Image Binding，Silverlight，C＃，WP7(Image Binding, Silverlight, C#, WP7)

 我已经成功地将存储在独立存储中的图像绑定到XAML中定义的列表框内的“图像”元素，没有任何问题。 
 
 我所做的是使用一个属性来存储图像的名称和位置在隔离存储中，并使用IValueConverter来实际打开文件并获取其流。 
 
 我很惊讶地看到我不能在一个更简单的设置中使用新的XAML。 我只有这个： 
 
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <Grid.Resources>
            <c:BinaryToImageSRCConverter x:Key="imageConverter" />
        </Grid.Resources>
        <Image Name="TheImage" Source="{Binding PhotoName, Converter={StaticResource imageConverter}}" Width="430" Height="430" VerticalAlignment="Center" Stretch="UniformToFill">
        </Image>
    </Grid>
 
 这就是我在ModelView中所拥有的： 
 
        public string PhotoName { get; set; }
        PhotoName = "Images\\0.jpg";
 
 文件的路径和名称是正确的，因此它不是“找不到文件”的问题。 
 
 我的问题是我的IValueConverter的Convert方法永远不会被调用。 
 
 正如我之前提到的，我在另一个XAML（在同一个项目中）成功使用了这个转换器，一切正常。 唯一的区别是我绑定到ListBox使用的图像。 
 
 关于为什么我的IValueConverter的Convert方法在这种情况下没有被调用的任何想法或提示？ 
 
 谢谢！ 
 
 这是我尝试过的： 
 
 
 
 实现INotifyPropertyChanged ： 
public class PhotoNameClass : INotifyPropertyChanged
{
public string PhotoNameValue = string.Empty;

public event PropertyChangedEventHandler PropertyChanged;

private void NotifyPropertyChanged(String info)
{
    if (PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(info));
    }
}

public string PhotoName
{
    get
    {
        return this.PhotoNameValue;
    }
    set
    {
        if (value != this.PhotoNameValue)
        {
            this.PhotoNameValue = value;
            NotifyPropertyChanged("PhotoName");
        }
    }
}

}
 
 
 这就是我分配给该物业的方式： 
 
    public partial class ShowContent : PhoneApplicationPage
{
    PhotoNameClass photoClass = new PhotoNameClass();
}
   protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
    {
      photoClass.PhotoName = "Images\\0.jpg";
      base.OnNavigatedTo(e);
    }
 
 
 
 使用DependencyProperty 
public partial class ShowContent : PhoneApplicationPage
 {// PhotoNameClass photoClass = new PhotoNameClass（）; 
public string PhotoName
{
    get { return (string)GetValue(PhotoNameProperty); }
    set { SetValue(PhotoNameProperty, value); }
}

public static readonly DependencyProperty PhotoNameProperty = DependencyProperty.Register("PhotoName", typeof(string), typeof(ShowContent), new PropertyMetadata("")); 

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
   PhotoName = "Images\\0.jpg";
}
 
 
 以下是XAML的相关部分： 
 
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <Grid.Resources>
            <c:BinaryToImageSRCConverter x:Key="imageConverter" />
        </Grid.Resources>
        <Image Name="TheImage" Source="{Binding PhotoName, Converter={StaticResource imageConverter}}" Width="430" Height="430" VerticalAlignment="Center" Stretch="UniformToFill">
        </Image>
    </Grid>
 
 其中，c定义为： 
 
    xmlns:c="clr-namespace:ImageApplication"
 
 谢谢。 
 
 UPDATE 
 
 我正在使用INotifyPropertyChanged实现来公开我的属性。 
 
 我已将XAML代码更改为： 
 
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <Grid.Resources>
            <c:PhotoNameClass x:Key="photoClass" />
            <c:BinaryToImageSRCConverter x:Key="imageConverter" />
        </Grid.Resources>
            <Image Source="{Binding PhotoName, Converter={StaticResource imageConverter}}" DataContext="{StaticResource photoClass}" Width="430" Height="430" VerticalAlignment="Center" Stretch="UniformToFill">
            </Image>
    </Grid>
</Grid>
 
 因此，我添加了image元素的“DataContext”属性，指定包装我的属性的类的名称。 在这种情况下， 调用IValueConverter的Convert方法 。 但是，这是不正确的，因为我在添加DataContext时在XAML中收到错误：“无法确定调用者的应用程序身份”，当然，进入Convert方法时，我的“value”字符串为空，因此，“右侧“”PhotoName“未填充。 
 
 谢谢你的任何想法...... 
 
 PS这是我如何定义IValueConverter的Convert方法： 
 
namespace ImageApplication
{
  public class BinaryToImageSRCConverter : IValueConverter
  { 
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    { // <-- Breakpoint here. Never gets triggered except after I added the "DataContext" attribute to the XAML image element.
      // but in that case, "value" is an empty string.
        if (value != null && value is string)
        {
               ... 
 
