I'm reading a list of id numbers from a database table into a placeholder textbox but however; if I do a button click the data is removed.
protected void btnSearch_Click(object sender, EventArgs e)
{
while (myReader.Read())
{
TextBox txt = new TextBox();
txt.Text = (string)myReader["idNumber"];
txt.ID = "txt" + i;
txt.ReadOnly = true;
ContentPlaceHolder1.Controls.Add(txt);
ContentPlaceHolder1.Controls.Add(new LiteralControl(" "));
i++;
}
}
This is a common problem when working with dynamically added controls in web forms (especially if you're coming from a winforms background). Pages in ASP.NET Web Forms are stateless, and reconstructed on each postback. Therefore, if you add a control to a page during a server event, you'll also have to add it to the page on subsequent Page loads if you want it to appear. You can accomplish this with something similar to the following:
protected List<Control> ControlCache
{
get => (List<Control>)(Session["cachedControlsForPageX"] = (Session["cachedControlsForPageX"] as List<Control>) ?? new List<Control>());
set => Session["cachedControlsForPageX"] = value;
}
/* If you can't use C# 7's expression bodied property accessors, here's the equivalent in blocks:
protected List<Control> ControlCache
{
get { return (List<Control>)(Session["cachedControlsForPageX"] = (Session["cachedControlsForPageX"] as List<Control>) ?? new List<Control>()); }
set { Session["cachedControlsForPageX"] = value; }
}
*/
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
foreach (var control in ControlCache)
{
ContentPlaceHolder1.Controls.Add(control);
ContentPlaceHolder1.Controls.Add(new LiteralControl(" "));
}
}
else
ControlCache = null;
}
protected void btnSearch_Click(object sender, EventArgs e)
{
while (myReader.Read())
{
TextBox txt = new TextBox();
txt.Text = (string)myReader["idNumber"];
txt.ID = "txt" + i;
txt.ReadOnly = true;
ContentPlaceHolder1.Controls.Add(txt);
ContentPlaceHolder1.Controls.Add(new LiteralControl(" "));
ControlCache.Add(txt);
i++;
}
}
Related
Hi i am creating dropdownlist dynamically but on post back it is loosing the value and i am unable to get values on button click event.
private void CreateDropdownListEmployee(string id,Panel pnl, DataTable dt)
{
DropDownList drp = new DropDownList();
drp.ID = id;
drp.CssClass = "activeuserTxt";
drp.ClientIDMode = ClientIDMode.Static;
drp.DataSource = dt;
drp.DataTextField = "name";
drp.DataValueField = "id";
drp.DataBind();
pnl.Controls.Add(drp);
}
For the dynamic texbox i am using the below code on PAge_Init
protected void Page_Init(object sender, EventArgs e)
{
try
{
int SNID = 0;
List<string> keysNetmr = Request.Form.AllKeys.Where(key => key.Contains("txt")).ToList();
foreach (string key in keysNetmr)
{
this.CreateTextBox("txtNermr" + SNID, 100, pnlSN);
SNID++;
}
}
catch (Exception ex) { }
}
private void CreateTextBox(string id, int width, Panel pnl)
{
TextBox txt = new TextBox();
txt.ID = id;
txt.Width = width;
txt.Attributes.Add("autocomplete", "off");
txt.CssClass = "activeuserTxt";
pnl.Controls.Add(txt);
}
Can anyone help me on this.
I'm creating dynamically controls, assigning it at the same dynamically names and ID's but when I click over a button "A" and then over the button "B" and then again to the button "A" this throw me an error
Multiple controls with the same ID were found. FindControl requires that controls have unique IDs.
