保存位图图像列表
保存位图图像列表
提问于 2017-02-17 05:16:48
我有一个位图图像列表。我需要将它们保存到本地文件夹。这在Windows10通用应用程序上不起作用。
var serializer = new DataContractSerializer(typeof(List<BitmapImage>));
using (var stream = await ApplicationData.Current.LocalCacheFolder.OpenStreamForWriteAsync(fileName, CreationCollisionOption.ReplaceExisting)) {
serializer.WriteObject(stream, collection);
}WriteObject方法引发以下错误
Exception thrown: 'System.Runtime.Serialization.InvalidDataContractException' in System.Private.DataContractSerialization.dll回答 2
Stack Overflow用户
发布于 2017-02-17 05:33:49
BitmapImage不可序列化。将其转换为字节数组，并将其写入磁盘：
public static byte[] ConvertToBytes(BitmapImage bitmapImage)
{
using (var ms = new MemoryStream())
{
var btmMap = new WriteableBitmap(bitmapImage.PixelWidth, bitmapImage.PixelHeight);
btmMap.SaveJpeg(ms, bitmapImage.PixelWidth, bitmapImage.PixelHeight, 0, 100);
return ms.ToArray();
}
}
var serializer = new DataContractSerializer(typeof(byte[]));
using (var stream = await ApplicationData.Current.LocalCacheFolder.OpenStreamForWriteAsync(fileName, CreationCollisionOption.ReplaceExisting)) {
serializer.WriteObject(stream, ConvertToBytes(collection));
}Stack Overflow用户
发布于 2017-03-01 10:21:11
不能从BitmapImage中提取位图。没有办法直接将BitmapImage保存到文件中。唯一的办法就是记住原始源，然后保存下来。有关将BitmapImage保存到文件的更多详细信息，请参考this thread。
如果您知道原始源，例如，您从FileOpenPicker拾取的文件中读取BitmapImage，那么您可以将图像文件读取到WriteableBitmap，然后您可以提取PixelBuffer，使用BitmapEncoder对其进行编码，然后像Rob所说的那样将结果流保存到StorageFile。示例代码如下：
private async void btncreate_Click(object sender, RoutedEventArgs e)
{
FileOpenPicker openpicker = new FileOpenPicker();
openpicker.FileTypeFilter.Add(".jpg");
openpicker.FileTypeFilter.Add(".png");
StorageFile originalimage = await openpicker.PickSingleFileAsync();
WriteableBitmap writeableimage1;
using (IRandomAccessStream stream = await originalimage.OpenAsync(FileAccessMode.Read))
{
SoftwareBitmap softwareBitmap;
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(stream);
softwareBitmap = await decoder.GetSoftwareBitmapAsync();
writeableimage1 = new WriteableBitmap(softwareBitmap.PixelWidth, softwareBitmap.PixelHeight);
writeableimage1.SetSource(stream);
}
StorageFolder folder = ApplicationData.Current.LocalFolder;
StorageFile newimage = await folder.CreateFileAsync(originalimage.Name, CreationCollisionOption.ReplaceExisting);
using (IRandomAccessStream ras = await newimage.OpenAsync(FileAccessMode.ReadWrite))
{
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, ras);
var stream = writeableimage1.PixelBuffer.AsStream();
byte[] buffer = new byte[stream.Length];
await stream.ReadAsync(buffer, 0, buffer.Length);
encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore, (uint)writeableimage1.PixelWidth, (uint)writeableimage1.PixelHeight, 96.0, 96.0, buffer);
await encoder.FlushAsync();
}
}对于镜像列表，您可能需要逐个保存。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/42284802
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