I have a VB.net program in which I call the Shell function. I would like to get the text output that is produced from this code in a file. However, this is not the return value of the executed code so I don't really know how to.
This program is a service but has access to the disk no problem as I already log other information. The whole service has multiple threads so I must also make sure that when the file is written it's not already accessed.
You won't be able to capture the output from Shell.
You will need to change this to a process and you will need to capture the the Standard Output (and possibly Error) streams from the process.
Here is an example:
Dim oProcess As New Process()
Dim oStartInfo As New ProcessStartInfo("ApplicationName.exe", "arguments")
oStartInfo.UseShellExecute = False
oStartInfo.RedirectStandardOutput = True
oProcess.StartInfo = oStartInfo
oProcess.Start()
Dim sOutput As String
Using oStreamReader As System.IO.StreamReader = oProcess.StandardOutput
sOutput = oStreamReader.ReadToEnd()
End Using
Console.WriteLine(sOutput)
To get the standard error:
'Add this next to standard output redirect
oStartInfo.RedirectStandardError = True
'Add this below
Using oStreamReader As System.IO.StreamReader = checkOut.StandardError
sOutput = oStreamReader.ReadToEnd()
End Using
Just pipe the output to a text file?
MyCommand > "c:\file.txt"
Then read the file.
Dim proc As New Process
proc.StartInfo.FileName = "C:\ipconfig.bat"
proc.StartInfo.UseShellExecute = False
proc.StartInfo.RedirectStandardOutput = True
proc.Start()
proc.WaitForExit()
Dim output() As String = proc.StandardOutput.ReadToEnd.Split(CChar(vbLf))
For Each ln As String In output
RichTextBox1.AppendText(ln & vbNewLine)
lstScan.Items.Add(ln & vbNewLine)
Next
=======================================================================
create a batch file in two lines as shown below:
echo off
ipconfig
' make sure you save this batch file as ipconfig.bat or whatever name u decide to pick but make sure u put dot bat at the end of it.
Related
I'm trying to create a VB.NET application which writes multiple lines of text into a text file, then starts an application and after the application started, deletes the text file.
How exactly can I realize that?
--
Edit:
I now got this code:
Dim iniFile As String = Application.StartupPath + "\settings.ini"
If System.IO.File.Exists(iniFile) = True Then
File.Delete(iniFile)
End If
If System.IO.File.Exists(iniFile) = False Then
File.Create(iniFile)
End If
Dim fileStr As String() = {"line1", "line2", "line3"}
File.WriteAllLines(iniFile, fileStr)
Dim p As Process = Process.Start(Application.StartupPath + "\app.exe")
p.WaitForInputIdle()
If System.IO.File.Exists(iniFile) = True Then
File.Delete(iniFile)
End If
The only problem I got, is that VS is telling me, the file is in use. Between creating and editing the file. Any ideas for that?
Your code is starting the app and then moving straight on to delete the ini file.
You need to wait for the process to exit first before you continue with deleting the ini file
E.g
{code to create ini file}
'Start the process.
Dim p As Process = Process.Start(Application.StartupPath + "\app.exe")
'Wait for the process window to complete loading.
p.WaitForInputIdle()
'Wait for the process to exit.
p.WaitForExit()
{code to delete ini file}
Full example here: https://support.microsoft.com/en-us/kb/305368
Just use File.WriteAllText
Note: As others already mentioned, you should check against True in your last If
If System.IO.File.Exists(Application.StartupPath + "\settings.ini") = False Then
File.Create(Application.StartupPath + "\settings.ini")
End If
Dim fileStr As String() = {"line1", "line2", "line3"}
System.IO.File.WriteAllText(Application.StartupPath + "\settings.ini", [String].Join(Environment.NewLine, fileStr))
Process.Start(Application.StartupPath + "\app.exe")
If System.IO.File.Exists(Application.StartupPath + "\settings.ini") = True Then
File.Delete(Application.StartupPath + "\settings.ini")
End If
Use File.WriteAllLines since it
Creates a new file, write the specified string array to the file, and then closes the file. [...] If the target file already exists, it is overwritten.
msdn
Also you should use Path.Combine to setup your path
Dim path as String = Path.Combine(Application.StartupPath, "settings.ini")
Dim fileStr As String() = {"line1", "line2", "line3"}
File.WriteAllLines(path, fileStr)
Use the Path.Combine for the Process.Start and File.Delete too.
I am trying to create and run a batch file from VB.net, then get the output and print it out. But when it runs it is appended by these symbols '´╗┐. Causing this error '´╗┐cd' is not recognized as an internal or external command, operable program or batch file. When I look at the batch file in notepad++ there is no symbol there! What is happening! Thanks James.
