MVVM Light中具有DependencyProperty的UserControl

Question

I have a UserControl that add a DependencyProperty for it .

    public const string TextValuePropertyName = "TextValue";
      public string TextValue
    {
        get
        {
            return (string)GetValue(TextValueProperty);
        }
        set
        {
            SetValue(TextValueProperty, value);
        }
    }
     public static readonly DependencyProperty TextValueProperty = DependencyProperty.Register(
        TextValuePropertyName,
        typeof(string),
        typeof(FormatUserControl),
        new UIPropertyMetadata());

and use it in another Usercontrol

       <local:FormatUserControl   TextValue="{Binding Subject,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"  />

When i use this don't set value for this property when i change Subject value?

Answer 1

Your FormatUserControl is the class and you should register the property for it not for the NumberFormatUserControl like this (I am not aware what is the relationship between the two user controls):

public static readonly DependencyProperty TextValueProperty = DependencyProperty.Register(
    TextValuePropertyName,
    typeof(string),
    typeof(FormatUserControl),
    new UIPropertyMetadata());