richtextbox for = i multiple function - vb.net

Question

I am looking for the answer to my question, here I clearly explain the situation to you.
I have a richtextbox, and 10 lines included.
line1
line2
line3
line4
line5
..
line10
and i am doing this;
For i = 0 to richtextbox.Lines.Count = - 1
Button1_Click;
Dim getlist as Process = Process.Start("cmd", "commands" + richtextbox.Lines(i))
getlist.WaitForExit()
Next
I tried this but it didn't work;
Dim getlist as Process = Process.Start("cmd", "commands" + richtextbox.Lines(i))
Dim getlist2 as Process = Process.Start("cmd", "commands" + richtextbox.Lines(i + 1))
when I do this, it gets like;
first: richtextbox line 0 and line 1
and getlist starts line1 and getlist2 starts line2
I want it to be like;
getlist: line0
getlist2: line1
and who finishes earlier, the function starts to get new line;
for example:
getlist: line0-line2-line3-line5
getlist2: line1-line4-line6
how could I do this? thanks a lot for all answers!

Answer 1

In order to do this, you'll need to use some sort of threading-based solution to execute in parallel. Probably the most straightforward of these is to use Task-based asynchronous methods.
This would end up looking something like this:
Dim T1 = Task.Run(Sub()
Dim getlist as Process = Process.Start("cmd", "commands" & richtextbox.Lines(1))
getlist.WaitForExit()
End Sub)
Dim T2 = Task.Run(Sub()
Dim getlist as Process = Process.Start("cmd", "commands" & richtextbox.Lines(2))
getlist.WaitForExit()
End Sub)
Then, you would be able to use various approaches to wait for one or both tasks to finish. If you mark the containing routine as Async you could Await either T1 or T2. You can also Await Task.WhenAny to continue as soon as either one finishes.
I would strongly recommend reading the MSDN documentation on Task-based asynchrony. In particular, you should read "Implementing the Task-based Asynchronous Pattern", as the sections on Interleaving and Throttling are likely to be applicable to what you want to do. Unfortunately, the examples are all in C# in my copy of the online help, but the material should be straightforward to translate to VB.

Answer 2

If I understand your intention, this is the perfect application for threading. This works - I just wrote it, compiled it and ran it. To see it do some simple tasks in separate threads, running just 2 threads at a time until all commands have been executed, just enter valid shell commands into your richtextbox1. To test it, I used:
Echo A
Echo B
Echo C
Echo D
NOTES:
I appended a PAUSE into the CMD arguments, so you can see clearly what's happening.
Threading has a lot of nuances that I can't begin to get into here such as ApartmentState, but it's something that you'll want to educate yourself about.
I'm no guru, and I'm sure there are some more elegant ways to handle some of this 😄
Hope this helps!
Imports System.Threading
Public Class Form1
Dim Thread1 As Thread
Dim Thread2 As Thread
Dim Thread1cmd As String = ""
Dim Thread2cmd As String = ""
Dim Thread1Running As Boolean = False
Dim Thread2Running As Boolean = False
Dim LastCmd As Int32 = -1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
LastCmd = -1
While LastCmd < RichTextBox1.Lines.Count
If Thread1Running = False And (LastCmd + 1) < RichTextBox1.Lines.Count Then
LastCmd += 1
Thread1cmd = RichTextBox1.Lines(LastCmd)
output.Text += LastCmd.ToString + " Thread 1: " + Thread1cmd + vbCrLf
Thread1 = New Thread(AddressOf Thread1Helper)
Thread1.IsBackground = True
Thread1.Start()
End If
If Thread2Running = False And (LastCmd + 1) < RichTextBox1.Lines.Count Then
LastCmd += 1
Thread2cmd = RichTextBox1.Lines(LastCmd)
output.Text += LastCmd.ToString + " Thread 2: " + Thread2cmd + vbCrLf
Thread2 = New Thread(AddressOf Thread2Helper)
Thread2.IsBackground = True
Thread2.Start()
End If
'Note - there is debate around the DoEvents that follows, so experiment with it and see what works best for you
Application.DoEvents()
'the main thread now sleeps to give helper threads time to do some work:
System.Threading.Thread.Sleep(200)
End While
End Sub
Sub Thread1Helper()
Thread1Running = True
Dim p1 As System.Diagnostics.Process
Try
p1 = New System.Diagnostics.Process
Dim MyCMD As String = Environment.GetFolderPath(Environment.SpecialFolder.System) + "\cmd"
p1.StartInfo.FileName = MyCMD
p1.StartInfo.Arguments = " /c " + """" + Thread1cmd + "&&PAUSE" + """"
'MsgBox(p1.StartInfo.FileName.ToString)
p1.Start()
p1.WaitForExit()
p1.Close()
Catch ex As Exception
MsgBox(ex.ToString)
End Try
Thread1Running = False
End Sub
Sub Thread2Helper()
Thread2Running = True
Dim p2 As System.Diagnostics.Process
Try
p2 = New System.Diagnostics.Process
Dim MyCMD As String = Environment.GetFolderPath(Environment.SpecialFolder.System) + "\cmd"
p2.StartInfo.FileName = MyCMD
p2.StartInfo.Arguments = " /c " + """" + Thread2cmd + "&&PAUSE" + """"
'MsgBox(p2.StartInfo.FileName.ToString)
p2.Start()
p2.WaitForExit()
p2.Close()
Catch ex As Exception
MsgBox(ex.ToString)
End Try
Thread2Running = False
End Sub
End Class