Vb.net 在picturebox中显示Jpeg的元数据缩略图

我需要显示图像的缩略图，它保存在picturebox的元数据中。我正在使用VB.NET

到目前为止，我想出了这个。添加断点会显示GETQUERY返回空，即使我知道文件确实有缩略图

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Dim imagepath = "C:\xampp\htdocs\Downloads\IMG_1322.JPG" ' path to file
    Dim stream = New FileStream(imagepath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)
    Dim decoder = New JpegBitmapDecoder(stream, BitmapCreateOptions.None, BitmapCacheOption.None)
    Dim metadata = TryCast(decoder.Frames(0).Metadata, BitmapMetadata)

    Dim ms As New System.IO.MemoryStream

    Dim bm As Bitmap
    Dim arData() As Byte

    arData = metadata.GetQuery("/app0/{ushort=6}") '<--- Breakpoint here: Query returns nothing!


    ms.Write(arData, 78, arData.Length - 78)

    bm = New Bitmap(ms)

    PictureBox1.Image = bm
    stream.Close()

End Sub

Private Sub Form1\u Load（发送方作为System.Object，e作为System.EventArgs）处理MyBase.Load
Dim imagepath=“C:\xampp\htdocs\Downloads\IMG_1322.JPG”文件路径
Dim stream=新文件流（imagepath、FileMode.Open、FileAccess.Read、FileShare.ReadWrite）
Dim decoder=新的JpegBitmapDecoder（流，BitmapCreateOptions.None，BitmapCacheOption.None）
Dim metadata=TryCast（解码器。帧（0）。元数据，位图元数据）
将ms变暗为新System.IO.MemoryStream
将bm设置为位图
Dim arData（）作为字节
arData=metadata.GetQuery（“/app0/{ushort=6}”）您可以尝试以下方法：

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Dim imagepath = "C:\xampp\htdocs\Downloads\IMG_1322.JPG" ' path to file
    Dim stream = New FileStream(imagepath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)
    Dim decoder = New JpegBitmapDecoder(stream, BitmapCreateOptions.None, BitmapCacheOption.None)
    Dim metadata = TryCast(decoder.Frames(0).Metadata, BitmapMetadata)

    Dim thumb As BitmapMetadataBlob
    thumb = metadata.GetQuery("/app1/thumb/")
    If Not (thumb Is Nothing) Then
        Dim src As New BitmapImage
        Dim ms As MemoryStream = New MemoryStream(thumb.GetBlobValue())
        src.BeginInit()
        src.StreamSource = ms
        src.EndInit()
        PictureBox1.Source = src
    End If
    stream.Close()

End Sub

耶！你是最棒的你的代码中有一个类型。bm未声明，ms声明2次。但它太棒了！谢谢您如何找到IPTC数据的查询路径？例如，如何知道要编写什么查询来获取/设置图像的标题？