每个循环的process.start问题 [英] process.start problem in for each loop

问题描述

在通过按钮单击代码调用命令行应用程序时，我陷入了困境.

该应用程序为ffmpeg.
我的应用程序是将pdf文档转换为图像到电影文件.
我首先创建一个用于复制图像的临时目录，然后使用输入(文件夹)，输出-文件名
的参数调用ffmpeg
我使用每个循环来访问在列表框中输入的不同目录.然后为每个目录调用ffmpeg.exe.

现在出现了问题，我为列表框中的每个目录创建了一个bmp文件夹
然后我打电话给ffmpeg，将图像转换为电影，然后删除文件夹.我想要的是仅在进程退出时才删除该文件夹，因为该文件夹在中途被删除并且并非所有图像都被转换.

如何知道转换完成后何时退出流程?

I am stuck in a problem in calling a command-line application through a button-click code.

the application is ffmpeg.
my application is to convert pdf docs to images to movie files.
I first create a temp directory for copying images, and then call ffmpeg with the arguments of input (folder), output - file name

i use for each loop for accessing different directories entered in a listbox. then for each directory i call ffmpeg.exe.

now comes the problem, for each directory in listbox i create a bmp folder
then i call ffmpeg , convert the images to movie, and delete the folder. What i want is the folder to be deleted only when the process has exited, because the folder gets deleted in midway and not all the images are converted.

How do i know when the process has exited after completing the conversion?

Dim pathmviasf As String = "c:\Aio-Pdf-Batch\Movies\Asf\"
Dim pathmvitmp As String = System.IO.Path.GetDirectoryName(Application.ExecutablePath) & "\Bmp\"

For cnt As Integer = 0 To ListBoxControl1.Items.Count - 1
                If Directory.Exists(pathmvitmp) Then
                    Directory.Delete(pathmvitmp, True)
                    Directory.CreateDirectory(pathmvitmp)
                Else
                    Directory.CreateDirectory(pathmvitmp)
                End If
                Dim i As Integer
                pdffile1 = PDFFile.Open(ListBoxControl1.Items(cnt))
                For i = 0 To pdffile1.PageCount - 1
                    Dim pageImage As Bitmap = pdffile1.GetPageImage(i, 96)
                    pageImage.Save(String.Format(pathmvitmp & "page{0}.bmp", i), ImageFormat.Bmp)
                Next i
                strfil = pathmviasf & IO.Path.GetFileNameWithoutExtension(ListBoxControl1.Items(cnt)) & "\"
                If Not Directory.Exists(strfil) Then
                    Directory.CreateDirectory(strfil)
                Else
                    Directory.Delete(strfil, True)
                    Directory.CreateDirectory(strfil)
                End If
                Dim videoPath As String = strfil & IO.Path.GetFileNameWithoutExtension(ListBoxControl1.Items(cnt)) & ".asf"
                Dim ffmpeg As Process = New Process()
                ffmpeg.StartInfo.RedirectStandardOutput = True
                ffmpeg.StartInfo.UseShellExecute = False
                ffmpeg.StartInfo.Arguments = String.Format(videoPath & " " & 0.5)
                ffmpeg.StartInfo.FileName = "ffmpeg.exe"
                ffmpeg.StartInfo.WindowStyle = ProcessWindowStyle.Hidden
                ffmpeg.Start()
            Next

推荐答案

Start方法返回该过程的句柄，然后可以等待

The Start method returns a handle to the process, you can then wait for it to end.

，您可以在ffmPeg Process对象上使用WaitForExit()方法

http://msdn.microsoft.com/zh-我们/library/system.diagnostics.process.waitforexit%28VS.71%29.aspx [

you could use the WaitForExit() method on the ffmPeg Process object

http://msdn.microsoft.com/en-us/library/system.diagnostics.process.waitforexit%28VS.71%29.aspx[^]

Given WaitForExit() can be an indefinite wait, I''d make sure to add a kill button to your code and use the Kill() method, so they can kill it if they get bored.

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