只能在 DependencyObject 的 DependencyProperty 上设置“绑定" [英] A 'Binding' can only be set on a DependencyProperty of a DependencyObject

问题描述

从一个基于TextBox的自定义控件，我创建了一个名为Items的属性，这样:

From a custom control based on TextBox, I created a property named Items, in this way:

public class NewTextBox : TextBox
{
    public ItemCollection Items { get; set; }
}

在 XAML 中使用自定义控件时，我无法绑定属性，因为它引发异常只能在 DependencyObject 的 DependencyProperty 上设置绑定".

When using the custom control in XAML, I cannot bind the property because it raises exception "A 'Binding' can only be set on a DependencyProperty of a DependencyObject.".

如何解决这个异常?

推荐答案

作为旁注，另外值得注意的是，如果您在对象之间进行复制和粘贴而忘记更改第二个 ，则会出现这些绑定错误typeof(Object) 语句.

As a side note, it is also worth noting that you will get these binding errors if you copy and paste between objects and forget to change the second typeof(Object) statement.

我一小时想不通为什么会出现此错误，因为一切似乎都已定义且正确.我已经将我的属性移动到用户控件中，因为我想从单个集合转到一个列表.因此:

I couldn't figure out for a good hour why I was getting this error as everything appeared to be defined and correct. I'd moved my properties into a usercontrol as I wanted to go from a single set to a list. Thus:

public static readonly DependencyProperty FoldersProperty = DependencyProperty
    .Register("Folders", typeof(OutlookFolders), typeof(MainWindow),
    new FrameworkPropertyMetadata(new OutlookFolders()));

public OutlookFolders Folders
{
    get { return GetValue(FoldersProperty) as OutlookFolders; }
    set { SetValue(FoldersProperty, value); }
}

应该变成:

public static readonly DependencyProperty FoldersProperty = DependencyProperty
    .Register("Folders", typeof(OutlookFolders), typeof(SavedFolderControl), 
    new FrameworkPropertyMetadata(new OutlookFolders()));

public OutlookFolders Folders
{
    get { return GetValue(FoldersProperty) as OutlookFolders; }
    set { SetValue(FoldersProperty, value); }
}

在我进行此更改之前，我一直收到错误消息:无法在SavedFolderControl"类型的属性文件夹"上设置绑定".只能在 DependencyObject 的 DependencyProperty 上设置绑定".

Until I did this change I kept receiving the error: A 'Binding' cannot be set on the property 'Folders' of type 'SavedFolderControl'. A 'Binding' can only be set on a DependencyProperty of a DependencyObject.

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