wpf 条件 XAML 绑定
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Conditional XAML-Binding
提问by SeToY
I'd like to create a window title similar to Microsoft Outlook's one.
我想创建一个类似于 Microsoft Outlook 的窗口标题。
For that, I've created the following binding:
为此，我创建了以下绑定：
<MultiBinding StringFormat="{}{0} - Message ({1})}">
<Binding ElementName="txtSubject" Path="Text" />
<Binding ElementName="biSendAsHtml">****</Binding>
</MultiBinding>
Now I'd like to know how I can make the second binding conditional. Such as when biSendAsHtml.IsCheckedequals truedisplay HTMLelse display Plain Text.
现在我想知道如何使第二个绑定有条件。比如当biSendAsHtml.IsCheckedequalstrue显示HTMLelse 显示纯文本。
回答by Rohit Vats
Create a IValueConverterand use it in your second binding -
创建一个IValueConverter并在您的第二个绑定中使用它 -
public class MyConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
return (bool)value ? "HTML" : "Your Text";
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
Here goes your XAML -
这是你的 XAML -
<MultiBinding StringFormat="{}{0} - Message ({1})}">
<Binding ElementName="txtSubject" Path="Text" />
<Binding ElementName="biSendAsHtml" Path="IsChecked"
Converter="{StaticResource Myconverter}"/>
</MultiBinding>
回答by Duncan Matheson
I'm not sure how you think sa_ddam213's answer is elegant, it's just scary. The converter, like RV1987 suggested, is the correct approach, but you can be a lot smarter.
我不确定你认为 sa_ddam213 的答案是优雅的，它只是可怕。转换器，就像 RV1987 建议的那样，是正确的方法，但你可以更聪明。
Create a converter which takes a bool and converts it into options defined in the Converter definition.
创建一个转换器，它接受一个布尔值并将其转换为转换器定义中定义的选项。
public class BoolToObjectConverter : IValueConverter
{
public object TrueValue { get; set; }
public object FalseValue { get; set; }
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return Convert.ToBoolean(value) ? TrueValue : FalseValue;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
Define the Converter:
定义转换器：
<local:BoolToObjectConverter x:Key="SendAsHtmlBoolToTextConverter"
TrueValue="HTML"
FalseValue="Plain Text"/>
And use it:
并使用它：
<MultiBinding StringFormat="{}{0} - Message ({1})}">
<Binding ElementName="txtSubject" Path="Text" />
<Binding ElementName="biSendAsHtml" Path="IsChecked"
Converter="{StaticResource SendAsHtmlBoolToTextConverter}"/>
</MultiBinding>
If you want you could even make TrueValue and FalseValue DependencyProperties to support Binding.
如果您愿意，您甚至可以使 TrueValue 和 FalseValue DependencyProperties 支持绑定。
