ファイルを少しずつコピーしたい (必要に応じてコピー操作をキャンセルするため)。
私はここでマークされていない解決策に従おうとしています:コピーをキャンセルする機能でファイルをコピーする方法は?
しかし、私は0バイトのファイルを取得しています
私が間違っていることは何ですか？
Public Class Form1
Dim cancelled As Boolean = Nothing
Dim input = New System.IO.FileStream("C:\1.txt", System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read)
Dim output = New System.IO.FileStream("C:\Nueva carpeta\1.txt", System.IO.FileMode.CreateNew, System.IO.FileAccess.Write, System.IO.FileShare.Write)
Public Sub CopyStream(ByVal inputStream As System.IO.Stream, ByVal outputStream As System.IO.Stream)
'Dim buffer = System.IO.File.ReadAllBytes("C:\1.txt")
Dim buffer = New Byte((1024) - 1) {}
Dim bytesRead As Integer = 1
While (inputStream.Read(buffer, 0, buffer.Length) > 0)
outputStream.Write(buffer, 0, bytesRead)
'bytesRead += 1
If cancelled Then
MsgBox("operacion cancelada")
Return
End If
End While
inputStream.Close()
outputStream.Close()
MsgBox("operacion terminada")
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
CopyStream(input, output)
End Sub
End Class
**
更新 1:
**
Virtlink の回答の手順に従い、不足している部分を元のコードに入れようとしましたが、まだゼロバイトのファイルを取得しています。
> Public Class Form1
Dim input = New System.IO.FileStream("C:\Test.txt", System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read)
Dim output = New System.IO.FileStream("C:\Test_New.txt", System.IO.FileMode.CreateNew, System.IO.FileAccess.Write, System.IO.FileShare.Write)
Public Sub CopyStream(ByVal inputStream As System.IO.Stream, ByVal outputStream As System.IO.Stream)
Dim buffer = New Byte(1024) {}
Dim bytesRead As Integer
' Read some bytes
While (bytesRead = inputStream.Read(buffer, 0, buffer.Length) > 0)
' Write them to the output
outputStream.Write(buffer, 0, bytesRead)
End While
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
CopyStream(input, output)
End Sub
End Class
**
更新 2:
**
私の最近の失敗した試み：
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim input_filepath As String = "C:\Test.txt", output_filepath As String = "C:\Test_New.txt"
Dim input = New System.IO.FileStream(input_filepath, System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite)
Dim output = New System.IO.FileStream(output_filepath, System.IO.FileMode.Create, System.IO.FileAccess.ReadWrite)
CopyStream(input, output)
' For Testing:
If New IO.FileInfo(output_filepath).Length = 0 Then IO.File.Delete(output_filepath) : Application.Exit() Else Process.Start("Notepad", output_filepath)
End Sub
Public Sub CopyStream(ByVal inputStream As System.IO.Stream, ByVal outputStream As System.IO.Stream)
Dim buffer = New Byte(1024) {}, bytesRead As Integer
While ((bytesRead = inputStream.Read(buffer, 0, buffer.Length)) > 0)
outputStream.Write(buffer, 0, bytesRead)
End While
inputStream.Flush() : outputStream.Flush()
inputStream.Close() : outputStream.Close()
End Sub
End Class
**
更新 3:
**
解決
問題はVB.NETにあり、ループ条件で変数に値を割り当てることができないため、これが機能するサブです:
Public Sub CopyStream(ByVal inputStream As Stream, ByVal outputStream As Stream)
Dim buffer = New Byte(1025) {}
Dim bytesRead As Integer = 0
Do
bytesRead = inputStream.Read(buffer, 0, buffer.Length)
If bytesRead > 0 Then
outputStream.Write(buffer, 0, bytesRead)
End If
Loop While (bytesRead > 0)
outputStream.Flush()
inputStream.Close() : outputStream.Close()
End Sub