Add onclick event to buttonfield to gridview - asp.net

first you can see the gridview column properties as below picture

then add the RowCommand of grid view.

Code is below;

  protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)

        {

//this line is taking selected row value.

            int value = Convert.ToInt32(e.CommandArgument.ToString());

//this is shown for the data values exact what you want ..

            string  iStID = GridView1.Rows[value].Cells[1].Text;

//...then call to any other method to do your function ...

            

        }