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[英]Using Impersonation for VB.NET WinForm Application, Can Save File, Can't Open File
[英]Using the open file and save file dialogs in vb.net
用戶通過“打開文件”對話框選擇文件后,如何處理此操作? 例如,如果用戶選擇了一個.txt文件並打開了該文件,那么如何從該文件中獲取數據? 如何返回用戶在其中找到文件的路徑? 那么,如何保存文件?
我知道有一個OpenFileDialog.OpenFile()方法,但是我也很確定這不是我想要的。 我也嘗試了ToObject方法,但是我可能以某種方式弄亂了。
例如,是否有快速簡便的方法來打開圖像?
謝謝您的幫助!
順便說一下,這是在VB.net中。
Dim dlg_open As New OpenFileDialog()
If (dlg_open.Show() <> DialogResult.OK) Then Return
'if a textfile, then
Dim content As String() = IO.File.ReadAllLines(dlg_open.FileName)
'if an image, then
Dim img As New Bitmap(dlg_open.FileName)
您應該在處理IO的所有操作周圍放置Try ... Catch塊,否則將無法防止所有異常。
這是一個很好的示例: https : //web.archive.org/web/1/http : //blogs.techrepublic%2ecom%2ecom/programming-and-development/?p=481 。
這是一個瑣碎的問題,谷歌可以在幾秒鍾內回答。
您要處理FileOk事件:
Private Sub OpenFileDialog1_FileOk(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles OpenFileDialog1.FileOk
Dim path As String = OpenFileDialog1.FileName
If fileIsBitmap Then
' say the file is a bitmap image '
Dim bmp As New Bitmap(path)
' rotate the image 90 degrees '
bmp.RotateFlip(RotateFlipType.Rotate90FlipNone)
' save the image '
bmp.Save(path)
ElseIf fileIsTextFile Then
' or say the file is a text file '
Dim fs As New IO.FileStream(path, IO.FileMode.Append)
Dim sr As New IO.StreamWriter(fs)
' write a new line at the end of the file '
sr.WriteLine("This is a new line.")
' close the FileStream (this saves the file) '
sr.Close()
fs.Close()
End If
End Sub
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