从WPF中的代码设置验证错误模板 [英] Setting Validation error template from code in WPF

问题描述

我的WPF应用程序中有一个TextBox.我为验证错误定义了一个ControlTemplate，如下所示:

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

<ControlTemplate x:Key="validationTemplate">
    <DockPanel LastChildFill="True">
         <TextBlock DockPanel.Dock="Bottom"  Text="Invalid Input: "></TextBlock>
                 <AdornedElementPlaceholder />
    </DockPanel>
</ControlTemplate>

我的文本框如下:

<TextBox Validation.ErrorTemplate="{StaticResource validationTemplate}">                                              
    <TextBox.Text>
        <Binding Path="TEXT1" ValidatesOnDataErrors="True" validatesOnExceptions="True">
         </Binding>
    </TextBox.Text>
</TextBox>

现在，如果我的文本框已添加ValidationRule，然后在此进行验证，则错误模板将正确应用.但是由于其他一些问题，我无法做到这一点.

Now if my TextBox is added ValidationRule and then I validate there, the error template applies correctly. But I cant do that because of some other problem.

因此，我必须在PreviewLostKeyboardFocus中验证TextBox的内容.我正在验证TextBox.现在，我想在后面的代码中为TextBox设置错误模板，但是我无法做到！

So I have to validate the content of TextBox in PreviewLostKeyboardFocus. I am validating the TextBox. Now I want to set the error template for the TextBox in code behind but I am unable to do it !!

我尝试了此操作，但无法按预期工作::

I tried this but it does not work as intented::

private void blockTextBox_PreviewLostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
    {
        TextBox txtBox = sender as TextBox;
        txtBox.Template = this.FindResource("validationTemplate") as ControlTemplate;

        //this behaves strange; it removes the TextBox and places the ErrorTemplate. 
       //I want it to behave like the way WPF does internally wherein it places 
       //the error template around TExtBox
    }

问题1:我想知道如何将错误模板添加到TextBox

Question 1: I want to know how to add the error template to TextBox

问题2:我想知道如何从代码中设置控制模板的错误消息.例如，我想将默认错误消息无效输入:"更改为无效输入:请输入正确的输入".

我只想在代码后面做上述事情！！！！

Question 2: I want to know how do I set the error message of the control template from code. Like for example, I want to change the default error message "Invalid Input: " to "Invalid Input: Please enter correct input".

I want to do the above mentioned things in code behind only !!!!

问题是如何从Validation.HasError后面的代码中将其设置为true，因为我没有使用任何Validator. (或者我应该从应用ValidationTemplate后面的代码中设置什么?)

The problem is how do I set from code behind Validation.HasError as true because I am not using any Validator. (or what should I set from code behind that ValidationTemplate gets applied ?? ))

我正在执行XML绑定，因此无法实现IDataErrorInfo！我只想从后面的代码中实现！有没有一种方法可以从??后面的代码中设置Validation.HasError?

I am doing XML binding so there is no way I can implement IDataErrorInfo !! I want to achieve this from code behind only!! Is there a way to set Validation.HasError from code behind ??

推荐答案

要在后面的代码中设置"Validation.HasError"，您可以使用Validation.MarkInvalid方法

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);
}

要取消设置您使用的值

Validation.ClearInvalid

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