how to set progress bar during copying file from o

问题:

Currently I'm doing project in vb.net and I want to set the progress bar while copying files from one folder to another. And the progress bar should move towards completion according to amount of file copied.

回答1:

Concept used: Get the count of files in the source directory, and then whenever copying a file from source folder to destination folder increment a variable to trace how many files get transferred. Now calculate the files transferred percentage by using the following formula,

% of files transferred = How many files Transferred * 100 / Total No of files in source folder

And then after getting the % of files transferred, update the progress bar's value by using it.

Try this code : Tested with IDE

  Dim xNewLocataion = "E:\Test1"

        Dim xFilesCount = Directory.GetFiles("E:\Test").Length
        Dim xFilesTransferred As Integer = 0

        For Each xFiles In Directory.GetFiles("E:\Test")

            File.Copy(xFiles, xNewLocataion & "\" & Path.GetFileName(xFiles), True)
            xFilesTransferred += 1

            ProgressBar1.Value = xFilesTransferred * 100 / xFilesCount
            ProgressBar1.Update()

        Next

回答2:

Not so new question, but here's an answer nonetheless. The following code will achieve the desired result whereby an individual file's progress is tracked. It uses a 1 MiB buffer. Depending on your system's resources, you can adjust the buffer accordingly to tweak the performance of the transfer.

Concept: Count each byte as it is read/written and report the progress based on the total size of the source file, using file streams.

'Create the file stream for the source file
Dim streamRead as New System.IO.FileStream([sourceFile], System.IO.FileMode.Open)
'Create the file stream for the destination file
Dim streamWrite as New System.IO.FileStream([targetFile], System.IO.FileMode.Create)
'Determine the size in bytes of the source file (-1 as our position starts at 0)
Dim lngLen as Long = streamRead.Length - 1
Dim byteBuffer(1048576) as Byte   'our stream buffer
Dim intBytesRead as Integer    'number of bytes read

While streamRead.Position < lngLen    'keep streaming until EOF
    'Read from the Source
    intBytesRead = (streamRead.Read(byteBuffer, 0, 1048576))
    'Write to the Target
    streamWrite.Write(byteBuffer, 0, intBytesRead)
    'Display the progress
    ProgressBar1.Value = CInt(streamRead.Position / lngLen * 100)
    Application.DoEvents()    'do it
End While

'Clean up 
streamWrite.Flush()
streamWrite.Close()
streamRead.Close()