在VB.NET轉換JPEG至PNG（保存的輸出沒有擴展名）

Question

這是我在我的轉換圖像代碼

Public Sub ConvertImage(ByVal Filename As String, _ 
     ByVal DesiredFormat As System.Drawing.Imaging.ImageFormat, _ 
     ByVal NewFilename As String) 
     NewFilename = "ConvertedToPNG-" + NewFilename + "-" + Format(Date.Now, "MMMMddyyyyhhmmtt") 
     Try 
      Dim imgFile As System.Drawing.Image = _ 
       System.Drawing.Image.FromFile(Filename) 
      imgFile.Save(txtPNGFileDestination.Text & "\" & NewFilename, DesiredFormat) 
     Catch ex As Exception 
      Throw ex 
     End Try 
    End Sub 

它正常運行，但保存的圖像已經沒有PNG文件擴展名由此只是一個文件。我做錯了什麼？

感謝您的幫助

Answer 1

只需將擴展名添加到NewFileName。您還需要申報NewFileName「的ByRef」：

Public Sub ConvertImage(ByVal Filename As String, ByVal DesiredFormat As System.Drawing.Imaging.ImageFormat, ByRef NewFilename As String) 
    NewFilename = "ConvertedToPNG-" + NewFilename + "-" + Format(Date.Now, "MMMMddyyyyhhmmtt") & "." & DesiredFormat.ToString