[TemplatePart(Name = informationBubble.informationBubbleTitlePart,Type = typeof(TextBlock))]
[TemplatePart(Name = informationBubble.informationBubbleProductimagePart,Type=typeof(Image))]

public class informationBubble : Control 
{
    #region Template Parts Name Constants

    /// <summary>
    /// Name constant for the information Bubble Title Part
    /// </summary>
    public const string informationBubbleTitlePart = "informationBubbleTitleText";

    /// <summary>
    /// Name constant for the information Bubble Product Image Part
    /// </summary>
    public const string informationBubbleProductimagePart = "informationBubbleProductimage";

    #endregion

    #region TemplateParts

    private TextBlock _Title;

    internal TextBlock Title
    {
        get { return _Title; }
        private set
        {
            _Title = value;

            if (_Title != null)
            {
                _Title.Text = this.ProductTitleText;       
            }
        }
    }

    private Image _Productimage;

    internal Image Productimage
    {
        get { return _Productimage; }
        private set
        {
            _Productimage = value;

            if (_Productimage != null)
            {
                _Productimage.source = this.ProductimageSource;
            }
        }
    }

    #endregion

    #region Public String Product Title 

    // Dependency properties declaration
    public static readonly DependencyProperty ProductTitleProperty = DependencyProperty.Register(
        "ProductTitle",typeof(string),typeof(informationBubble),new PropertyMetadata(string.Empty,new PropertyChangedCallback(OnProductTitleChanged)));

    public static void OnProductTitleChanged(DependencyObject sender,DependencyPropertyChangedEventArgs e)
    {
        informationBubble iBubble = sender as informationBubble;

        if (iBubble.Title != null)
        {
            iBubble.Title.Text = e.NewValue as string;
        }
    }

    public string ProductTitleText
    {
        get { return GetValue(ProductTitleProperty) as string; }
        set { SetValue(ProductTitleProperty,value); }
    }

    #endregion

    #region Public Image Source Product Image

    public static readonly DependencyProperty ProductimageSourceProperty = DependencyProperty.Register(
        "ProductimageSource",typeof(ImageSource),new PropertyMetadata(null,new PropertyChangedCallback(OnProductimageSourceChanged)));

    public static void OnProductimageSourceChanged(DependencyObject sender,DependencyPropertyChangedEventArgs e)
    {
        informationBubble iBubble = sender as informationBubble;

        if (iBubble.Productimage != null)
        {
            iBubble.Productimage.source = e.NewValue as ImageSource;
        }
    }

    public ImageSource ProductimageSource
    {
        get { return GetValue(ProductimageSourceProperty) as ImageSource; }
        set { SetValue(ProductimageSourceProperty,value); }
    }

    #endregion

    public informationBubble()
    {
         this.DefaultStyleKey = typeof(informationBubble);
    }

    #region Overrides

    public override void OnApplyTemplate()
    {       
        base.OnApplyTemplate();

        Title = GetTemplateChild(informationBubble.informationBubbleTitlePart) as TextBlock;
        Productimage = GetTemplateChild(informationBubble.informationBubbleProductimagePart) as Image;
    }

    #endregion

    #region Private Methods

    private void GoToState(string stateName,bool useTransitions)
    {
        visualstatemanager.GoToState(this,stateName,useTransitions);
    }

    #endregion
}

现在,如果我在我的xaml中的某个地方使用此控件,那么如果我执行此操作：

<controls:informationBubble 
        ProductimageSource="{Binding SelectedItem.normalImageSource}"
        ProductTitleText="Test Title"
        "/>

但是,如果我尝试将数据绑定到viewmodel中的SelectedItem对象的title属性的数据：

<controls:informationBubble 
            ProductimageSource="{Binding SelectedItem.normalImageSource}"
            ProductTitleText="{Binding SelectedItem.Title,Mode=TwoWay"
            "/>

我得到’System.Windows.Data.Binding’类型的对象不能转换为’System.String’类型. TextBlock的text属性是DependencyProperty,所​​以我必须在这里遗漏一些明显的东西.

非常感谢任何帮助或见解.

短剑的一种

public static readonly DependencyProperty ProductTitleProperty = DependencyProperty.Register(
    "ProductTitle",// "ProductTitleText" ?
    typeof(string),new PropertyChangedCallback(OnProductTitleChanged)));

我想当你使用字符串常量时,WPF使用反射直接访问属性“public string ProductTitleText”. DependencyProperty被忽略,因为属性的名称不匹配(“ProductTitle”与“ProductTitleText”).

因此,对于标题,您有一个名为“ProductTitle”的依赖项属性和一个名为“ProductTitleText”的(字符串)属性.
对于Productimage,您有一个名为“ProductimageSource”的依赖项proeprty和一个名为“ProductimageSource”的属性(ImageSource类型).

是否有意义？