Question

我正在编写两个依赖项属性，并且我在VS11的设计窗口中不断收到“[Property]已经由'FrameworkElement'注册”错误。这是我的代码片段

        public static readonly DependencyProperty IsEditingNumberProperty =
        DependencyProperty.Register("IsEditingNumbers", typeof(bool), typeof(FrameworkElement),
        new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender));

问题似乎是第3个参数（所有者参数typeof（FrameworkElement））。如果我将第3个参数设置为包含两个依赖项属性的类，则错误消失，但我不能直接使用xaml中的属性。在使用之前，我必须为每个依赖属性添加所有权。

实际上，它确实正确渲染，但只有在我第一次打开它时才会渲染。第一次渲染后，它会立即给我一个例外。在运行时，它似乎完美无缺。

我做错了什么，有没有办法摆脱这个恼人的错误？

----编辑-----

这是我的自定义类（包括2个依赖属性）：

public partial class EditableTextBox : UserControl
{
    #region Dependency Properties
    public static readonly DependencyProperty IsEditingNumberProperty =
        DependencyProperty.Register("IsEditingNumber", typeof(bool), typeof(FrameworkElement),
        new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender));

    public static readonly DependencyProperty TextProperty =
        DependencyProperty.Register("Text", typeof(string), typeof(FrameworkElement),
        new FrameworkPropertyMetadata("0", FrameworkPropertyMetadataOptions.AffectsRender) 
        { 
            CoerceValueCallback = new CoerceValueCallback((sender,value) =>
                {
                    return expressionRestaraint.Match((string)value).Value;
                })
        });
    #endregion

    public static Regex expressionRestaraint = new Regex("[-a-zA-z0-9+*.\\(\\)\\[\\]\\{\\}]*");

    public string Text
    {
        get { (string)GetValue(TextProperty); }
        set 
        { 
            SetValue(TextProperty, value);
            tbxValue.Text = (string)GetValue(TextProperty);
        }
    }

    public bool IsEditingNumber
    {
        get 
        { 
            return (bool)GetValue(IsEditingNumberProperty); 
        }
        set 
        {
            bool old = (bool)GetValue(IsEditingNumberProperty);
            if (old != value)
            {
                if (!value)
                    stopEditing();
                else
                    startEditing();

                SetValue(IsEditingNumberProperty, value);
            }
        }
    } . . .

在主类中使用：

<Window x:Class="VisualMathExpression.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:edit="clr-namespace:VisualMathExpression.EditableTextBox"
    xmlns:all="clr-namespace:VisualMathExpression"
    Title="MainWindow" Height="350" Width="525">
<StackPanel>
    <edit:EditableTextBox HorizontalAlignment="Center" VerticalAlignment="Center"
                          Text="af" IsEditingNumber="True" /> . . .

---编辑--- 修复了包装（导致xaml属性在所有权属于声明的类时不会更改的问题）

    public partial class EditableTextBox : UserControl
{
    #region Dependency Properties
    public static readonly DependencyProperty IsEditingNumberProperty =
        DependencyProperty.Register("IsEditingNumber", typeof(bool), typeof(EditableTextBox),
        new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender) 
        { 
            PropertyChangedCallback = new PropertyChangedCallback((sender, arg) =>
                {
                    EditableTextBox ed = sender as EditableTextBox;
                    if (!(bool)arg.NewValue)
                        ed.stopEditing();
                    else
                        ed.startEditing();
                }),
        });

    public static readonly DependencyProperty TextProperty =
        DependencyProperty.Register("Text", typeof(string), typeof(EditableTextBox),
        new FrameworkPropertyMetadata("0", FrameworkPropertyMetadataOptions.AffectsRender) 
        { 
            PropertyChangedCallback = new PropertyChangedCallback((sender,arg) =>
                {
                    EditableTextBox ed = sender as EditableTextBox;
                    ed.tbxValue.Text = arg.NewValue as string;
                }),
            CoerceValueCallback = new CoerceValueCallback((sender,value) =>
                {
                    return expressionRestaraint.Match((string)value).Value;
                })
        });
    #endregion

    public static Regex expressionRestaraint = new Regex("[-a-zA-z0-9+*.\\(\\)\\[\\]\\{\\}]*");

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

    public bool IsEditingNumber
    {
        get { return (bool)GetValue(IsEditingNumberProperty); }
        set { SetValue(IsEditingNumberProperty, value); }
    }

Answer 1

DependencyProperty.Register方法的第三个参数ownerType必须是声明属性的类。

如果您的班级是MyClass，则声明必须如下所示：

public class MyClass : DependencyObject
{
    public static readonly DependencyProperty IsEditingNumberProperty =
        DependencyProperty.Register(
            "IsEditingNumber", typeof(bool), typeof(MyClass), ...);

    // CLR wrapper
    public bool IsEditingNumber
    {
        get { return (bool)GetValue(IsEditingNumberProperty); }
        set { SetValue(IsEditingNumberProperty, value); }
    }
}

属性已由'FrameworkElement'注册

1 个答案: