Preventing RadMaskedEditBox from Losing Focus on Validation Failure
Environment
| Product Version | Product | Author |
|---|---|---|
| 2025.1.211 | RadMaskedEditBox for WinForms | Dinko Krastev |
Description
In scenarios where a RadMaskedEditBox is used with an Email MaskType, it's crucial to ensure the input is valid before allowing the user to move focus away from the control. This article demonstrates how to prevent focus loss from a RadMaskedEditBox when email validation fails.
Solution
To achieve this, handle the Validating event of the RadMaskedEditBox. Within the event handler, invoke the Validate() method of the EMailMaskTextBoxProvider, which is accessible via the Provider property of the MaskedEditBoxElement. If the validation fails, set the Cancel property of the System.ComponentModel.CancelEventArgs parameter to true to prevent focus change.
// Subscribe to the Validating event
this.radMaskedEditBox1.Validating += RadMaskedEditBox1_Validating;
// Validating event handler
private void RadMaskedEditBox1_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
// Perform the validation
bool isValid = ((EMailMaskTextBoxProvider)this.radMaskedEditBox1.MaskedEditBoxElement.Provider).Validate(this.radMaskedEditBox1.MaskedEditBoxElement.Text);
// If validation fails, cancel the event to prevent focus loss
if (!isValid)
{
e.Cancel = true;
}
}