Code:
Dim path As String = Directory.GetCurrentDirectory()
Dim command As String = "cd " & path & " & " & argument
MsgBox(command)
Dim file As System.IO.StreamWriter
file = My.Computer.FileSystem.OpenTextFileWriter(tempFile, False)
file.WriteLine("#ECHO OFF")
file.WriteLine(command)
file.Close()
Dim objProcess As New Process()
Dim SROutput As System.IO.StreamReader
With objProcess.StartInfo
.FileName = tempFile
.RedirectStandardOutput = True
.UseShellExecute = False
.Arguments = ""
End With
objProcess.Start()
SROutput = objProcess.StandardOutput
Do While SROutput.Peek <> -1
'MessageBox.Show(SROutput.ReadLine)
rtbOutput.Text = rtbOutput.Text & SROutput.ReadLine & vbNewLine
Loop
objProcess.Dispose()
'Process.Start(tempFile)
rtbOutput.Text = rtbOutput.Text & message & vbNewLine
That's a Byte Order Mark.
It means the OpenTextFileWriter() method is using a different encoding than you expect. You can fix the problem by using OpenTextFileWriter() overload that allows you pick an encoding like ASCII with no byte order mark or use the encoding with the byte order mark that matches what the DOS subsystem is expecting.
Solved, Im not entirely sure what was happening when it was writing the file, but I have changed it to this
Using writer As StreamWriter = New StreamWriter(tempFile)
writer.Write(command)
End Using
and its now running fine!. Thanks for any time spent on this and feel free to post an explination as to why this was happening.
What's the best way to get the DNS Cache in Visual Basic and returning recently resolved domains? I only need the domains to compare them whit a list.
Function GetDnsCache()
Dim DNSCache As New Process
DNSCache.StartInfo.FileName = "ipconfig"
DNSCache.StartInfo.Arguments = "/displaydns "
DNSCache.StartInfo.UseShellExecute = False
DNSCache.StartInfo.RedirectStandardOutput = True
DNSCache.
DNSCache.Start()
MsgBox(DNSCache.StandardOutput.ReadToEnd())
DNSCache.WaitForExit()
End Function
This is not the cleanest way of doing this and it also takes ages to parse and load.
I would do something like this. It executes ipconfig /displaydns and appends the output to a file. Then, the file is read line by line and displayed wherever you want (I've used a Listbox)
Dim Shell = CreateObject("Wscript.Shell")
Shell.run("cmd /c ipconfig /displaydns >> C:\ipconfig.txt")
Using reader As New IO.StreamReader("C:\ipconfig.txt")
While Not reader.EndOfStream
Dim currentLine As String = reader.ReadLine()
ListBox1.Items.Add(currentLine)
End While
End Using
Should you like to display the info into a MsgBox...
Dim Shell = CreateObject("Wscript.Shell")
Shell.run("cmd /c ipconfig /displaydns >> C:\ipconfig.txt")
Dim reader as As New IO.StreamReader("C:\ipconfig.txt")
MsgBox(reader.ReadToEnd.ToString, MsgBoxStyle.Information)
Lets just say we have this as Command1
Dim Command1 = "whoami.exe >> C:\Hello.Txt"
The program will read a list of users from a text file and then perform the action on each of them. If the user does not exist, or they are part of a password protected computer, I would like to see that in my printout.
I have this but am Unsure how to write the If Then Statement (If that is the ebst route to take)
For Each strUserName as String in strLines
Shell("cmd.exe /c" & Command1)
If Command1 = fail??
Then msgbox("Oops") ???
If you want to redirect the output of 'whoami.exe' to your own console, you can do the following:
Dim startInfo As New ProcessStartInfo()
startInfo.Arguments = "c:\Hello.txt"
startInfo.FileName = "c:\whoami.exe"
startInfo.RedirectStandardOutput = True
startInfo.UseShellExecute = False
Using process As Process = Process.Start(startInfo)
Using stream As StreamReader = process.StandardOutput
Console.Write(stream.ReadToEnd())
End Using
End Using
You will need to import the System.Diagnostics namespace. If 'whoami.exe' returns an exit code you can use, you can also use the Process class to check it by calling:
process.WaitForExit()
Dim code As Integer = process.ExitCode
If code = 1 Then
' success
Else
' other
End If
Hope this helps.
You need to write the If Then statement in either one line or multiple lines ending with an End If
If Command1 = fail Then msgbox("Oops")
or
If Command1 = fail Then
msgbox("Oops")
End If
Here is the msdn documentation for the if statement.
so I've tried Process and starting a cmd.exe and send commands directly to that window. And then picking up the values written to the cmd.exe window.
