try this...
protected void GridViewResults_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType==DataControlRowType.DataRow)
{
string str="";
str = e.Row.Cells["ID Column Index"].Text;
Label tempLabel = (Label)e.Row.Cells["ID Column Index"].FindControl("Label1")
if(tempLabel!=null)
str=tempLabel.Text;
CallMe(str);
}
}