CODEWITHSUNDEEP
c#asp.net
user1210868
user1210868

Reputation:

Dynamic generation of buttons with their click event

I am doing following code to generate dynamic buttons with their click event.

 protected void Button1_Click(object sender, EventArgs e)
{
    for (int i = 0; i < int.Parse(TextBox1.Text); i++)
    {
        Button bt = new Button();
        bt.Text = "ok";
        bt.Click += new EventHandler(bt_click);
        this.form1.Controls.Add(bt);

    }
}
protected void bt_click(object sender, EventArgs e)
{
    Label1.Text = "Clicked";
}

but i am not able to generate the click event of that dynamically generated button. Can any one help me?

Upvotes: 0

Views: 2470

Answers (5)

Azhar Khorasany
Azhar Khorasany

Reputation: 2709

My previous submission was on WinForms which I have deleted. Here is the one on asp.net

protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack)
    {
        for (int i = 0; i < int.Parse(TextBox1.Text); i++)
        {
            CreateButton(i);
        }
    }
}
protected void Button1_Click(object sender, EventArgs e)
{
}

protected void bt_click(object sender, EventArgs e)
{
    Button btn = sender as Button;
    Label1.Text = btn.Text + " Clicked";
}

private void CreateButton(int id)
{
    Button bt = new Button();
    bt.Text = "ok" + id.ToString();
    bt.Click += new EventHandler(bt_click);
    bt.ID = "btn" + id.ToString();
    this.Form.Controls.Add(bt);
}

Upvotes: 1

Nikola Radosavljević
Nikola Radosavljević

Reputation: 6911

For ASP.NET to be able to execute your event, control which triggered it should also exist on your page after postback. What is going on with your code looks like this:

  • page has several buttons you placed in design mode
  • you click button which generates new buttons
  • page loads again and looks for button you clicked, in the page
  • button is found, asp looks for event handler and executes it
  • new dynamic buttons are added and events attached, page renders again

It was all ok up till now, now problem occurs

  • you click button which was added dynamically
  • page loads again and looks for button you clicked (so it can find it's handler)
  • button is not found because it is not created yet. it was created dynamically to be rendered, and it wasn't created after postback at stage where asp is looking for it

General rule is that if you're adding controls dynamically and you want them to trigger events, you should do it latest in Page_Load. For more details please read ASP.NET Page Life Cycle Overview

Upvotes: 2

Ravi Gadag
Ravi Gadag

Reputation: 15881

you need to add this code in either page load or page_init event of page. then only you can access it. How to add controls dynamically asp.net 

protected void Page_Load()
{
    for (int i = 0; i < int.Parse(textBox1.Text); i++)
       {
          Button bt = new Button();
          bt.Text = "ok";
          bt.Click += new EventHandler(bt_click);
          this.Controls.Add(bt);
       }
}

Upvotes: 0

Henrik Gering
Henrik Gering

Reputation: 1891

I'm not sure if its your problem, but you might want to set the location property of eachbutton you add like:

bt.Location = new Point(25,i+55);

Upvotes: 0

Bolu
Bolu

Reputation: 8786

You need to set the position of those new buttons, or they will cover each other.

Upvotes: 0

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