回发后，GridView中RadioButtons的检查状态不会更改

Question

I have a Gridview control and I have placed a RadioButton in the itemtemplate. When I click a button I'm trying to get the checked property of the radio button. But When I click the checked property is always returning false. Please look into the below code and let me know where I'm making mistake.

aspx Code

<asp:GridView ID="gvDepartments" runat="server" AutoGenerateColumns="False" GridLines="None"AllowPaging="true" CssClass="mGrid" PagerStyle-CssClass="pgr" AlternatingRowStyle-CssClass="alt">
      <Columns> 
       <asp:TemplateField>
         <ItemTemplate>
                 <asp:RadioButton ID="rdbtn" runat="server" />
         </ItemTemplate>
       </asp:TemplateField>
      </Columns>
    </asp:GridView>
<asp:Label ID="lbl" runat="server"></asp:Label>
<asp:Button ID="btn" runat="server" Text="Save" OnClick="btn_Click" CssClass="button small"/>

Code Behind on button click

foreach (GridViewRow row in gvDepartments.Rows)
{
   if (row.RowType == DataControlRowType.DataRow)
    {
        RadioButton rd = (RadioButton)row.FindControl("rdbtn");
        lbl.Text += rd.Checked.ToString();// +rd1.Checked.ToString();
    }
}

Result will be False always in the label always. I'm using Ajaxcontroltoolkit in the application, Above controls are present in the update panel and I even tried to placing button and event in the triggers but the result is same. Please help.

Regards,
Nuthan AR

Answer 1

When do you assign and load the DataSource of the GridView ? Note that you should do that only if(!IsPostBack) and not on every postback. So use the Page.IsPostBack property .

So assuming that you're using Page_Load for this:

protected void Page_Load(Object sender, EventArgs e)
{
    if(!Page.IsPostBack)
    {
        DataBindGridView(); // method that assigns DataSource and calls DataBind
    }
}