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Linking to StringFormat on a custom control

I'm trying to use a custom control in a WPF application, and I have some problem using StringFormat bindings.

The problem is easy to reproduce. First create a WPF application and name it "TemplateBindingTest". There, add a custom ViewModel with only one property (Text) and assign it to the DataContext window. Set the Text property to "Hello World!"

Now add the custom control to the solution. A user control is as simple as it can get:

using System.Windows;
using System.Windows.Controls;

namespace TemplateBindingTest
{
    public class CustomControl : Control
    {
        static CustomControl()
        {
            TextProperty = DependencyProperty.Register(
                "Text",
                typeof(object),
                typeof(CustomControl),
                new FrameworkPropertyMetadata(null));

            DefaultStyleKeyProperty.OverrideMetadata(typeof(CustomControl), new FrameworkPropertyMetadata(typeof(CustomControl)));
        }

        public static DependencyProperty TextProperty;

        public object Text
        {
            get
            {
                return this.GetValue(TextProperty);
            }

            set
            {
                SetValue(TextProperty, value);
            }
        }
    }
}

Visual Studio "" generic.xaml. :

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:TemplateBindingTest">

    <Style TargetType="{x:Type local:CustomControl}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:CustomControl}">
                    <TextBlock Text="{TemplateBinding Text}" />
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

Text, StringFormat. TextBlock, , :

<Window x:Class="TemplateBindingTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:TemplateBindingTest="clr-namespace:TemplateBindingTest" Title="MainWindow" Height="350" Width="525">
<StackPanel>
    <TemplateBindingTest:CustomControl Text="{Binding Path=Text, StringFormat=Test1: {0}}"/>
    <TextBlock Text="{Binding Path=Text, StringFormat=Test2: {0}}" />
</StackPanel>

, , aaaaand... , :

, !

Test2: Hello World!

StringFormat . VS . ?

: .

, TemplateBinding . .

-, , Content Button:

<Button Content="{Binding Path=Text, StringFormat=Test3: {0}}" />

, ? Reflector StringFormat BindingBase. "" , DetermineEffectiveStringFormat. :

internal void DetermineEffectiveStringFormat()
{
    Type propertyType = this.TargetProperty.PropertyType;
    if (propertyType == typeof(string))
    {
         // Do some checks then assign the _effectiveStringFormat field
    }
}

. effectiveStringFormat - , . , DependencyProperty String (, Button Content, Object).

? , , , , Button, , , .

, ? , WPF, " ". , , , XAML, :

using System.Windows;
using System.Windows.Controls;

namespace TemplateBindingTest
{
    public class CustomControl : Control
    {
        static CustomControl()
        {
            TextProperty = DependencyProperty.Register(
                "Text",
                typeof(string),
                typeof(CustomControl),
                new FrameworkPropertyMetadata(null, Callback));

            HeaderProperty = DependencyProperty.Register(
                "Header",
                typeof(object),
                typeof(CustomControl),
                new FrameworkPropertyMetadata(null));

            DefaultStyleKeyProperty.OverrideMetadata(typeof(CustomControl), new FrameworkPropertyMetadata(typeof(CustomControl)));
        }

        static void Callback(DependencyObject obj, DependencyPropertyChangedEventArgs e)
        {
            obj.SetValue(HeaderProperty, e.NewValue);
        }

        public static DependencyProperty TextProperty;
        public static DependencyProperty HeaderProperty;

        public object Header
        {
            get
            {
                return this.GetValue(HeaderProperty);
            }

            set
            {
                SetValue(HeaderProperty, value);
            }
        }

        public string Text
        {
            set
            {
                SetValue(TextProperty, value);
            }
        }
    }
}

Header - , TemplateBinding. Text, StringFormat, String, Header . , :

  • Header Text , Text Header. getter Text, , , - DependencyProperty (GetValue(TextProperty)).
  • , - Header, Text, .

, . , . , StringFormat.

+5
2

StringFormat string, Text object, StringFormat .

+2

StringFormat Converter TemplateBinding. .

+6

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