如何将文本框绑定到WPF中的类的字段？

Question

I am trying to create a custom property editor for vector value like this:

 public struct Float4
 {
      public float x,y,z,w;
 }

In some object, it will have a property like this:

public class SomeEntity : INotifyPropertyChanged
{
      private Float4 prop;
      [Category("Property")]
      [Editor(typeof(VectorEditor),typeof(PropertyValueEditor)]
      public Float4 Prop
      {
            get{return prop;}
            set{prop = value ; NotifyPropertyChanged("prop");}
      }  
}

(I am using the WpfPropertyGrid from here )

VectorEditor uses a DataTemplate like this:

<DataTemplate x:Key="VectorEditorTemplate">
    <DataTemplate.Resources>
        <!--first use a ObjectDataProvider to get a `Type`-->
        <ObjectDataProvider MethodName="GetType" ObjectType="{x:Type local:Float4}" x:Key='VectorType' >
        </ObjectDataProvider>
        <local:GetFieldsConverter x:Key="GetFieldsConverter" />
    </DataTemplate.Resources>         

    <!--then use a Converter to create a ObservableCollection of `FieldInfo` from `Type`-->
    <ItemsControl ItemsSource="{Binding Source={StaticResource VectorType},Converter={StaticResource GetFieldsConverter}}">
            <ItemsControl.Resources>
            <!-- this Converter will provider field name-->
                <local:GetFieldNameConverter x:Key="GetFieldNameConverter"/>
            </ItemsControl.Resources>
            <!-- Other Elements -->
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <DockPanel HorizontalAlignment="Stretch">
                        <TextBlock DockPanel.Dock='Left' Text="{Binding Converter={StaticResource GetFieldNameConverter}}" Width="25" />
                        <TextBox HorizontalAlignment="Stretch" Text="{Binding Path=Value}"/>
                    </DockPanel>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
</DataTemplate>

In this case, the Path in TextBox.Text is setted to Value , since it is a template, it doesn't know which field this Item is associated with.

So, how to make it associated with the field? and binding to it, so when this TextBox's value changed, it can raise a PropertyChanged event to the object which contains the Float4 .

Answer 1

There is at least two things that will prevent usage of your Float4 type in WPF:

• it's a value type

• the members are not properties but fields

So I fear you'll have to use a proxy for your values:

public class Float4Proxy : INotifyPropertyChanged
{
    private Float4 float4;

    public float X
    {
        get { return float4.x; }
        set
        {
            if (value != float4.x)
            {
                float4.x = value;
                PropertyChanged(this, new PropertyChangedEventArgs("X"));
            }
        }
    }

    ...
}

And in your XAML you'll be able to do such two-way bindings:

<TextBox HorizontalAlignment="Stretch" Text="{Binding Path=Value.X}"/>