http://forums.ext.net/showthread.php...791#post109791

am binding the RadioGroup based above link...
                           <ext:FormPanel runat="server" ID="formpanel1">
                                <Items>
                                    <ext:RadioGroup ID="RadioGroupBody" runat="server" FieldLabel="Body" LabelWidth="150"
                                        Width="400" ColumnsNumber="3">
                                        <DirectEvents>
                                            <Change OnEvent="RadioGroup_Change" />
                                        </DirectEvents>
                                    </ext:RadioGroup>
                                </Items>
                            </ext:FormPanel>
this is the way am binding...


 RadioGroupBody.Items.Add(new Radio
            {
                ID = "Text",
                IDMode = IDMode.Explicit,
                BoxLabel = "Text",
                InputValue = "Text",
                Checked = ResouceContentFormat == "Text" ? true : false
            });

            RadioGroupBody.Items.Add(new Radio
            {
                ID = "Url",
                IDMode = IDMode.Explicit,
                BoxLabel = "URL",
                InputValue = "Url",
                Checked = ResouceContentFormat == "Url" ? true : false
            });

            RadioGroupBody.Items.Add(new Radio
            {
                ID = "File",
                IDMode = IDMode.Explicit,
                BoxLabel = "Upload",
                InputValue = "File",
                Checked = ResouceContentFormat == "File" ? true : false
            });

            RadioGroupBody.AddTo(formpanel1);
the error will appearing Here...
protected void RadioGroup_Change(object sender, DirectEventArgs e)
    {
        RadioGroup rg = sender as RadioGroup;
        RadioGroupBody.Items.Count();

        X.Msg.Alert("Change", rg.CheckedItems[0].ID).Show();
    }
the Error message is

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index