如何在运行时使用vb.net 2012将控制台应用程序的输出重定向到Windows窗体上的Textbox控件

Question

Team,

I have an third party application which actually is a telephonic messaging server and exchange messages between all connected clients and other servers. This messaging server keeps running for several days and even for moths. This is entirely a console application and do not have any GUI. Even to manage the internal operations of this server, there is another tool which is a console based application again. I would like to prepare a GUI to start, stop and restart this server in VB.Net 2012. I have managed to,

1. Create the process instance of this server

2. Launch the Server with appropriate parameters and keep it running. Below is some sample code from my application to launch the server,

   Private Sub Server_Start_Click(sender As Object, e As EventArgs) Handles Server_Start.Click Dim parameter, server_admin_path As String server_admin_path = "D:\\Voice_App\\DataMessage\\MessageServer.exe" parameter = " -properties " & """" & " D:\\Voice_App\\Config\\message.prop"

    Dim proc = New Process() proc.StartInfo.FileName = server_admin_path proc.StartInfo.Arguments = parameter ' set up output redirection proc.StartInfo.RedirectStandardOutput = True proc.StartInfo.RedirectStandardError = True proc.EnableRaisingEvents = True Application.DoEvents() proc.StartInfo.CreateNoWindow = False proc.StartInfo.UseShellExecute = False ' see below for output handler AddHandler proc.ErrorDataReceived, AddressOf proc_OutputDataReceived AddHandler proc.OutputDataReceived, AddressOf proc_OutputDataReceived proc.Start() proc.BeginErrorReadLine() proc.BeginOutputReadLine() 'proc.WaitForExit() Server_Logs.Focus() 

   End sub

This code launches the message server very well. The message server is now started and it is producing log traces on the console after specific time of interval say 30 seconds and this will be continue till message server is not stopped by administration tool. So now what I want is to capture every single line that is being produced by my server on its console and paste that line on to the Textbox I have on my windows form.

I got below code which gives me that every line as and when produced,

   Public Sub proc_OutputDataReceived(ByVal sender As Object, ByVal e As                     DataReceivedEventArgs)
    On Error Resume Next
    ' output will be in string e.Data
    ' modify TextBox.Text here
    'Server_Logs.Text = e.Data  ` Does not display anything in textbox
    MsgBox(e.Data) 'It works but I want output in text box field
End Sub

PS = My application will be handling more that one such servers and I don't want users to have every message server instance open on their taskbar as console window and they are scrolling long log traces. I searched lots of threads here but nothing worked for me in above scenario. Any help would be greatly appreciated as I have been stuck on this since very long time and this is now a showstopper!!!!

Answer 1

Looks like you are trying to make a call from a thread that is different from the thread the form is on. The events raised from the Process class will not be from the same thread.

Delegate Sub UpdateTextBoxDelg(text As String)
Public myDelegate As UpdateTextBoxDelg = New UpdateTextBoxDelg(AddressOf UpdateTextBox)

Public Sub UpdateTextBox(text As String)
    Textbox.Text = text
End Sub

Public Sub proc_OutputDataReceived(ByVal sender As Object, ByVal e As DataReceivedEventArgs)

    If Me.InvokeRequired = True Then
        Me.Invoke(myDelegate, e.Data)
    Else
        UpdateTextBox(e.Data)
    End If

End Sub