Ajax.Asp.Net Tips and Tricks: Adding Dynamic Controls to UpdatePanel and Identifying what control has triggered the event.

Here is a cool technique on how to identify which control has triggered the UpdatePanel (when dynamic controls are added during runtime). Here we will use the Request Object to identify this.

Lets say we have updatePanel1

<div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="conditional">
  <ContentTemplate>
    <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
    <asp:Panel ID="Panel1" runat="server" Height="50px" Width="125px">
    </asp:Panel>
  </ContentTemplate>
</asp:UpdatePanel>
</div>

and during runtime we go and add dynamic buttons.... button1, button2 in the Panel1....

LinkButton button1 = new LinkButton();
button1.ID = "button1"
button1.Text = "button1"

LinkButton button2 = new LinkButton();
button2.ID = "button2"
button2.Text = "button2"

Panel1.Controls.Add(button1);
Panel1.Controls.Add(button2);

now we can identify which button is clicked, by looking at the Request Object and passing the key of the ScriptManager.ID:

protected override void CreateChildControls()
{
  base.CreateChildControls();
  if( ScriptManager1.IsInAsyncPostBack )
  {
    string fromWhere = Request[ScriptManager1.ID];
    Label1.Text = fromWhere;
  }
}
 

This will get the following wtring:
On Button1 click: UpdatePanel1|button1
On Button2 click: UpdatePanel1|button2

if we look carefully at the string  "UpdatePanel1|button1" we see that it has 2 parts, the ID of the UpdatePanel which got triggered and the ID of the control (ie. button1) which triggered the event.

So we can do something like this.....

protected override void CreateChildControls()
{
  base.CreateChildControls();
  if( ScriptManager1.IsInAsyncPostBack )
  {
    string fromWhere = Request[ScriptManager1.ID];   

    if( fromWhere.Contains("button1") )
    {
        //Do something here
    }
    else if (fromWhere.Contains("button2")
    {

        //Do something else....as you wish....
    }
  }
}