VB.Net Send output and input of process started in another form - vb.net

Question

I have 2 forms, MainForm and RCONForm.
What I am trying to do is to start a process when the programs starts and in this case I have choosen cmd.exe and it works.
The thing is I want to be able to read the output and send input onto the process from another form using 2 textboxes.
The problem is that I can't read anything from the process neither can I send any input to it either.
My MainForm:
Public Class MainForm
#Region "Import Function"
Dim Functions As New Functions
Friend WithEvents RCON As Process
#End Region
Friend Sub AppendOutputText(ByVal text As String)
If RCONForm.RCONLogText.InvokeRequired Then
Dim myDelegate As New RCONForm.AppendOutputTextDelegate(AddressOf AppendOutputText)
Me.Invoke(myDelegate, text)
Else
RCONForm.RCONLogText.AppendText(text)
End If
End Sub
Private Sub MainForm_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
RCON = New Process
With RCON.StartInfo
.FileName = "C:\Windows\system32\CMD.exe"
.UseShellExecute = False
.CreateNoWindow = True
.RedirectStandardInput = True
.RedirectStandardOutput = True
.RedirectStandardError = True
End With
RCON.Start()
RCON.BeginErrorReadLine()
RCON.BeginOutputReadLine()
AppendOutputText("RCON Started at: " & RCON.StartTime.ToString)
End Sub
Private Sub RCONButton_Click(sender As Object, e As EventArgs) Handles RCONButton.Click
Functions.KillOldForm()
Functions.SpawnForm(Of RCONForm)()
End Sub
Private Sub ExitButton_Click(sender As Object, e As EventArgs) Handles ExitButton.Click
Application.Exit()
End Sub
Private Sub ServerButton_Click(sender As Object, e As EventArgs) Handles ServerButton.Click
Functions.KillOldForm()
Functions.SpawnForm(Of ServerForm)()
End Sub
End Class
And my RCONForm:
Public Class RCONForm
Friend Delegate Sub AppendOutputTextDelegate(ByVal text As String)
Friend WithEvents RCON As Process = MainForm.RCON
Friend Sub RCON_ErrorDataReceived(ByVal sender As Object, ByVal e As System.Diagnostics.DataReceivedEventArgs) Handles RCON.ErrorDataReceived
MainForm.AppendOutputText(vbCrLf & "Error: " & e.Data)
End Sub
Friend Sub RCON_OutputDataReceived(ByVal sender As Object, ByVal e As System.Diagnostics.DataReceivedEventArgs) Handles RCON.OutputDataReceived
MainForm.AppendOutputText(vbCrLf & e.Data)
End Sub
Friend Sub RCONCommandText_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles RCONCommandText.KeyPress
If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Return) Then
MainForm.RCON.StandardInput.WriteLine(RCONCommandText.Text)
MainForm.RCON.StandardInput.Flush()
RCONCommandText.Text = ""
e.Handled = True
End If
End Sub
Friend Sub RCONForm_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
MainForm.RCON.StandardInput.WriteLine("EXIT") 'send an EXIT command to the Command Prompt
MainForm.RCON.StandardInput.Flush()
MainForm.RCON.Close()
End Sub
Private Sub RCONForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
End Class
My Functions:
#Region "Kill Old Forms"
Function KillOldForm()
While MainForm.SpawnPanel.Controls.Count > 0
MainForm.SpawnPanel.Controls(0).Dispose()
End While
Return Nothing
End Function
#End Region
#Region "Spawn Form"
Function SpawnForm(Of T As {New, Form})() As T
Dim spawn As New T() With {.TopLevel = False, .AutoSize = False}
Try
spawn.Dock = DockStyle.Fill
MainForm.SpawnPanel.Controls.Add(spawn)
spawn.Show()
Catch ex As Exception
MsgBox(ex.Message)
End Try
Return Nothing
End Function
#End Region
I have been thinking of using threads and maybe that can solve the issue, or is there a more simple way?

Answer 1

You are using default form instances heavily. You should avoid that if possible. Here's a way to keep track of the proper instance of RCONForm in MainForm
Private myRCONForm As RCONForm
Private Sub RCONButton_Click(sender As Object, e As EventArgs) Handles RCONButton.Click
Functions.KillOldForm()
myRCONForm = Functions.SpawnForm(Of RCONForm)()
End Sub
Now SpawnForm is a function, and it would return the form so you can keep a reference to it
Public Function SpawnForm(Of T As {New, Form})() As T
Dim myForm = New T()
' add myForm to the appropriate Panel or whatever
Return myForm
End Function
Update all access to RCONForm with myRCONForm in MainForm
Also, this is a little flawed, where you check if invocation is required on RCONForm.RCONLogText, then invoke on Me. It can be simplified
' old with default form instance
Friend Sub AppendOutputText(ByVal text As String)
If RCONForm.RCONLogText.InvokeRequired Then
Dim myDelegate As New RCONForm.AppendOutputTextDelegate(AddressOf AppendOutputText)
Me.Invoke(myDelegate, text)
Else
RCONForm.RCONLogText.AppendText(text)
End If
End Sub
' new, with instance reference plus simplified invocation
Friend Sub AppendOutputText(text As String)
If myRCONForm.RCONLogText.InvokeRequired Then
myRCONForm.RCONLogText.Invoke(New Action(Of String)(AddressOf AppendOutputText), text)
Else
myRCONForm.RCONLogText.AppendText(text)
End If
End Sub