How to use command lines in vb.net - vb.net

Question

I m developing a windows application that will use pdf2text pilot software which supports command line. In this application user needs to specify location of the pdf file. I m able to open cmd but could not pass commands to it or somehow my commands are not getting executed.
Imports System
Imports System.IO
Imports System.Diagnostics.Process
Imports System.Diagnostics.ProcessStartInfo
Public Class EDCS
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim dlgrslt As DialogResult = OpenFileDialog1.ShowDialog()
Dim fnames As String() = OpenFileDialog1.FileNames
Dim txtfnames As String
For i = 0 To fnames.Length - 1
If TextBox1.Text = "" Then
TextBox1.Text = fnames(i)
Else
TextBox1.Text = TextBox1.Text + " / " + fnames(i)
End If
txtfnames = fnames(i).Replace(".pdf", ".txt")
File.Create(txtfnames).Dispose()
Dim convertcommand As String = "textextract """ & fnames(i) & """ /to """ & txtfnames & """"
'/c will exit cmd and /k will keep it open
'Shell("cmd.exe /c textextract "C:\Users\user\Desktop\ Part 1.pdf" /to " C:\Users\user\Desktop\ Part 1.txt"")
'SendKeys.Send(convertcommand)
'SendKeys.Send("{ENTER}")
Dim p As New Process
p.StartInfo.FileName = "cmd.exe"
'p.StartInfo.WorkingDirectory = "C:\Program Files (x86)\Two Pilots\PDF2Text Pilot"
'p.StartInfo.Arguments = "textextract "C:\Users\user\Desktop\ Part 1.pdf" /to " C:\Users\user\Desktop\ Part 1.txt""
p.StartInfo.UseShellExecute() = False
p.StartInfo.RedirectStandardInput = True
p.StartInfo.RedirectStandardOutput = True
p.Start()
p.StandardInput.WriteLine(convertcommand)
'Dim process As New Process()
'process.StartInfo.FileName = "cmd.exe "
'process.StartInfo.Verb = "runas"
'process.StartInfo.UseShellExecute = False
'process.StartInfo.RedirectStandardInput = True
'process.StartInfo.RedirectStandardOutput = True
'process.Start()
'process.StandardInput.WriteLine("textextract "C:\Users\user\Desktop\ Part 1.pdf" /to " C:\Users\user\Desktop\ Part 1.txt"")
'process.StandardInput.WriteLine("exit")
'process.Close()
Next
End Sub
End Class
OS: Windows 7
vb.net developer
Thanks in Advance

Answer 1

OK, here you go, this should work, turns out that pdf2text has a bug in it, but I managed to get it working by passing a couple of blank lines before the command runs and then also adding a wait for the utility to complete before the command prompt closes. You may need to increase that wait for large files I guess. I get some "The handle is invalid" messages in the command prompt and I suspect they are from pdf2text too, but it looks like its safe to ignore them.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dlgrslt As DialogResult = OpenFileDialog1.ShowDialog()
Dim fnames As String() = OpenFileDialog1.FileNames
Dim txtfnames As String
For i = 0 To fnames.Length - 1
If TextBox1.Text = "" Then
TextBox1.Text = fnames(i)
Else
TextBox1.Text = TextBox1.Text + " / " + fnames(i)
End If
txtfnames = fnames(i).Replace(".pdf", ".txt")
File.Create(txtfnames).Dispose()
Dim convertcommand As String = "textextract.exe """ & fnames(i) & """ /to """ & txtfnames & """"
Dim p As New Process
p.StartInfo.FileName = "cmd.exe"
p.StartInfo.Arguments = " /k"
p.StartInfo.UseShellExecute = False
p.StartInfo.RedirectStandardInput = True
p.StartInfo.RedirectStandardOutput = False
p.Start()
Using sw As StreamWriter = p.StandardInput
If sw.BaseStream.CanWrite Then
sw.WriteLine()
sw.WriteLine()
sw.WriteLine(convertcommand)
p.WaitForExit(3000)
End If
End Using
Next
End Sub