Validation in WPF MaskedTextBox (SfMaskedEdit)

Input validation is based on the value of ValidationMode property. Enum values of this property are:

• LostFocus
• KeyPress
• HasError

KeyPress

When the ValidationMode is KeyPress, the validation is raised for each key press.

LostFocus

When the ValidationMode is LostFocus, the validation takes place when the control lost its focus.

HasError

This read only property is used to check whether the validation succeeds or not. It returns true once validation succeeds, or else set to be false.

xaml

<syncfusion:SfMaskedEdit x:Name="sfMaskedEdit" MaskType="Simple" Mask="00/00/0000" Value="14/11/2014" ValidationMode="LostFocus" LostFocus="sfMaskedEdit_LostFocus"/>

c#

private void sfMaskedEdit_LostFocus(object sender, RoutedEventArgs e)
{
    if (sfMaskedEdit.HasError)
    {
        MessageBox.Show("Please enter the correct date");
    }
}

Custom validation

In the SfMaskedEdit control, there is no event for the validation. The custom validation is based on the ValidationMode property by using the attached properties of Validation class. The HasError property is also used for source level validation.

Custom validation can be implemented by as follows:

1) Create a class inherited from ValidationRule.

2) Override the ValidationResult property and implement custom validation logic.

c#

public class NameValidator : ValidationRule
{
    public override ValidationResult Validate
	(object value, System.Globalization.CultureInfo cultureInfo)
        {
        	if (value == null)
                return new ValidationResult(false, "value cannot be empty.");
            else
            	{
                    if (value.ToString() == "__/__/____" || value.ToString().Contains("_")) 
                    	return new ValidationResult(false, "Name cannot be more than 8 characters long.");
            	}
            return ValidationResult.ValidResult;
        }
}

3) Set Triggers for KeyPress and LostFocus validation modes.

xaml

<Trigger Property="ValidationMode" Value="KeyPress">
    <Setter Property="Text">
        <Setter.Value>
            <Binding Path="Value" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
                <Binding.ValidationRules>
                    <local:NameValidator/>
                </Binding.ValidationRules>
            </Binding>
        </Setter.Value>
    </Setter>
</Trigger>