WaitForExit() 런타임 예외. (cmd 프로세스가 끝날 때까지 기다리는 중)

Question

이 코드를 실행하려고 할 때 런타임 예외가 발생하는 이유는 무엇입니까?

Sub BtnNowClick(sender As Object, e As EventArgs) 

    Dim myProcess As New Process 
    Dim processFile As String = dlgFolder.SelectedPath 
    Dim pyLocationDel As String = Path.Combine(dlgFolder.SelectedPath, "pdfmerge.py") 

    Directory.SetCurrentDirectory(dlgFolder.SelectedPath) 

    myProcess.Start(pyLocationDel) 
    myProcess.WaitForExit()  
    System.IO.File.Delete(pyLocationDel) 


End Sub 

기본적으로 원하는 것은 프로세스가 완료된 것을 감지하고 프로세스가 완료되면 특정 파일을 삭제하는 것입니다.

System.NullReferenceException: Object reference not set to an instance of an object. 
    at lgaPDF.MainForm.BtnNowClick(Object sender, EventArgs e) in C:\Documents and Settings\student3\My Documents\SharpDevelop Projects\lgaPDF\lgaPDF\MainForm.vb:line 184 
    at System.Windows.Forms.Control.OnClick(EventArgs e) 
    at System.Windows.Forms.Button.OnClick(EventArgs e) 
    at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) 
    at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) 
    at System.Windows.Forms.Control.WndProc(Message& m) 
    at System.Windows.Forms.ButtonBase.WndProc(Message& m) 
    at System.Windows.Forms.Button.WndProc(Message& m) 
    at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) 
    at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) 
    at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) 
    at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) 
    at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData) 
    at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) 
    at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) 
    at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun() 
    at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel() 
    at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine) 
    at lgaPDF.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81 

Answer 1

어떤 Process 인스턴스를 만들 수 없습니다 때문에 : 코드를 실행하려고 할 때

는이 오류를 받고 있어요.

당신이 가변적이고 선언 할 때 생성자를 사용할 수 있습니다 별도의 생성자 호출로

Dim myProcess As New Process() 

: 팁을위한

Dim myProcess As Process 
myProcess = New Process()