this is my code and how I try to avoid the repeating I
protected void DynamicButton()
{
//BAD TOOLS INTO THE LIST AND SHOW
List.ListUsers listsArea = new List.ListUsers();
List<Data.Area> Area = listsArea.AreaList();
List<Data.Area> ListOfEquiposNoOk = Area.Where(x => x.AREA == "ENG" && x.STANDBY == 1).ToList();
List<Button> BotonesBad = new List<Button>();
var TeamBad = ListOfEquiposNoOk.Select(x => x.TEAM).Distinct().ToList();
foreach (var team in TeamBad)
{
Button newButtonBad = new Button();
if (newButtonBad.ID != newButtonBad.ID)
{
BotonesBad = Bad.Controls.OfType<Button>().ToList();
BotonesBad.Add(newButtonBad);
}
else
{
newButtonBad.CommandName = "Btn" + Convert.ToString(team);
newButtonBad.ID = "BtnB_" + Convert.ToString(team);
newButtonBad.Text = team;
newButtonBad.CommandArgument = "ENG";
newButtonBad.Click += new EventHandler(newButton_Click);
Bad.Controls.Add(newButtonBad);
newButtonBad.Click += new EventHandler(newButton_Click);
newButtonBad.CssClass = "btn-primary outline separate";
}
}
I need the ID's to fire an UpdatePanel
ADDED
public partial class Dashboard : System.Web.UI.Page
{
static bool enableGood = false;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DynamicButton();
}
else if(enableGood)
{
DynamicButton();
}
}
protected void DButton(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this, this.GetType(), "Pop", "showAndHide();", true);
enableGood = true;
DynamicButton();
}
Assuming "team" is an object in this line:
newButtonBad.ID = "BtnB_" + Convert.ToString(team);
There could be your problem. ".ToString()" usually returns the type as string. So every button will get the same name (since they are all of type "team").
You could override ToString() in your team object, or use a specific team property (e.g team.ID). You could use the property like this:
newButtonBad.ID = "BtnB_" + team.ID.ToString();
Also as already pointed out in the comments, change your evaluation from
if (newButtonBad.ID != newButtonBad.ID)
to
if (team.ID != newButtonBad.ID)
That should do the trick.
First time poster, long time lurker. I am having some trouble with my ASP.NET page, and I hope someone can help me resolve my issue.
Basically, I have a bunch of checkboxes in a gridview, and two buttons: a 'find' button, and a 'save' button. The 'find' can set the value of the checkbox, but if a user unchecks it, I want to capture that change when the user hits 'save'. Currently, it does not work.
Relevant ASPX:
<%# Page Language="C#" AutoEventWireup="true" EnableViewState="true" CodeBehind="FindTransactions.aspx.cs" Inherits="Basic.FindTransactions" MasterPageFile="~/Trans.Master" %>
Relevant Code Behind here:
Page:
public partial class FindTransactions : System.Web.UI.Page
{
GridView _gridview = new GridView() { ID = "_gridView" };
DataTable _datatable = new DataTable();
Int32 _buyerID = new Int32();
protected void Page_Load(object sender, EventArgs e)
{
}
"Find" button:
protected void Find_Click(object sender, EventArgs e)
{
//truncated
_datatable.Rows.Add(
//filled with other data from a custom object.
);
ViewState["_datatable"] = _datatable;
ViewState["_buyerID"] = _buyerID;
BuildGridView((DataTable)ViewState["_datatable"],(Int32)ViewState["buyerID"]);
}
BuildGridView function:
protected void BuildGridView(DataTable d, Int32 b)
{
_gridview.DataKeyNames = new String[] {"Transaction ID"};
_gridview.AutoGenerateColumns = false;
_gridview.RowDataBound += new GridViewRowEventHandler(OnRowDataBound);
for(Int32 i = 0; i < d.Columns.Count; i++)
{
Boundfield boundfield = new BoundField();
boundfield.DataField = d.Columns[i].ColumnName.ToString();
boundfield.HeaderText = d.Columns[i].ColumnName.ToString();
_gridview.Columns.Add(boundfield);
}
_gridview.DataSource = d;
_gridview.DataBind();
//truncated
Panel1.Controls.Add(_gridview);
}
Row Bound Event handler:
protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
String controlID = "checkBox";
CheckBox c = new CheckBox() { ID = controlID};
c.Enabled = true;
Boolean success;
Boolean v;
success = Boolean.TryParse(e.Row.Cells[8].Text, out v);
e.Row.Cells[8].Controls.Add(c);
if (success)
{
c.Checked = v;
if (c.Checked)
{
//Will uncomment once other things work
//e.Row.Visible = false;
}
}
else
{
c.Checked = false;
}
}
}
All of that works. Here is where it starts to break down:
"Save" button:
protected void Save_Click(object sender, EventArgs e)
{
//Both for troubleshooting and both return 0. (Expected for datatable)
Label1.Text = _gridview.Rows.Count.ToString();
Label2.Text = _datatable.Rows.Count.ToString();
/*truncated
*/
if (grid.Rows.Count == 0)
{
BuildGridView((DataTable)ViewState["infoTable"], (Int32)ViewState["guestID"]);
}
foreach (GridViewRow r in grid.Rows)
{
if (r.RowType == DataControlRowType.DataRow)
{
CheckBox cb = (CheckBox)r.FindControl("checkBox");
if (cb != null && cb.Checked)
{
//This never seems to modify the label.
