What I am trying to do is have a grid view with 3 "select" and I renamed them to edit , delete and details

and each one should redirect to a certain page

my question , how I can know which column or "Select" the user clicked

Thanks

Set the CommandName property of your buttons. Then add an event handler for the RowCommand event of the gridview:

protected void MyGrid_RowCommand(object sender, GridViewCommandEventArgs e)
{
  switch(e.CommandName)
  {
    case "SomeCommand":
      Response.Redirect("SomePage.aspx");
      break;
    case "OtherCommand":
      Respone.Redirect("OtherPage.aspx");
}

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