问题
I am trying to display some label with MultiBinding with Binding on StringFormat.
Like that:
<Label.Content>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{Binding LabelStringFormat, Source={DynamicResource Texts}}">
<Binding Path="Lib1" />
<Binding Path="Lib2" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</Label.Content>
LabelStringFormat can be something like "[{0}/{1}]" or something like that. It is known in build but must be used from Resource.
But when I use something like code above, I get error:
A 'Binding' cannot be set on the 'StringFormat' property of type 'MultiBinding'. A 'Binding' can only be set on a DependencyProperty of a DependencyObject.
I can use binding on Content and create string in ViewModel, but it is unnoticed when there is more labels like this one.
Thanks Jakub
SOLUTION:
Use Convertor:
public class StringMultiValueConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return string.Format(values.Last() as string, values);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
In WPF add convertor to Resources:
<UserControl.Resources>
<ResourceDictionary>
<myComponents:StringMultiValueConverter x:Key="stringMultiValueConverter"/>
</ResourceDictionary>
</UserControl.Resources>
In Label add:
<Label.Content>
<TextBlock>
<TextBlock.Text>
<MultiBinding Converter="{StaticResource stringMultiValueConverter}">
<Binding Path="Lib1" />
<Binding Path="Lib2" />
<Binding Path="LabelStringFormat" Source="{Dynamic Texts}"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</Label.Content>
This work when string format is last param of Multibinding.
回答1:
Just add the "LabelStringFormat" as a parameter of the multi-binding:
<MultiBinding>
<Binding Path="Lib1" />
<Binding Path="Lib2" />
<Binding Path="LabelStringFormat" Source="{DynamicResource Texts}" />
</MultiBinding>
Do the formatting from your IValueConverter using String.Format((string)values[2], values[0], values[1])
.
回答2:
I don't think you need to use a Binding on the MultiBinding.StringFormat property. Instead, can you do something like this?
<Label.Content>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{DynamicResource Texts.LabelStringFormat}">
<Binding Path="Lib1" />
<Binding Path="Lib2" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</Label.Content>
来源:https://stackoverflow.com/questions/25247992/multibinding-with-binding-stringformat