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Generate textbox in gridview on button click? ASP.NET C#

I have a gridview in which textbox is generated dynamically on RowDataBound event.I want to generate 3 more textbox below gridview on button click.
Here is my gridview
Here is my code behind:
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
string s = Session["num"].ToString();
int num = Int32.Parse(s);
if (e.Row.RowType == DataControlRowType.DataRow)
{
for (int i = 0; i <num; i++)
{
TextBox txt = new TextBox();
txt.Height = 25;
txt.Width = 150;
txt.Font.Size = 10;
txt.ID = "txt" + i;
txt.Text = e.Row.Cells[i].Text.Replace(" ", "");
e.Row.Cells[i].Controls.Add(txt);
}
}
}

Not sure what your exact problem is, but this Link might help you. Anyway, you can simply generate TextBox dynamically using Button Click Event.
The example shown below generates three TextBox Control on a Click Event:
TextBox txt;
static int i = 0;
protected void Button1_Click(object sender, EventArgs e)
{
if(i%2==0)
{
for (int j = 0; j < 3; j++)
{
txt= new TextBox();
txt.Height = 25;
txt.Width = 150;
txt.Font.Size = 10;
txt.ID = j.ToString();
PlaceHolder1.Controls.Add(txt);
}
}
i++;
}
Note: When you dynamically add controls to an ASP.NET page at runtime the object references are lost at postback because they have no object reference variable in the codebehind.

Placeholder controls count always return 0 in button click

I created some TextBox dynamically using the code below and I entered some text in this TextBox. Now I want to read this control's ID while adding the text into a database. How can I get the ID of this TextBox on the click of a Button.
for (int i = 0; i < dv_count; i++)
{
TextBox txt_box = new TextBox();
txt_box.Text = "";
txt_box.ID = "s" + i;
placeholder1.Controls.Add(txt_box);
}
protected void btn_act_proceed_Click(object sender, EventArgs e)
{
int count = placeholder1.Controls.Count; //always return 0
if (count > 0)
{
int dv_count = count / 2;
for (int i = 0; i < dv_count; i++)
{
TextBox lbl_type = (TextBox )placeholder1.FindControl("s" + i);
}
}
}

Try this
In your Aspx Page
<div runat="server" id="plcholder">
</div>
<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />
now in code behind
protected void Page_Load(object sender, EventArgs e)
{
populate();
}
public void populate()
{
for (int i = 0; i < 3; i++)
{
TextBox tb = new TextBox();
tb.ID = "s" + i;
tb.Text = "Hello" + i;
plcholder.Controls.Add(tb);
}
}
protected void Button1_Click(object sender, EventArgs e)
{
int cont = plcholder.Controls.Count;
for (int i = 0; i < cont-1; i++)
{
TextBox tx = (TextBox)plcholder.FindControl("s" + i);
Response.Write(tx.Text);
}
}

Control will be lost during postback. So on preinit you need to create the controls again.
Or you can keep your controls in session and get it back from postback.
A good link http://www.codeproject.com/Articles/3684/Retaining-State-for-Dynamically-Created-Controls-i
http://www.codeproject.com/Articles/502251/How-to-create-controls-dynamically-in-ASP-NET-and

I don't see you adding controls to the placeholder in first place. try this
for (int i = 0; i < dv_count; i++)
{
TextBox txt_box = new TextBox();
txt_box.Text = "";
txt_box.ID = "s" + i;
placeholder1.Controls.Add(txt_box);
}
TextBox lbl_type = (TextBox)placeholder1.FindControl("s" + i);

Button Click Frequency Array

I need to make a ListBox that displays how often a Button is clicked.
The user chooses how many buttons are available to click. Here is what I've tried:
int clicked;
clicked = int.Parse(((Button)(sender)).Text);
freq_array[clicked]++;
for (int i = 0; i < freq_array[clicked]; i++)
lstFrequencies.Items[clicked] = clicked + "\t\t" + freq_array[clicked];
freq_array uses the 'clicked' variable to add to the frequency that button has been clicked. Or, it's supposed to.
When I debug it, 'clicked' always comes out to 0. I want 'clicked' to equal the text value of the button that's clicked. When I try to run the program, I get an error saying "Input string was not in correct format."
Edit:
I was able to fix my program with help from you guys. I realized I didn't show enough of my code to be clear enough, and I apologize for that. I had to add some things and move things around and got it soon enough. Thank you all.
Here is the code just for those who may need help in the future:
public partial class Form1 : Form
{
int[] freq_array = new int[11];
int[] numList = new int[11];
int oBase = 0;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
invisiblity();
}
private void invisiblity()
{
foreach (Control ctrl in this.Controls)
{
if (ctrl is Button)
if (Char.IsDigit(ctrl.Text[0]))
ctrl.Visible = false;
}
}
private void btnSetBase_Click(object sender, EventArgs e)
{
Form2 frmDialog = new Form2();
frmDialog.ShowDialog(this);
if (frmDialog.DialogResult == DialogResult.OK)
{
oBase = frmDialog.Base;
//lblOutDigits.Text = oBase.ToString();
for (int i = 0; i < oBase; i++)
{
numList[i] = i;
}
}
ShowBaseButtons(oBase);
}
private void ShowBaseButtons(int last_digit)
{
invisiblity();
foreach (Control ctrl in this.Controls)
{
if (ctrl is Button)
if (Char.IsDigit(ctrl.Text[0]))
if (int.Parse(ctrl.Text) <= last_digit - 1)
ctrl.Visible = true;
}
}
private void btnN_Click(object sender, EventArgs e)
{
lblOutDigits.Text += ((Button)(sender)).Text;
int clicked = int.Parse(((Button)(sender)).Text);
freq_array[clicked]++;
}
private void btnShowFreq_Click(object sender, EventArgs e)
{
lstFrequencies.Items.Clear();
for (int i = 0; i < oBase; i++)
lstFrequencies.Items.Add(numList[i] + " \t\t\t" + freq_array[i]);
}

