checkbox single selection with rowdatabound in girdview

 protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
     
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                string strScript = "uncheckOthers(" + ((CheckBox)e.Row.Cells[0].FindControl("CheckBox1")).ClientID + ");";
                ((CheckBox)e.Row.Cells[0].FindControl("CheckBox1")).Attributes.Add("onclick", strScript);
            }
  }

protected void GridView1_PageIndexChanged(object sender, EventArgs e)
    {
        CheckBox ch = ((CheckBox)GridView1.SelectedRow.Cells[0].FindControl("CheckBox1"));
        ch.Checked = true;
    }