WPF UserControl的ValidationRule触发了，但是这个TextBox的默认的ErrorTemplate没有看到红框

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2012-02-20 09:31:58

我创建了一个UserControl工程，里面有个TextBox，绑定了一个ValidationRule，然后我在另一个wpf窗体程序中插入了这个UserControl，调试发现Textbox的ValidationRule触发了，但是默认的红框没有出现。

如果我把UserControl基类改为Window，单独ShowDialog，红框是有的。

相关代码：



<UserControl

	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

	xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

	xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

	mc:Ignorable="d"

	x:Class="UserControlValidationDemo.UserControl1"

    xmlns:UserControlValidationDemo_ValidationRules="clr-namespace:UserControlValidationDemo.ValidationRules"

    xmlns:UserControlValidationDemo_ViewModels="clr-namespace:UserControlValidationDemo.ViewModels"

	x:Name="UserControl"

	d:DesignWidth="640" d:DesignHeight="480">

	<UserControl.Resources>

        <UserControlValidationDemo_ViewModels:MainViewModel x:Key="MainViewModelDataSource" d:IsDataSource="True"/>

    </UserControl.Resources>

    <UserControl.DataContext>

        <Binding Mode="OneWay" Source="{StaticResource MainViewModelDataSource}"/>

    </UserControl.DataContext>

    

    <Grid x:Name="LayoutRoot" Background="White">

		<TextBox HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Top" x:Name="txtTest">

            <TextBox.Text>

                <Binding Path="Collection[0].Property1" UpdateSourceTrigger="PropertyChanged">

                    <Binding.ValidationRules>

                        <UserControlValidationDemo_ValidationRules:TestValidationRule />

                    </Binding.ValidationRules>

                </Binding>

            </TextBox.Text>

        </TextBox>

	</Grid>

</UserControl>

namespace UserControlValidationDemo.ValidationRules
{
public class TestValidationRule : ValidationRule
{
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
if (GlobalDefinition.MainWnd is UserControl)
{
object t = Validation.GetErrorTemplate((GlobalDefinition.MainWnd as UserControl1).txtTest);
object e = Validation.GetErrors((GlobalDefinition.MainWnd as UserControl1).txtTest);

return new ValidationResult(false, "This is failed validation.");
}
else if (GlobalDefinition.MainWnd is Window)
{
object t = Validation.GetErrorTemplate((GlobalDefinition.MainWnd as Window1).txtTest);
object e = Validation.GetErrors((GlobalDefinition.MainWnd as Window1).txtTest);

return new ValidationResult(false, "This is failed validation.");
}

return new ValidationResult(false, "This is failed validation.");
}
}
}

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