Your code should work as long as your Button Text is actually just a number. Since what you are trying to do is create an index, what I usually do is use the Tag Property of the control, set it to the Index I want in the designer and then cast that to an Int.
i.e.
if (int.TryParse(((Button)sender).Tag.ToString(), out clicked))
freq_array[clicked]++;
I believe what is happening is that you are not initializing your ListBox, This example Code does work using your initial method. Just create a new Form and paste it in and test.
public partial class Form1 : Form
{
ListBox lstFrequencies = new ListBox();
int[] freq_array = new int[10];
public Form1()
{
InitializeComponent();
Size = new Size(400, 400);
lstFrequencies.Location = new Point(150, 0);
lstFrequencies.Size = new Size(150, 200);
Controls.Add(lstFrequencies);
int top = 0;
for (int i = 0; i < 10; i++)
{
Button btn = new Button();
btn.Size = new Size(70, 30);
btn.Location = new Point(5, top);
Controls.Add(btn);
top += 35;
btn.Tag = i;
btn.Text = i.ToString();
btn.Click += new EventHandler(btn_Click);
lstFrequencies.Items.Add(i.ToString());
}
}
void btn_Click(object sender, EventArgs e)
{
int clicked;
clicked = int.Parse(((Button)(sender)).Text);
freq_array[clicked]++;
lstFrequencies.Items[clicked] = clicked + "\t\t" + freq_array[clicked]; //Cleaned up you do not need to iterate your list
// Using my example code
//if (int.TryParse(((Button)sender).Tag.ToString(), out clicked))
//{
// freq_array[clicked]++;
// lstFrequencies.Items[clicked] = clicked + "\t\t" + freq_array[clicked];
//}
}
}

Your code always comes out to 0 because you never assign last clicked value to button text. Try this code:
int clicked = 0;
private void button1_Click(object sender, EventArgs e)
{
clicked = Convert.ToInt32(((Button)sender).Text);
lstFrequencies.Items.Add(((Button)sender).Name + " " + ++clicked);
button1.Text = clicked.ToString(); // you lose this line
}
EDIT: Counter from variable member
int clicked = 0;
private void button1_Click(object sender, EventArgs e)
{
// if you want to display button name, change .Text to .Name
lstFrequencies.Items.Add(((Button)sender).Text + " " + ++clicked);
}

Click events on Array of buttons

How can I get the name of the object last clicked on a panel? The trick is there is a big array of buttons on the panel (btn[1] ... btn [200]). How can I check if I clicked on button b[180], or b[11] or even outside the panel (no button)? Also the buttons are generated at page load via coding.
Thank you. Anna
EDIT:
Thank you! Another issue that arose (this generated a NULL object reference):
I have a method on the same level as buttonHandler(), it is named HowManyClicked() and it's called from within buttonHandler(). Inside HowManyClicked() I want to identify Button btn1 = Panel2.FindControl(x) as Button; where x is, for example, buttonArray[2,3]. But I always get NULL. Is the button array buttonArray not identifiable by name once out of the method that generated it??
public void buttonHandler(object sender, EventArgs e)
{
Button btn = sender as Button;
//string tt = btn.ToolTip.ToString();
btn.BackColor = Color.Red;
statusL.Text = HowManyClicked().ToString();
}
public int HowManyClicked()
{
int sum=0;
for (int a = 0; a < 10; a++)
for (int b = 0; b < 14; b++)
{
string x = "buttonArray[" + a + ", " + b + "]";
statusL.Text = x;
Button btn1 = Panel2.FindControl(x) as Button;
if (btn1.BackColor == Color.Red) sum += 1;
}
return sum;
}

