wpf 图像源绑定到本地存储中的文件
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Image Source binding to file in local Storage
提问by max06
In Windows Metro Apps (C#), I'm using a ValueConverter to pass an Image-Uri like this:
在 Windows Metro 应用程序 (C#) 中，我使用 ValueConverter 来传递这样的 Image-Uri：
public class ProfileImage : IValueConverter {
public Object Convert(Object value, Type targetType, Object parameter, String language) {
if (value == null) {
return "Common/images_profile/user.png";
}
return "ms-appdata:///local/" + (String)value;
}
public Object ConvertBack(Object value, Type targetType, Object parameter, String language) {
return value;
}
}
XAML:
XAML：
<Image x:Name="profileImage" Height="80" Width="80" Source="{Binding Path, Converter={StaticResource ProfileImage}}"/>
The images are being downloaded async into localFolder.
图像被异步下载到 localFolder 中。
I wanted to use this on Windows Phone 8 - but it doesn't show up any image.
我想在 Windows Phone 8 上使用它 - 但它没有显示任何图像。
var localFolder = ApplicationData.Current.LocalFolder;
StorageFile myFile = await localFolder.CreateFileAsync(
UID + ".jpg",
CreationCollisionOption.FailIfExists);
using (var s = await myFile.OpenStreamForWriteAsync()) {
s.Write(imageBytes, 0, imageBytes.Length);
}
is used for writing the Images to the LocalStorage.
用于将图像写入 LocalStorage。
If there's no content in value, the Image in Common/images_profile/user.pngis being displayed properly. This one is in the package, not in the local Folder.
如果 中没有内容value，则图像中Common/images_profile/user.png的显示正确。这是在包中，而不是在本地文件夹中。
I need to know which format I have to use as return parameter to get the images displayed.
我需要知道必须使用哪种格式作为返回参数才能显示图像。
采纳答案by chrs.zrkl
I think the URL scheme ms-appdata:///does not work everywhere.
我认为 URL 方案ms-appdata:///并不适用于任何地方。
I'm using this conveter for binding images from isolated storage:
我正在使用这个转换器来绑定来自独立存储的图像：
public class PathToImageConverter : IValueConverter
{
private static IsolatedStorageFile isoStorage = IsolatedStorageFile.GetUserStoreForApplication();
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string path = value as string;
if (string.IsNullOrEmpty(path))
return null;
if ((path.Length > 9) && (path.ToLower().Substring(0, 9).Equals("isostore:")))
{
using (var sourceFile = isoStorage.OpenFile(path.Substring(9), FileMode.Open, FileAccess.Read))
{
BitmapImage image = new BitmapImage();
image.SetSource(sourceFile);
return image;
}
}
else
{
BitmapImage image = new BitmapImage(new Uri(path));
return image;
}
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
For binding, you must use the isostore:prefix in your url.
对于绑定，您必须在 url 中使用isostore:前缀。
回答by Hermit Dave
must be missing something here.. why don't you use StorageFile.Path instead of returning "return "ms-appdata:///local/" + (String)value;"
一定在这里遗漏了一些东西..为什么不使用 StorageFile.Path 而不是返回“返回“ms-appdata:///local/”+（字符串）值；“
Realised that its #WP8 so another thing. You can still use isolated storage and Silverlight Uri
意识到它的#WP8 是另一回事。您仍然可以使用独立存储和 Silverlight Uri
