获取某行的字段ID值(GridView模板列)

aspx页面

<asp:GridView runat="server" ID="grd" AutoGenerateColumns="false" DataKeyNames="leagueID" OnRowCommand="grd_RowCommand"  OnRowCreated="grd_RowCreated">
<Columns>
<asp:TemplateField HeaderText="我要加入">
                    <ItemStyle HorizontalAlign="Center" />
                    <ItemTemplate>
                        &nbsp;<asp:Button runat="server" ID="btnJoin" Text="加 入" CommandName="btnJoin" />
                    </ItemTemplate>
                 </asp:TemplateField>
</Columns>
</asp:GridView>

aspx.cs类文件

 protected void grd_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName == "btnJoin")
        {
                int index = Data.GetInt(e.CommandArgument);
                int iLeagueID = Data.GetInt(grd.DataKeys[index].Value);
                Response.Write("<script>alert('" + iLeagueID + "')</script>");
        }
    }

    protected void grd_RowCreated(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
                Button btnJoin = (Button)e.Row.FindControl("btnJoin");
                btnJoin.CommandArgument = e.Row.RowIndex.ToString();
        }
    }