Which control caused the postback?

You can use this method to get the control that caused the postback:

/// <summary>/// Retrieves the control that caused the postback./// </summary>/// <param name="page"></param>/// <returns></returns>private Control GetControlThatCausedPostBack(Page page){    //initialize a control and set it to null    Control ctrl = null;    //get the event target name and find the control    string ctrlName = page.Request.Params.Get("__EVENTTARGET");    if (!String.IsNullOrEmpty(ctrlName))        ctrl = page.FindControl(ctrlName);    //return the control to the calling method    return ctrl;}

http://geekswithblogs.net/mahesh/archive/2006/06/27/83264.aspx

private string getPostBackControlName()    {        Control control = null;        //first we will check the "__EVENTTARGET" because if post back made by       the controls        //which used "_doPostBack" function also available in Request.Form collection.        string ctrlname = Page.Request.Params["__EVENTTARGET"];        if (ctrlname != null && ctrlname != String.Empty)        {            control = Page.FindControl(ctrlname);        }        // if __EVENTTARGET is null, the control is a button type and we need to        // iterate over the form collection to find it        else        {            string ctrlStr = String.Empty;            Control c = null;            foreach (string ctl in Page.Request.Form)            {                //handle ImageButton they having an additional "quasi-property" in their Id which identifies                //mouse x and y coordinates                if (ctl.EndsWith(".x") || ctl.EndsWith(".y"))                {                    ctrlStr = ctl.Substring(0, ctl.Length - 2);                    c = Page.FindControl(ctrlStr);                }                else                {                    c = Page.FindControl(ctl);                }                if (c is System.Web.UI.WebControls.Button ||                         c is System.Web.UI.WebControls.ImageButton)                {                    control = c;                    break;                }            }        }        if (control != null)            return control.ID;        else            return string.Empty;    }

This helps to find the name of control that caused postback in pageload.This helped me.Hope this helps someone else too

  <asp:Button ID="Button1" runat="server" Text="Button"  OnClientClick = "SetSource(this.id)" />   <asp:ImageButton ID="ImageButton1" runat="server"    OnClientClick = "SetSource(this.id)" />            <script type = "text/javascript">            function SetSource(SourceID)          {    var hidSourceID =    document.getElementById("<%=hidSourceID.ClientID%>");    hidSourceID.value = SourceID;    }    </script> on code behind you can get the ID of the function using : if (IsPostBack) {   string CtrlID = string.Empty;  if (Request.Form[hidSourceID.UniqueID] != null &&       Request.Form[hidSourceID.UniqueID] != string.Empty)    {     CtrlID = Request.Form[hidSourceID.UniqueID];   }}