrationLabel";
inputLabel.Text = "First Name";
inputLabel.AssociatedControlID = tb.ID;
formGroup.Controls.AddAt(0, inputLabel);
tblChildInfo.Controls.Add(childRow);
// snip (more code for adding Last Name row
formGroup = new Panel();
formGroup.ID = "trChildBirthday_" + index;
formGroup.CssClass = "form-group";
inputContainer = new Panel();
inputContainer.ID = "tcChildBirthday_" + index;
inputContainer.CssClass = "col-sm-8";
formGroup.Controls.Add(inputContainer);
TextBox dtb = new TextBox();
dtb.ID = "tbChildBirthday_" + index;
dtb.CssClass = "form-control survey-control date-mask registrationItem";
dtb.Attributes.Add("placeholder", "MM/DD/YYYY");
if (child.BirthDate != DateTime.MinValue && child.BirthDate != DateTime.Parse("1/1/1900"))
dtb.Text = child.BirthDate.ToString("MM/dd/yyyy");
inputContainer.Controls.Add(dtb);
inputLabel = new Label();
inputLabel.CssClass = "col-sm-3 control-label";
inputLabel.Text = "BirthDate";
inputLabel.AssociatedControlID = dtb.ID;
formGroup.Controls.AddAt(0, inputLabel);
childRow.Controls.Add(formGroup);
// snip (more of the same, adding two more rows for gender and grade)
}
And I simplified the save method to:
private void SaveChildValues()
{
string userID = CurrentUser.Identity.Name + " - Annual Survey";
if (userID == " - Annual Survey")
userID = "Annual Survey";
int i = 0;
foreach (Person child in childrenList)
{
try
{
TextBox box = (TextBox)tblChildInfo.FindControl("tbChildBirthday_" + i);
if (box.Text.Trim() != string.Empty)
child.BirthDate = DateTime.Parse(box.Text);
}
catch { }
try
{
DropDownList ddl = (DropDownList)tblChildInfo.FindControl("ddlChildGender_" + i);
if (ddl.SelectedValue != string.Empty)
child.Gender = (Gender)Enum.Parse(typeof(Gender), ddl.SelectedValue);
}
catch {}
try
{
DropDownList ddl = (DropDownList)tblChildInfo.FindControl("ddlChildGrade_" + i);
if (ddl.SelectedValue != string.Empty)
child.GraduationDate = Person.CalculateGraduationYear(Int32.Parse(ddl.SelectedValue), CurrentOrganization.GradePromotionDate);
}
catch { }
i++;
}
As far as I understand it, my code does not change any fundamental behavior, other than it is using div elements to build out the dynamic content rather then adding rows to a table. What am I missing that is causing my updated code to lose the users' input?
NOTE: this is step two, where the information is rendered, captured for the child info. The save method is not executed until step 4, so the input data should be persisting through two more steps, and remain in tact. I have tried using debugger, but can never see the users input. I don't know if I am looking for it at the wrong breakpoints, but I can't seem to find where the user input is coming back with the post, and when it SHOULD be getting written to the inputs. Any help would be greatly appreciated.

You could try moving the dynamic creation of the fields into the Page_Init section rather than the Page_Load.