//Will put code to modify database here.
Label2.Text += "Hi " + r.RowIndex.ToString();
}
}
}
}
After I hit the save button, PostBack occurs and GridView is empty (Rows.Count is 0). ViewState appears to be lost before I get a chance to loop through the GridView rows to determine the checkbox values.
At the end of it all, I just want to capture the status of those checkboxes, changed by user interaction or not, by hitting the 'Save' button.
I found some other articles, but a lot of them haven't worked when I tried implementing the various fixes.
This one seems to be the closest that describes my issue, and the code is structured similarly, but I don't quite understand how to implement the fix: GridView doesn't remember state between postbacks
[New simplified code to illustrate problem:]
namespace GridViewIssue
{
public partial class GridViewNoMaster : System.Web.UI.Page
{
GridView _gridView = new GridView() { ID = "_gridView" };
DataTable _dataTable = new DataTable();
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Find_Click(object sender, EventArgs e)
{
BuildDataTable();
List<String> list = new List<String>();
list.Add("1");
list.Add("User");
list.Add("10/12/2014");
foreach (String s in list)
{
_dataTable.Rows.Add(
list[0],
list[1],
list[2]
);
}
BuildGridView();
//Feedback.Text = _gridView.Rows.Count.ToString();
}
protected void Save_Click(object sender, EventArgs e)
{
Feedback.Text = "Save Clicked, PostBack: " + IsPostBack + ", GridView Row Count: " + _gridView.Rows.Count + ", GridView ViewState: " + _gridView.EnableViewState;
foreach (GridViewRow r in _gridView.Rows)
{
if(r.RowType == DataControlRowType.DataRow)
{
Feedback.Text = "In DataRow type" + _gridView.Rows.Count;
}
}
}
protected void BuildDataTable()
{
_dataTable.Columns.Add("Transaction ID", typeof(String));
_dataTable.Columns.Add("Name", typeof(String));
_dataTable.Columns.Add("Date", typeof(String));
}
protected void BuildGridView()
{
for (Int32 i = 0; i < _dataTable.Columns.Count; i++)
{
BoundField b = new BoundField();
b.DataField = _dataTable.Columns[i].ColumnName.ToString();
b.HeaderText = _dataTable.Columns[i].ColumnName.ToString();
_gridView.Columns.Add(b);
}
_gridView.DataKeyNames = new String[] { "Transaction ID" };
_gridView.AutoGenerateColumns = false;
_gridView.DataSource = _dataTable;
_gridView.DataBind();
Panel1.Controls.Add(_gridView);
}
}
}
Here i am updating the gridview value but the value is not updating..TextBox txtID,TextBox txtName,TextBox txtAge retains the older value only and the value is not getting updated..Can anyone tel me like what am i doing wrong here
Here is my code
protected void gvTemp_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
CreateDataSkeletton(Convert.ToInt16(Session["intTabIndex"]));
GridViewRow row = (GridViewRow)gvTemp.Rows[e.RowIndex];
int autoid = Int32.Parse(gvTemp.DataKeys[e.RowIndex].Value.ToString());
int id = Convert.ToInt32(gvTemp.DataKeys[e.RowIndex].Values[0].ToString());
activeTabIndex = Convert.ToInt16(Session["activeTabIndex"]);
TextBox txtID = ((TextBox)gvTemp.Rows[e.RowIndex].FindControl("txtId"));
TextBox txtName = (TextBox)gvTemp.Rows[e.RowIndex].FindControl("txtName");