 更新固定 
 
 我已经解决了这个问题。 我已将包含my property的类名分配给XAML代码中定义的映像的DataContext属性。 
 
 谢谢你们。 我希望这能帮助那里的人。 

I have successfully managed to bind images stored in Isolated Storage to "Image" elements inside a listbox defined in XAML w/o any problems.
 
What I did was to use a property that stored the name and location of the image in isolated storage and an IValueConverter to actually open the file and get its stream.
 
I am surprised to see that I can't do this in a new XAML with an even easier setup. All I have is this:
 
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <Grid.Resources>
            <c:BinaryToImageSRCConverter x:Key="imageConverter" />
        </Grid.Resources>
        <Image Name="TheImage" Source="{Binding PhotoName, Converter={StaticResource imageConverter}}" Width="430" Height="430" VerticalAlignment="Center" Stretch="UniformToFill">
        </Image>
    </Grid>
 
and this is what I have in the ModelView:
 
        public string PhotoName { get; set; }
        PhotoName = "Images\\0.jpg";
 
The path and name of the file is correct thus it is not a problem of "not finding the file".
 
My problem is that the Convert method of my IValueConverter never gets called. 
 
As I mentioned before, I am successfully using this converter in another XAML (in the same project) and everything works correctly. The only difference is that I am binding to an image used by a ListBox.
 
Any ideas or hints as to why the Convert method of my IValueConverter is not called in this scenario ?
 
Thanks!
 
Here is what I have tried:
 
 
 
Implementing INotifyPropertyChanged:
 
public class PhotoNameClass : INotifyPropertyChanged
{
public string PhotoNameValue = string.Empty;

public event PropertyChangedEventHandler PropertyChanged;

private void NotifyPropertyChanged(String info)
{
    if (PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(info));
    }
}

public string PhotoName
{
    get
    {
        return this.PhotoNameValue;
    }
    set
    {
        if (value != this.PhotoNameValue)
        {
            this.PhotoNameValue = value;
            NotifyPropertyChanged("PhotoName");
        }
    }
}

}
 
 
This is how I assigned to the property:
 
    public partial class ShowContent : PhoneApplicationPage
{
    PhotoNameClass photoClass = new PhotoNameClass();
}
   protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
    {
      photoClass.PhotoName = "Images\\0.jpg";
      base.OnNavigatedTo(e);
    }
 
 
 
Using DependencyProperty
 
public partial class ShowContent : PhoneApplicationPage
 
{ // PhotoNameClass photoClass = new PhotoNameClass();
 
public string PhotoName
{
    get { return (string)GetValue(PhotoNameProperty); }
    set { SetValue(PhotoNameProperty, value); }
}

public static readonly DependencyProperty PhotoNameProperty = DependencyProperty.Register("PhotoName", typeof(string), typeof(ShowContent), new PropertyMetadata("")); 

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
   PhotoName = "Images\\0.jpg";
}
 
 
Here are the relevant parts of the XAML:
 
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <Grid.Resources>
            <c:BinaryToImageSRCConverter x:Key="imageConverter" />
        </Grid.Resources>
        <Image Name="TheImage" Source="{Binding PhotoName, Converter={StaticResource imageConverter}}" Width="430" Height="430" VerticalAlignment="Center" Stretch="UniformToFill">
        </Image>
    </Grid>
 
where, c is defined as:
 
    xmlns:c="clr-namespace:ImageApplication"
 
Thanks.
 
UPDATE
 
I am using the INotifyPropertyChanged implementation to expose my property.
 
I have changed the XAML code to this:
 
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <Grid.Resources>
            <c:PhotoNameClass x:Key="photoClass" />
            <c:BinaryToImageSRCConverter x:Key="imageConverter" />
        </Grid.Resources>
            <Image Source="{Binding PhotoName, Converter={StaticResource imageConverter}}" DataContext="{StaticResource photoClass}" Width="430" Height="430" VerticalAlignment="Center" Stretch="UniformToFill">
            </Image>
    </Grid>
</Grid>
 
Therefore, I added the "DataContext" attribute of the image element specifying the name of the class that wraps my property. In this scenario, the Convert method of the IValueConverter IS called. However, this is not right as I am getting an error in the XAML when adding DataContext: "Unable to determine application identity of the caller" and of course, stepping into the Convert method, my "value" string is empty therefore, the "right" "PhotoName" is not being populated.
 
Thanks for any ideas...
 
P.S. Here's how I defined my Convert method of the IValueConverter:
 
namespace ImageApplication
{
  public class BinaryToImageSRCConverter : IValueConverter
  { 
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    { // <-- Breakpoint here. Never gets triggered except after I added the "DataContext" attribute to the XAML image element.
      // but in that case, "value" is an empty string.
        if (value != null && value is string)
        {
               ... 
 
UPDATE FIXED
 
I have fixed the issue. I have assigned the class name wrapping my property to the DataContext property of the image defined in the XAML code.
 
Thank you all. I hope this will help somebody out there.

原文：https://stackoverflow.com/questions/7973473