WPF StringFormat on Label Content

I want to format my string binding as Amount is X where X is a property bound to a label.

I've seen many examples but the following doesn't work:

<Label Content="{Binding Path=MaxLevelofInvestment, 
   StringFormat='Amount is {0}'}" />

I've also tried these combinations:

StringFormat=Amount is {0}
StringFormat='Amount is {}{0}'
StringFormat='Amount is \{0\}'

I even tried changing the binding property's datatype to int, stringand double. Nothing seems to work. This is a very common use case but doesn't seem to be supported.

The reason this doesn't work is that the Label.Content property is of type Object, and Binding.StringFormat is only used when binding to a property of type String.

What is happening is:

1. The Binding is boxing your MaxLevelOfInvestment value and storing it the Label.Content property as a boxed decimal value.
2. The Label control has a template that includes a ContentPresenter.
3. Since ContentTemplate is not set, ContentPresenter looks for a DataTemplate defined for the Decimal type. When it finds none, it uses a default template.
4. The default template used by the ContentPresenter presents strings by using the label's ContentStringFormat property.

Two solutions are possible:

• Use Label.ContentStringFormat instead of Binding.StringFormat, or
• Use a String property such as TextBlock.Text instead of Label.Content

Here is how to use Label.ContentStringFormat:

<Label Content="{Binding Path=MaxLevelofInvestment}" ContentStringFormat="Amount is {0}" />

Here is how to use a TextBlock:

<TextBlock Text="{Binding Path=MaxLevelofInvestment, StringFormat='Amount is {0}'}" />

Note: For simplicity I omitted one detail in the above explanation: The ContentPresenter actually uses its own Template and StringFormat properties, but during loading these are automatically template-bound to the ContentTemplate and ContentStringFormat properties of the Label, so it seems as if the ContentPresenter is actually using the Label's properties.

Make a universal StringFormatConverter : IValueConverter. Pass your format string as ConverterParameter.

Label Content="{Binding Amount, Converter={...myConverter}, ConverterParameter='Amount is {0}'"

Also, make StringFormatMultiConverter : IMultiValueConverter when you need more than one object in format string, for instance, Completed {0} tasks out of {1}.

I just checked and for some reason it doesn't work with the Label, probably because it uses a ContentPresenter for the Content property internally. You can use a TextBlock instead and that will work. You could also put the TextBlock excerpt below in the content of a Label if you need to inherit styling, behaviour etc.

<TextBlock Text="{Binding Path=MaxLevelofInvestment, StringFormat='Amount is \{0\}'} />

Try using a converter....

<myconverters:MyConverter x:Key="MyConverter"/>


<Label Content="{Binding Path=MaxLevelofInvestment, Converter={StaticResource MyConverter"} />


public class MyConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return String.Format("Amount is {0}", value);
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value;
    }
}

You can use this below

<Label Content="{Binding Content, StringFormat='Page Data> {0}'}" />

"Content" is a binding variable and between the single quotes type your text. {0} where the Content data will be inserted.