c# - 创建图像的缩略图并将它们存储在缓存中

Question

我有一个 WPF 应用程序，它有一个图像列表框。现在我正在使用 BitmapImage和 BitmapCacheOption.OnLoad加载图像。

问题是当有很多图像时，由于图像的大小，RAM 使用率飙升。

如何创建要在列表框中显示的原件的缩略图？

它可能必须被缓存，因为目录中的图像文件可能在应用程序运行时被删除或修改。

Answer 1

The problem is that when there are a lot of images, the RAM usage sky rockets due to the size of the images.

C# 示例来自:http://msdn.microsoft.com/en-us/library/ms748873.aspx

// Create source
BitmapImage myBitmapImage = new BitmapImage();

// BitmapImage.UriSource must be in a BeginInit/EndInit block
myBitmapImage.BeginInit();
myBitmapImage.UriSource = new Uri(@"C:\Water Lilies.jpg");

// To save significant application memory, set the DecodePixelWidth or  
// DecodePixelHeight of the BitmapImage value of the image source to the desired 
// height or width of the rendered image. If you don't do this, the application will 
// cache the image as though it were rendered as its normal size rather then just 
// the size that is displayed.
// Note: In order to preserve aspect ratio, set DecodePixelWidth
// or DecodePixelHeight but not both.
myBitmapImage.DecodePixelWidth = 200;
myBitmapImage.EndInit();
//
//when you are ready to render the BitmapImage, do:
imageThumb.Source = myBitmapImage;

请注意 DecodePixelWidth 和 DecodePixelHeight 属性，以按所需的缩小像素大小缓存图像。使用两者来拉伸(stretch)图像以适合缩略图大小。