The code looks like this:
Dim arrServers As ArrayList
Dim s(ListBoxServers.Items.Count) As String
ListBoxServers.Items.CopyTo(s, 0)
arrServers = New ArrayList(s)
Using P As New Process
P.StartInfo.FileName = "cmd.exe"
P.StartInfo.UseShellExecute = False
P.StartInfo.RedirectStandardOutput = True
P.StartInfo.RedirectStandardInput = True
P.Start()
For Each i In arrServers
P.StandardInput.WriteLine("query user " & txtBoxUsername.Text & " /server:" & i)
Next
P.StandardInput.WriteLine("exit")
Output = P.StandardOutput.ReadToEnd()
Trace.WriteLine(Output)
MsgBox(Output)
P.WaitForExit()
End Using
But is looks like it doesn't "press enter" or something. Meaning, I don't get any results from the command. I don't even get a "'command' is not recognized as an internal or external command, operable program or batch file." like you normally get if it doesn't understand the syntax.
Look into the Process class in the System.Diagnostics namespace for running your batch file.
Imagine the following really simple batch file called "hello.bat"
#ECHO OFF
echo Hello
You can call it and see "Hello" by using:
'Will hold the results of the batch
Dim Output As String
'Create a new process object
Using P As New Process()
'Set the script to run
P.StartInfo.FileName = "c:\scripts\hello.bat"
'My script doesn't take argument but this is where you would pass them
P.StartInfo.Arguments = ""
'Required to redirect output, don't both worrying what it means
P.StartInfo.UseShellExecute = False
'Tell the system that you want to see the output
P.StartInfo.RedirectStandardOutput = True
'Start your batch
P.Start()
'Read the entire contents of the outout
Output = P.StandardOutput.ReadToEnd()
'Wait until the batch is done running
P.WaitForExit()
End Using
'Do something with the output
Trace.WriteLine("Batch produced : " & Output)
Edit
Here's a version that doesn't run a batch but instead runs a couple of standard commands. We start by firing up a command shell to pass things to. One thing that sucks is that its hard to run a command, read the output and then run another command. The code below runs two commands back-to-back and dumps the entire result into a string. If you have a need for running a command, processing, running another command, I think you'll have to wire up something to StandardError and look at return codes. Before you do that, make sure you read up on problem with blocking and how other places solve it by wiring threads up such as here. Probably the easier way is to wrap this into a sub and call the sub once for each command.
'Will hold all of the text
Dim Output As String
'Create a new process object
Using P As New Process()
'Set the script to run the standard command shell
P.StartInfo.FileName = "cmd.exe"
'Required to redirect output, don't both worrying what it means
P.StartInfo.UseShellExecute = False
'Tell the system that you want to read/write to it
P.StartInfo.RedirectStandardOutput = True
P.StartInfo.RedirectStandardInput = True
'Start your batch
P.Start()
'Send your various commands
P.StandardInput.WriteLine("dir c:\")
P.StandardInput.WriteLine("ipconfig /all")
'Very important, send the "exit" command otherwise STDOUT will never close the stream
P.StandardInput.WriteLine("exit")
'Read the entire stream
Output = P.StandardOutput.ReadToEnd()
'Wait until the batch is done running
P.WaitForExit()
End Using
'Do something with the output
Trace.WriteLine(Output)
Edit 2
I'm having problems with the "query user" command in general, I can't get it to return anything for usernames with spaces in them even if I enclose the name in quotes. But here's a version that uses "quser" instead which does the exact same thing as far as I know.
'Will hold all of the text
Dim Output As String
'Create a new process object
Using P As New Process()
'Set the script to run the standard command shell
P.StartInfo.FileName = "cmd.exe"
'Required to redirect output, don't both worrying what it means
P.StartInfo.UseShellExecute = False
'Tell the system that you want to read/write to it
P.StartInfo.RedirectStandardOutput = True
P.StartInfo.RedirectStandardInput = True
'Start your batch
P.Start()
'Send your various commands
'Array of servers
Dim arrServers() As String = New String() {"SERVER1", "SERVER2"}
'Loop through array, wrap names with quotes in case they have spaces
For Each S In arrServers
P.StandardInput.WriteLine(String.Format("quser ""{0}"" /SERVER:{1}", Me.txtBoxUsername.Text, S))
Next
'Very important, send the "exit" command otherwise STDOUT will never close the stream
P.StandardInput.WriteLine("exit")
'Read the entire stream
Output = P.StandardOutput.ReadToEnd()
'Wait until the batch is done running
P.WaitForExit()
End Using
'Do something with the output
Trace.WriteLine(Output)
Use a library/class like NDesk's Options for flexible argument handling. If you don't want to use a external component, you'll have to loop over the arguments and process them manually:
For Each arg As String In Environment.GetCommandLineArgs()
Select Case arg
Case "/blah"
' process /blah '
Case "/foo"
' process foo '
Case Else
MsgBox "Unknown argument " + arg " found, aborting.", vbCritical
Environment.Exit(1)
End Select
Next
[I normally don't do VB, so this is just an untested sketch]