相关疑难解决方法(0)

我需要为上传的图像添加元数据标签(描述).

我找到了这个答案:https://stackoverflow.com/a/1764913/6776适用于JPG文件,但不适用于PNG.

private string Tag = "test meta data";

private static Stream TagImage(Stream input, string type)
{
    bool isJpg = type.EndsWith("jpg", StringComparison.InvariantCultureIgnoreCase) || type.EndsWith("jpeg", StringComparison.InvariantCultureIgnoreCase);
    bool isPng = type.EndsWith("png", StringComparison.InvariantCultureIgnoreCase);

    BitmapDecoder decoder = null;

    if (isJpg)
    {
        decoder = new JpegBitmapDecoder(input, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
    }
    else if (isPng)
    {
        decoder = new PngBitmapDecoder(input, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
    }
    else
    {
        return input;
    }

    // modify the metadata
    BitmapFrame bitmapFrame = decoder.Frames[0];
    BitmapMetadata metaData = (BitmapMetadata)bitmapFrame.Metadata.Clone();
    metaData.Subject = Tag;
    metaData.Comment …