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Validate Input and Play Error Sound


Product Version 2019.1.117
Product RadMaskedEditBox for WinForms


An example demonstrating how the RadMaskedEditBox control can be customized to validate the user input and play sound if the input is not according to the applied mask.


The RadMaskedEditBox is working with a mask provider to validate the input. The mask provider inside the control is used internally and one cannot call its Validate method outside of the context of the control. A possible solution is to create a separate mask provider instance solely responsible for validating the input and playing the error beep sound. The actual validation can be performed in the KeyDown event of the control.

The same result can be achieved with the other mask providers as well.

Form Code

public partial class Form1 : Form
    StandartMaskTextBoxProvider standartMaskProvider;

    public Form1()

        this.radMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Standard;
        this.radMaskedEditBox1.Mask = "##-##";

        this.standartMaskProvider = new StandartMaskTextBoxProvider(this.radMaskedEditBox1.Mask, this.radMaskedEditBox1.Culture, new RadMaskedEditBoxElement(), this.radMaskedEditBox1.AllowPromptAsInput, this.radMaskedEditBox1.PromptChar, this.radMaskedEditBox1.PasswordChar, false);

    private void radMaskedEditBox1_KeyDown(object sender, KeyEventArgs e)
        KeysConverter kc = new KeysConverter();
        string keyChar = kc.ConvertToString(e.KeyCode);

        bool isValid = this.standartMaskProvider.Validate(keyChar);
        if (!isValid)

Public Class Form1

    Private standartMaskProvider As StandartMaskTextBoxProvider

    Public Sub New()

        Me.radMaskedEditBox1.MaskType = Telerik.WinControls.UI.MaskType.Standard
        Me.radMaskedEditBox1.Mask = "##-##"
        Me.standartMaskProvider = New StandartMaskTextBoxProvider(Me.radMaskedEditBox1.Mask, Me.radMaskedEditBox1.Culture, New RadMaskedEditBoxElement(), Me.radMaskedEditBox1.AllowPromptAsInput, Me.radMaskedEditBox1.PromptChar, Me.radMaskedEditBox1.PasswordChar, False)
    End Sub

    Private Sub radMaskedEditBox1_KeyDown(ByVal sender As Object, ByVal e As KeyEventArgs)
        Dim kc As KeysConverter = New KeysConverter()
        Dim keyChar As String = kc.ConvertToString(e.KeyCode)
        Dim isValid As Boolean = Me.standartMaskProvider.Validate(keyChar)

        If Not isValid Then
        End If
    End Sub
End Class

See Also

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