TextBox txtAge = (TextBox)gvTemp.Rows[e.RowIndex].FindControl("txtAge");
dataSetInSession.Tables["Days" + activeTabIndex.ToString()].Rows[e.RowIndex]["ID"] = txtID.Text;
dataSetInSession.Tables["Days" + activeTabIndex.ToString()].Rows[e.RowIndex]["Name"] = txtName.Text;
dataSetInSession.Tables["Days" + activeTabIndex.ToString()].Rows[e.RowIndex]["Age"] = txtAge.Text;
gvTemp.DataSource = dataSetInSession.Tables["Days" + activeTabIndex.ToString()];
gvTemp.DataBind();
gvTemp.EditIndex = -1;
}
and
private void CreateDataSkeletton(int intTabIndex)
{
dataSetInSession = new DataSet();
Session["intTabIndex"] = intTabIndex;
if (Session["dataSetInSession"] != null)
{
dataSetInSession = (DataSet)Session["dataSetInSession"];
}
if (dataSetInSession.Tables["Days" + intTabIndex].Rows.Count > 0)
{
gvTemp.DataSource = dataSetInSession.Tables["Days" + intTabIndex];
gvTemp.DataBind();
}
else
{
gvTemp.DataSource = dataSetInSession.Tables["Days"];
gvTemp.DataBind();
}
temp.Controls.Add(gvTemp);
}
Any suggestion??
EDIT(1):
protected void Page_Init(object sender, EventArgs e)
{
if (!IsPostBack)
{
AddDataTable();
}
dataSetInSession = new DataSet();
if (Session["dataSetInSession"] != null)
{
dataSetInSession = (DataSet)Session["dataSetInSession"];
}
if (Session["dynamicTabIDs"] != null)
{
//if dynamicTabIDs are in session, recreating the Tabs
//that are associated with the Tab IDs
//and adding them to the TabContainer that will contain
//all of the dynamic tabs.
//retrieving the tab IDs from session:
dynamicTabIDs = (List<string>)Session["dynamicTabIDs"];
if (TabContainerContent.ActiveTabIndex == -1)
{
TabContainerContent.ActiveTabIndex = Convert.ToInt16(Session["intTabIndex"]);
}
CreateDataSkeletton(Convert.ToInt16(Session["intTabIndex"]));
//looping through each TabID in session
//and recreating the TabPanel that is associated with that tabID
foreach (string tabID in dynamicTabIDs)
{
//creating a new TabPanel that is associated with the TabID
AjaxControlToolkit.TabPanel tab = new AjaxControlToolkit.TabPanel();
//TabContainerContent.ActiveTabIndex = tab;
//Setting the ID property of the TabPanel
tab.ID = tabID;
//setting the TabPanel's HeaderText
tab.HeaderText = "Days " + (TabContainerContent.Tabs.Count + 1).ToString();
//creating a Label to add to the TabPanel...at this point you'll have to
//create whatever controls are required for the tab...
Label tabContent = new Label();
//Giving the Label an ID
tabContent.ID = "lbl_tab_" + TabContainerContent.Tabs.Count.ToString();
//Setting the Label's text
tabContent.Text = "Tab " + (TabContainerContent.Tabs.Count + 1).ToString();
//Adding the Label to the TabPanel
tab.Controls.Add(tabContent);
//Adding the TabPanel to the TabContainer that contains the dynamic tabs
TabContainerContent.Tabs.Add(tab);
}
}
else
{ //Creating a new list of dynamicTabIDs because one doesn't exist yet in session.
dynamicTabIDs = new List<string>();
}
}
protected void Page_Load(object sender, EventArgs e)
{
}
Read Page Life Cycle
And you will get, that if you want to bind in code-behind, you should do it in Init Event, other wise there are no events will fire.
