将 WIA 项属性"Thumbnail Data"转换为 .NET 图像

Question

如何将Wia缩略图转换为.net图像？如果我加载属性，我会得到一个Com对象，但我现在不知道如何处理它。

Answer 1

WIAitem Thumbnail属性是wia.vector对象，属性二进制数据可以很容易地转换为带有image.fromstream的.net图像。以下是代码：

Public Shared Function GetThumbnail(Item As WIA.Item) As Image
Dim Jpeg As WIA.ImageFile = Nothing
With Item
  If .Properties.Exists("Thumbnail Data") Then
    Dim Thumb As WIA.Vector
    Thumb = .Properties("Thumbnail Data").Value
    Jpeg = Thumb.ImageFile(CInt(.Properties("Thumbnail Width").Value), CInt(.Properties("Thumbnail Height").Value))
  End If
End With
If Jpeg IsNot Nothing Then
  Dim imageBytes As Byte() = Jpeg.FileData.BinaryData
  Using ms As New IO.MemoryStream(imageBytes)
    Dim img As Image = Image.FromStream(ms)
    ms.Close()
    Return img
  End Using
Else
  Return Nothing
End If
End Function