how to popup confirm box?

There is many way you can handle it but this is a easy way :

Java Script Function :

function confirmSubmit() {
      var agree=confirm("Are You Sure ?");
      if (agree)
       return true ;
      else
       return false ;
    }

In Grid view :

OnClientClick="return confirmSubmit()"

For confirm Box You can use javascript popup box.

Write:-
Alert.show("message"); or
ClientScript.RegisterStartupScript(this.GetType(), "myalert", "alert("Message");", true);

or you can call a java script function..............

on your asp button put the javascript function on OnClientClick event.

<asp:button id="btnDel" runat="server" text="DELETE" onclientclick="delFunc()" xmlns:asp="#unknown" />

in javascript use jquery

/*this is javascript*/
function delFunc()
{
 if(confirm("Are you sure want to delete?"))
 {
  .........
   call the code behind function/method using jquery.ajax();
  .........
 }
}

add following code to your gridview

<asp:TemplateField HeaderText="DELETE">
                                <ItemTemplate>
                                    <asp:LinkButton ID="LinkButton1" CommandArgument='<%# Eval("Primary_Key") %>' CommandName="Delete"
                                        runat="server" ForeColor="Red">
                                    Delete</asp:LinkButton>
                                </ItemTemplate>
                            </asp:TemplateField>

i hope it will solve your problem.

You can use the javascript alert command or use confirmbuttonextender af the ajaxcontroltoolkit. you can also make your own popup by making a div and place a message and buttons. Or u can also use modal popup extender to create your own popup. For your reference:

http://www.asp.net/ajaxlibrary/AjaxControlToolkitSampleSite/[^]

Best regards,
Eduard

Try
Confirm Box In Asp.net[^] having similar question with answers.
or navigate given link
Message Box in ASP.NET 2.0[^]
and CP article-[ Buttons, Message Box, and Confirm Box in ASP.NET 3.5 ][^]

Hi,
refer This Links....

http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/ConfirmButton/ConfirmButton.aspx[^]