用于ErrorTemplate的不同的ErrorTemplate

Question

在我的应用程序中，我有一个ControlTemplate，用于显示TextBox的输入无效。ControlTemplate被定义为：

<ControlTemplate x:Key="TextBoxErrorTemplate" TargetType="Control">
    <Grid ClipToBounds="False">
        <Border BorderBrush="Red" BorderThickness="1" Margin="-1">
            <AdornedElementPlaceholder Name="adornedElement" />
        </Border>
        <Image HorizontalAlignment="Right" VerticalAlignment="Top"
               Width="16" Height="16" Margin="0,-9,-8,0" Source="pack://application:,,,/UI.Resources;component/Graphics/Error_16_16.png"
               ToolTip="{Binding ElementName=adornedElement, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}" />
    </Grid>
</ControlTemplate>

其用途是：

<TextBox Grid.Row="1" Margin="0,5"
         Text="{Binding UserGroup.Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}"
         Validation.ErrorTemplate="{StaticResource TextBoxErrorTemplate}"/>

UserGroup类实现了IDataErrorInfo-Interface。班上有一小部分人看起来是这样的：

public class UserGroup
{
    public string Name
    {
        get { return Get(() => Name); }
        set { Set(() => Name, value); }
    }

    public bool IsDuplicate
    {
        get { return Get(() => IsDuplicate); }
        set { Set(() => IsDuplicate, value); }
    }

    public bool IsSimilar
    {
        get { return Get(() => IsSimilar); }
        set { Set(() => IsSimilar, value);}
    }
}

IDataErrorInfo所需的getter的实现如下所示：

public string this[string columnName]
{
    get
    {
        string result = string.Empty;
        string namePropertyName = GetPropertyNameFromExpression(() => Name);
        string isDuplicatePropertyName = GetPropertyNameFromExpression(() => IsDuplicate);
        string isSimilarPropertyName = GetPropertyNameFromExpression(() => IsSimilar);

        if (columnName == namePropertyName)
        {
            if(IsSimilar)
            {
                result = "Be careful with similar group-names!";
                if (!Error.Contains(isSimilarPropertyName))
                {
                    Error += isSimilarPropertyName;
                }
            }
            else
            {
                Error = Error.Replace(isSimilarPropertyName, string.Empty);
            }

            if (IsDuplicate)
            {
                result = "Duplicate names are not allowed!";
                if (!Error.Contains(isDuplicatePropertyName))
                {
                    Error += isDuplicatePropertyName;
                }
            }           
            else
            {
                Error = Error.Replace(isDuplicatePropertyName, string.Empty);
            }
        }       
        return result;
    }
}

因此，如果IsSimilar或IsDuplicate为真，则将使用TextBoxErrorTemplate-ControlTemplate。

我想要的是，只有当TextBoxErrorTemplate等于true时，才应该使用IsDuplicate。

在IsSimilar等于true的情况下，我想使用以下ControlTemplate

<ControlTemplate x:Key="TextBoxWarningTemplate" TargetType="Control">
    <Grid ClipToBounds="False">
        <Border BorderBrush="Orange" BorderThickness="1" Margin="-1">
            <AdornedElementPlaceholder Name="adornedElement" />
        </Border>
        <Image HorizontalAlignment="Right" VerticalAlignment="Top"
               Width="16" Height="16" Margin="0,-9,-8,0" Source="pack://application:,,,/UI.Resources;component/Graphics/Warning_16_16.png"
               ToolTip="{Binding ElementName=adornedElement, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}" />
    </Grid>
</ControlTemplate>

有办法做到这一点吗？我的第一种方法是用一个TextBox覆盖Border，并且只显示IsSimilar是否是真的，但这看起来并不是很好……

我读过关于TemplateSelector的文章，但只在DataGridTemplateColumn的上下文中读过

Answer 1

我自己解决的。解决方案只有一个ControlTemplate，其中ImageSource和BorderBrush绑定到一个UserGroup属性，并在两个转换器中完成决策。

ControlTemplate看起来像：

 <ControlTemplate x:Key="TextBoxErrorTemplate" TargetType="Control">
    <Grid ClipToBounds="False">
        <Border BorderThickness="1" Margin="-1" 
                BorderBrush="{Binding DataContext.UserGroup, Converter={converters:UserGroupToBrushConverter}, 
                              RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}">
            <AdornedElementPlaceholder Name="adornedElement" />
        </Border>
        <Image HorizontalAlignment="Right" VerticalAlignment="Top"
               Width="16" Height="16" Margin="0,-9,-8,0" 
               Source="{Binding DataContext.UserGroup, Converter={converters:UserGroupToImageSourceConverter},
                        RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}"
               ToolTip="{Binding ElementName=adornedElement, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}" />
    </Grid>
</ControlTemplate>