It seems to be Page.IsPostback problem.Need to add Page.IsPostback property in your page_load like
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
// Put your code inside that.
}
}
Actually your control is getting new value but when you click for updation then it calls old value from page_load.So try to put Page.IsPostback into your page_load event,Just like i mentioned.
I hope it helps.
I am dynamically creating buttons which each selection of a dropdownlist.
With the following code I am adding an event handler to each button.
button.Click += new System.EventHandler(button_Click);
PlaceHolder1.Controls.Add(button);
private void button_Click(object sender, EventArgs e)
{
//Do something...
Response.Write("hello");
}
But unfortunately it does not fire that event and gives me an error as following
button_Click 'Index.button_Click(object, System.EventArgs)' is a 'method', which is not valid in the given context
How do I handle this?
protected void DropDownList1_SelectedIndexChanged1(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this, typeof(Page), "Close", "javascript:OpenPopUp1();", true);
if (Session["filter"] == DropDownList1.SelectedValue)
{
}
else
{
if (Session["filter"] == "")
{
Session["filter"] = DropDownList1.SelectedValue + ":";
}
else
{
Session["filter"] = DropDownList1.SelectedValue + ":" + Session["filter"];
}
}
string asd = Session["filter"].ToString();
string[] split = asd.Split(':');
DropDownList1.Items.RemoveAt(DropDownList1.SelectedIndex);
for (int i = 0; i < split.Count(); i++)
{
string filter = split[i].ToString();
Button button = new Button();
button.Text = split[i].ToString();
button.ID = split[i].ToString();
button.Attributes.Add("onclick", "remove(" + split[i].ToString() + ")");
button.Click += new System.EventHandler(button_Click);
PlaceHolder1.Controls.Add(button);
}
}
The above shows the whole code of dropdownselected index.
button.Click += new System.EventHandler(button_Click);
PlaceHolder1.Controls.Add(button);
} // <-- end your current method with a curly brace
// Now start a new method
private void button_Click(object sender, EventArgs e)
{
//do something...
Response.Write("hello");
}
It's hard to say what you're going after, as there are a number of issues going on here. Since your dynamically generated buttons are being created in the SelectedIndexChanged event handler of your dropdown, they are not going to exist, nor are their event bindings, on the next postback. This means they can show up on the page, but clicking them won't do anything.
Secondly, since you are storing the SelectedValue to Session, and then using that value to set the Button IDs, you are going to be creating buttons with duplicate IDs if the user ever comes back to the page. (I noticed you are removing the list item once selected, but it would come back if the user refreshed the page, while the session object would remain populated.)
Last oddity, I wasn't able to find where your particular exception is handling, nor able to reproduce it. Which version of .NET are you programming against? Are you invoking the button click event anywhere from code-behind?
Now, that all said, I'm providing the following fix (or at least improvement):
protected void Page_Init(object sender, EventArgs e)
{
CreateButtons();
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this, typeof(Page), "Close", "javascript:OpenPopUp1();", true);
if (Session["filter"] == DropDownList1.SelectedValue)
{
}
else
{
if (Session["filter"] == "")
{
Session["filter"] = DropDownList1.SelectedValue + ":";
}
else
{
Session["filter"] = DropDownList1.SelectedValue + ":" + Session["filter"];
}
}
DropDownList1.Items.RemoveAt(DropDownList1.SelectedIndex);
CreateButtons();
}
private void CreateButtons()
{
PlaceHolder1.Controls.Clear();
if (Session["filter"] != null)
{
string asd = Session["filter"].ToString();
string[] split = asd.Split(':');
for (int i = 0; i < split.Count(); i++)
{
string filter = split[i].ToString();
Button button = new Button();
button.Text = split[i].ToString();
button.ID = split[i].ToString();
button.Attributes.Add("onclick", "remove(" + split[i].ToString() + ")");
button.Click += new System.EventHandler(button_Click);
PlaceHolder1.Controls.Add(button);
}
}
}
private void button_Click(object sender, EventArgs e)
{
//do something...
Response.Write("hello");
}