RadRadioButtonList RequiredFieldValidator

[RBarnes]

Validator text shows as required, however the message on the validator doesn't show in the asp:ValidationSummary control.

 

[Rumen]

Can you try the following example based on the Validation on the Server article:

ASPX

        <telerik:RadRadioButtonList ID="YourRadRadioButtonListID" runat="server" ValidationGroup="YourValidationGroup" AutoPostBack="false">
            <Items>
                <telerik:ButtonListItem Text="Item1" Value="Item1" />
                <telerik:ButtonListItem Text="Item2" Value="Item2" />
                <telerik:ButtonListItem Text="Item3" Value="Item3" />
            </Items>
        </telerik:RadRadioButtonList>

        <asp:RequiredFieldValidator ID="YourRequiredFieldValidatorID" runat="server" InitialValue="" 
            ControlToValidate="YourRadRadioButtonListID" ErrorMessage="Selection is required." ValidationGroup="YourValidationGroup"
            >
        </asp:RequiredFieldValidator>
        <asp:ValidationSummary ID="ValidationSummary1" runat="server"
            DisplayMode="BulletList" ShowMessageBox="false" ShowSummary="true" ValidationGroup="YourValidationGroup" />

        <asp:Button ID="SubmitButton" runat="server" Text="Submit" ValidationGroup="YourValidationGroup"
            OnClick="SubmitButton_Click" />

 

ASPX.CS

public partial class _Default : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
        }
    }



    protected void SubmitButton_Click(object sender, EventArgs e)
    {

    }
}

Some other tips:

When working with ASP.NET Web Forms and Telerik's RadRadioButtonList in combination with a RequiredFieldValidator, there are a few common issues that can lead to the validator's message not displaying in the ValidationSummary control. Here's a checklist to troubleshoot and ensure proper setup:

1. Correct ControlToValidate Property
Ensure that the RequiredFieldValidator is correctly pointing to the RadRadioButtonList's ID.

<telerik:RadRadioButtonList ID="YourRadRadioButtonListID" runat="server">
    <!-- List Items here -->
</telerik:RadRadioButtonList>

<asp:RequiredFieldValidator ID="YourRequiredFieldValidatorID" runat="server"
    ControlToValidate="YourRadRadioButtonListID" ErrorMessage="Selection is required."
    InitialValue="">
</asp:RequiredFieldValidator>

2. Setting the InitialValue
The RequiredFieldValidator should have its InitialValue property set to an appropriate value (often an empty string) that represents the unselected state.

3. Include ValidationSummary
Ensure that the ValidationSummary control is properly added to your page.

<asp:ValidationSummary ID="ValidationSummary1" runat="server" 
    DisplayMode="BulletList" ShowMessageBox="false" ShowSummary="true" />

4. Grouping Validators (Optional)
If you are using validation groups, make sure that both the RequiredFieldValidator and the ValidationSummary are set to the same ValidationGroup.

<asp:RequiredFieldValidator ID="ValidatorID" runat="server"
    ControlToValidate="YourRadRadioButtonListID" ErrorMessage="Selection is required"
    ValidationGroup="YourValidationGroup" />

<asp:ValidationSummary ID="ValidationSummary1" runat="server" 
    ValidationGroup="YourValidationGroup" ... />

5. Page Validation Settings
Check if the validation is triggered properly. For instance, this is often done with a submit button. Make sure the submit button is set to validate the page (the default behavior).

<asp:Button ID="SubmitButton" runat="server" Text="Submit" 
    OnClick="SubmitButton_Click" />

6. JavaScript Conflicts
Sometimes, JavaScript or AJAX settings may interfere with the validation. Check if there are any scripts that might prevent the validation summary from updating. Check for JS errors in the DevTools (F12) console.

7. UpdatePanel Issues
If your controls are inside an UpdatePanel, ensure that the validation and update mechanism is correctly configured.

8. Server-Side Validation Check
On the server-side event (e.g., button click), ensure that you check Page.IsValid before processing form data.

 

[RBarnes]

ShowMessageBox="false" ShowSummary="true"
change to
ShowMessageBox="true" ShowSummary="false"
 
Summary is not shown.  
 
Test:
        <telerik:RadTextBox ID="txtTest" runat="server" Columns="10">
        </telerik:RadTextBox>
        <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtTest" InitialValue=""
            Display="Static" ErrorMessage="Test Value is required" Text="*" ForeColor="Red" Enabled="true"></asp:RequiredFieldValidator>

        <telerik:RadRadioButtonList ID="YourRadRadioButtonListID" runat="server" AutoPostBack="false">
            <Items>
                <telerik:ButtonListItem Text="Item1" Value="Item1" />
                <telerik:ButtonListItem Text="Item2" Value="Item2" />
                <telerik:ButtonListItem Text="Item3" Value="Item3" />
            </Items>
        </telerik:RadRadioButtonList>

        <asp:RequiredFieldValidator ID="YourRequiredFieldValidatorID" runat="server" InitialValue="" Display="Static"
            ControlToValidate="YourRadRadioButtonListID" ErrorMessage="Selection is required." Text="*" >
        </asp:RequiredFieldValidator>
        <asp:ValidationSummary ID="ValidationSummary1" runat="server"
            DisplayMode="BulletList" ShowMessageBox="true" ShowSummary="false"  />
        <asp:Button ID="SubmitButton" runat="server" Text="Submit" />
 
Nore is the text shown for YourRequiredFieldValidatorID

[Rumen]

I was able to repro the issue, and to fix it I suggest using a custom validator that will show the ValidationSummary dialog when the error occurs:

        <telerik:RadRadioButtonList RenderMode="Classic" ID="YourRadRadioButtonListID" runat="server" ValidationGroup="YourValidationGroup" AutoPostBack="false" CausesValidation="true">
            <Items>
                <telerik:ButtonListItem Text="Item1" Value="Item1" />
                <telerik:ButtonListItem Text="Item2" Value="Item2" />
                <telerik:ButtonListItem Text="Item3" Value="Item3" />
            </Items>
        </telerik:RadRadioButtonList>

        <asp:CustomValidator ID="CustomValidator1" runat="server" ControlToValidate="YourRadRadioButtonListID" ValidateEmptyText="true" ErrorMessage="Item selection is required" ForeColor="Red" ValidationGroup="YourValidationGroup"
            ClientValidationFunction="customValidationFunction"></asp:CustomValidator>
        <script>
            function customValidationFunction(sender, args) {
                var rarioButtonList = $find(sender.controltovalidate);
                if (rarioButtonList && rarioButtonList.get_selectedIndex() < 0) {
                    args.IsValid = false;
                }
            }
        </script>

        <asp:ValidationSummary ID="ValidationSummary1" runat="server" Style="border: 1px solid red; width: 100px; height: 100px;"
            DisplayMode="SingleParagraph" ShowMessageBox="true" ShowSummary="false" ValidationGroup="YourValidationGroup" />

        <telerik:RadButton ID="SubmitButton" runat="server" Text="Submit" ValidationGroup="YourValidationGroup" ValidateRequestMode="Enabled"
            CausesValidation="true" />