Setting Validation error template from code in WPF

Question

I have a TextBox in my WPF app. I have defined a ControlTemplate for validation error as follows:

Answer 1

Validation.SetErrorTemplate(txtBox, this.FindResource("validationTemplate") as ControlTemplate);

Answer 2

For your first question. You can set the ErrorTemplate from code behind like.

    public MainWindow()
    {
        InitializeComponent();

        var template = this.FindResource("validationTemplate") as ControlTemplate;
        Validation.SetErrorTemplate(this.textBox1, template);
     }

Edit: For your second question. Please refer the following sample. sites.google.com/site/html5tutorials/ValidationErrorText.zip

Answer 3

Thanks to for the wonderful link he suggested me.My code goes somewhat this way

String errorMessage = GetFormattedErrorMessage(toolTip.Range, range);
ValidationError validationError = new ValidationError(new DummyValidator(),
txtBox.GetBindingExpression(TextBox.TextProperty));
Validation.MarkInvalid(txtBox.GetBindingExpression(TextBox.TextProperty), validationError);
validationError.ErrorContent = errorMessage;
Validation.SetErrorTemplate(txtBox, GetErrorTemplate(errorMessage));

Answer 4

To set "Validation.HasError" in code behind you can use the Validation.MarkInvalid method

private void blockTextBox_PreviewLostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e) 
{ 
    TextBox txtBox = sender as TextBox;
    //...
    BindingExpression bindingExpression =
        BindingOperations.GetBindingExpression(txtBox, TextBox.TextProperty);

    BindingExpressionBase bindingExpressionBase = 
        BindingOperations.GetBindingExpressionBase(txtBox, TextBox.TextProperty);

    ValidationError validationError =
        new ValidationError(new ExceptionValidationRule(), bindingExpression);

    Validation.MarkInvalid(bindingExpressionBase, validationError);
}

To unset the value you use

Validation.ClearInvalid