WP7 Isolated Storage详解-读取、保存图片文件（转载）

转载自： http://www.zdave.net/archives/369：

保存图片到隔离存储空间

示例中首先检查文件是否已经存在，然后把图片保存到隔离存储空间（转换WriteableBitmap对象到JPEG stream）。

String tempJPEG = "logo.jpg";

 

using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())

{

    if (myIsolatedStorage.FileExists(tempJPEG))

    {

        myIsolatedStorage.DeleteFile(tempJPEG);

    }

 

    IsolatedStorageFileStream fileStream = myIsolatedStorage.CreateFile(tempJPEG);

 

    StreamResourceInfo sri = null;

    Uri uri = new Uri(tempJPEG, UriKind.Relative);

    sri = Application.GetResourceStream(uri);

 

    BitmapImage bitmap = new BitmapImage();

    bitmap.SetSource(sri.Stream);

    WriteableBitmap wb = new WriteableBitmap(bitmap);

 

    // Encode WriteableBitmap object to a JPEG stream.

    Extensions.SaveJpeg(wb, fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85);

 

    fileStream.Close();

}

 

提示：你也可以使用WriteableBitmap来保存图片：wb.SaveJpeg(fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85);

从隔离存储空间读取图片

示例中首先从隔离存储空间打开了一个名为logo.jpg的图片，并在一个Image控件中呈现出来。

 

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BitmapImage bi = new BitmapImage();                using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())             {                 using (IsolatedStorageFileStream fileStream = myIsolatedStorage.OpenFile("logo.jpg", FileMode.Open, FileAccess.Read))                 {                     bi.SetSource(fileStream);                     this.img.Height = bi.PixelHeight;                     this.img.Width = bi.PixelWidth;                 }             }             this.img.Source = bi;

提示：“img”是一个在MainPage.xaml中的图片控件：<Image x:Name="img"/>

保存图片到手机媒体库

访问MediaLibrary需要在项目中添加引用：Microsoft.XNA.Framework。

示例中从隔离存储空间中读取一个图片，然后保存到手机的媒体库中。

 

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using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())             {                 using (IsolatedStorageFileStream fileStream = myIsolatedStorage.OpenFile("logo.jpg", FileMode.Open, FileAccess.Read))                 {                     MediaLibrary mediaLibrary = new MediaLibrary();                     Picture pic = mediaLibrary.SavePicture("SavedLogo.jpg", fileStream);                     fileStream.Close();                 }             }                PhotoChooserTask photoChooserTask = new PhotoChooserTask();             photoChooserTask.Show();