WPF StringFormat on Label Content

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.