As #AVD commented you can get the button originating the postback casting the sender object, you can also use the CommandName and CommandArgument properties from the button object (they are usually used when the button is inside a Grid, DataList etc but you can use them in this context if you need):
protected void Page_Init(object sender, EventArgs e)
{
var s = Enumerable.Range(1, 10);
foreach (var item in s)
{
var b = new Button();
b.Text = "My Button " + item.ToString();
b.CommandName = "custom command";
b.CommandArgument = item.ToString();
b.Click += new EventHandler(b_Click);
this.myPanel.Controls.Add(b);
}
}
void b_Click(object sender, EventArgs e)
{
var current = sender as Button;
this.lblMessage2.Text = "Clicked from array buttons: <br/>Command Name: " + current.CommandName + "<br/>Args: " + current.CommandArgument + "<br/>Button Unique ID: " + current.UniqueID + "<br/>Client ID: " + current.ClientID;
}
Page:
<asp:Panel runat="server" ID="myPanel">
</asp:Panel>
<asp:Label ID="lblMessage2" runat="server" />
This code generates something like:
As an additional note, Microsoft recommends to create dynamic controls in the PreInit event or in case you are using a master page, in the Init event
source
Edited
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
this.ViewState["count"] = 0;
}
}
protected void Page_Init(object sender, EventArgs e)
{
var s = Enumerable.Range(1, 10);
foreach (var item in s)
{
var b = new Button();
b.Text = "My Button " + item.ToString();
b.Click += new EventHandler(buttonHandler);
this.myPanel.Controls.Add(b);
}
}
void buttonHandler(object sender, EventArgs e)
{
// update here your control
var b = sender as Button;
b.BackColor = Color.Red;
HowManyClicked();
}
private void HowManyClicked()
{
var c = (int)this.ViewState["count"];
c++;
this.ViewState["count"] = c;
this.lblMessage2.Text = "Clicked controls: " + this.ViewState["count"].ToString();
}
This produced:

How can I get the name of the object last clicked on a panel?
The first parameter of click handler returns the reference of control/object has raised the event.
public void buttonHandler(object sender, EventArgs e)
{
Button btn=sender as Button;
....
}

I just figured out another fix by just redefining HowManyClicked() so I am adding it here below. Not sure still why the first method (the one in my question) didn't work also. Here goes:
public int HowManyClicked()
{
int sum=0;
foreach (Control cnt in this.Panel2.Controls)
if (cnt is Button)
{
Button btn = (Button)cnt;
if (btn.BackColor == Color.Red)
sum += 1;
}
return sum;
}
}
Thanks everyone!

ASP.NET dynamic controls count (creating controls as you go)

I'm trying to create a composite ASP.NET control that let's you build an editable control collection.
My problem is that when I press the add or postback button (which does nothing other than to postback the form) any values entered in the text boxes are lost.
I can't get it to work when the number of controls change between postbacks. I need to basically be able to recreate the control tree at two different times in the control life-cycle depending on the view state property ControlCount.
This test can be used to reproduce the issue:
public class AddManyControl : CompositeControl
{
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
EnsureChildControls();
}
protected override void CreateChildControls()
{
var count = ViewState["ControlCount"] as int? ?? 0;
for (int i = 0; i < count; i++)
{
var div = new HtmlGenericControl("div");
var textBox = new TextBox();
textBox.ID = "tb" + i;
div.Controls.Add(textBox);
Controls.Add(div);
}
ViewState["ControlCount"] = count;
var btnAdd = new Button();
btnAdd.ID = "Add";
btnAdd.Text = "Add text box";
btnAdd.Click += new EventHandler(btnAdd_Click);
Controls.Add(btnAdd);
var btnPostBack = new Button();
btnPostBack.ID = "PostBack";
btnPostBack.Text = "Do PostBack";
Controls.Add(btnPostBack);
}
void btnAdd_Click(object sender, EventArgs e)
{
ViewState["ControlCount"] = (int)ViewState["ControlCount"] + 1;
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
// If I remove this RecreateChildControls call
// the collection lags behind each postback
// because the count is incremented in the btnAdd_Click event handler
// however, the values are not lost between postbacks
RecreateChildControls();
}
}

If you want to play with ASP.NET's custom controls, you have to play by its rule and its picky! When you start to play with the OnPreRender in a custom control, you know you're on the wrong track 90% of the time.
Generally, the best way to use the ViewState is to declare a property backed up by it, just like the standard ASP.NET controls do (.NET Reflector has been my teacher for years!). This way, it will be read and saved naturally during the event's lifecycle.
Here is a code that seems to do what you want, quite naturally, without any trick:
public class AddManyControl : CompositeControl
{
private void AddControl(int index)
{
var div = new HtmlGenericControl("div");
var textBox = new TextBox();
textBox.ID = "tb" + index;
div.Controls.Add(textBox);
Controls.AddAt(index, div);
}
protected override void CreateChildControls()
{
for (int i = 0; i < ControlsCount; i++)
{
AddControl(i);
}
var btnAdd = new Button();
btnAdd.ID = "Add";
btnAdd.Text = "Add text box";
btnAdd.Click += new EventHandler(btnAdd_Click);
Controls.Add(btnAdd);
var btnPostBack = new Button();
btnPostBack.ID = "PostBack";
btnPostBack.Text = "Do PostBack";
Controls.Add(btnPostBack);
}
private int ControlsCount
{
get
{
object o = ViewState["ControlCount"];
if (o != null)
return (int)o;
return 0;
}
set
{
ViewState["ControlCount"] = value;
}
}
void btnAdd_Click(object sender, EventArgs e)
{
int count = ControlsCount;
AddControl(count);
ControlsCount = count + 1;
}
}

I believe you have to add the control into the view state.