如何:覆盖依赖项属性的元数据

Question

如何覆盖默认依赖项属性元数据.例如; textbox的Text属性.我用这个代码

           class UCTextBox : TextBox
       {
           public UCTextBox()
        {
       var defaultMetadata = TextBox.TextProperty.GetMetadata(typeof(TextBox));

       TextBox.TextProperty.OverrideMetadata(typeof(UCTextBox),
     new          FrameworkPropertyMetadata(string.Empty,
        FrameworkPropertyMetadataOptions.Journal | 
     FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
        defaultMetadata.PropertyChangedCallback,
        new CoerceValueCallback(CoerceText)
        )); 
}

    private static object CoerceText(DependencyObject d, object value)
     {
     return   value.ToString().Replace(",","");           
    }

但这在两次运行中(获取,设置)

没有人可以帮助我!!!:(((

Answer 1

以下是从TextBox覆盖Text属性的元数据派生的类的示例:

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

public class MyTextBox : TextBox
{
    static MyTextBox()
    {
        TextBox.TextProperty.OverrideMetadata(typeof(MyTextBox),
            new FrameworkPropertyMetadata(string.Empty,
                FrameworkPropertyMetadataOptions.BindsTwoWayByDefault |
                FrameworkPropertyMetadataOptions.Journal,
                null, /* property changed callback */
                null, /* coerce value callback */
                true, /* is animation prohibited */
                UpdateSourceTrigger.LostFocus));
    }
}

请注意,覆盖位于static构造函数中,而不是普通构造函数.