'這邊我舉一個簡單的讀取emf檔案作為例子，實際應用是其它的metafile
Dim metafile As New Metafile("D:\12345.emf")
我用下面這行代碼保存出來的emf檔案無法加載到visio中，提示“匯入圖形檔案失敗”，不得以棄用
metafile.Save("D:\\11111.emf", ImageFormat.Emf)
改用下面函式后（SaveEnhMetafileToFile）保存的檔案可以被visio加載，并“曲線組合”，這是我需要的，
'但問題在于必須關閉exe后才能洗掉檔案， 檔案一直被占用著，求大神幫忙看看問題在哪里？
Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices
Imports System.Text
<DllImport("user32.dll")>
Private Shared Function OpenClipboard(hWndNewOwner As IntPtr) As Boolean
End Function
<DllImport("user32.dll")>
Private Shared Function EmptyClipboard() As Boolean
End Function
<DllImport("user32.dll")>
Private Shared Function SetClipboardData(uFormat As UInteger, hMem As IntPtr) As IntPtr
End Function
<DllImport("user32.dll")>
Private Shared Function CloseClipboard() As Boolean
End Function
<DllImport("gdi32.dll")>
Private Shared Function CopyEnhMetaFile(hemfSrc As IntPtr, hNULL As System.Text.StringBuilder) As IntPtr
End Function
<DllImport("gdi32.dll")>
Private Shared Function CloseEnhMetaFile(hdc As IntPtr) As Integer
End Function
<DllImport("gdi32.dll")>
Private Shared Function DeleteEnhMetaFile(hemf As IntPtr) As IntPtr
End Function
Public Function SaveEnhMetafileToFile(mf As Metafile, fileName As String) As Boolean
Dim bResult As Boolean = False
Dim hEMF As IntPtr
Try
hEMF = mf.GetHenhmetafile()
If Not hEMF.Equals(New IntPtr(0)) Then
Dim tempName As New StringBuilder(fileName)
CopyEnhMetaFile(hEMF, tempName)
CloseEnhMetaFile(hEMF) '=====沒用，，還是被占用
DeleteEnhMetaFile(hEMF) '=====還是沒用，，還是被占用
mf.Dispose() '=====依然沒用，，還是被占用，崩潰了
End If
Catch ex As Exception
Return False
End Try
Return bResult
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'這邊我舉一個簡單的讀取emf檔案作為例子，實際應用是其它的metafile
Dim metafile As New Metafile("D:\12345.emf")
'我用下面這行代碼保存出來的emf檔案無法加載到visio中，提示“匯入圖形檔案失敗”，不得以棄用
'metafile.Save("D:\\11111.emf", ImageFormat.Emf)
'改用下面函式后保存的檔案可以被visio加載，并“曲線組合”，這是我需要的，
'但問題在于必須關閉exe后才能洗掉檔案， 檔案一直被占用著
SaveEnhMetafileToFile(metafile, "D:\\22222.emf")
End Sub
uj5u.com熱心網友回復：
找到原因了，需要洗掉CopyEnhMetaFile創建的句柄，Friend Shared Function SaveEnhMetafileToFile(mf As Metafile, fileName As String) As Boolean
Dim bResult As Boolean = False
Dim hEMF As IntPtr
hEMF = mf.GetHenhmetafile()
' invalidates mf
If Not hEMF.Equals(New IntPtr(0)) Then
Dim tempName As New StringBuilder(fileName)
Dim hCopyEMF As IntPtr = CopyEnhMetaFile(hEMF, tempName.ToString())
DeleteEnhMetaFile(hCopyEMF)
DeleteEnhMetaFile(hEMF)
End If
Return bResult
End Function
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/207441.html
標籤：VB.NET
上一篇：下拉提示
下一篇：linq請教