EXE and parameters ?

Hi,

If you are using VB 2005, there is a very easy way to pass in command line arguments to the .EXE. Here is some code that lives in the MyProject code behind file for the Card Game Starter Kit (this sample ships in VB 2005!):

Class MyApplication #If _MyType = "WindowsForms" Then Private Sub MyApplication_Startup(ByVal sender As Object, ByVal e As ApplicationServices.StartupEventArgs) Handles Me.Startup If e.CommandLine.Count > 0 Then ' Get the 2 character command line argument Dim arg As String = e.CommandLine(0).ToLower(System.Globalization.CultureInfo.InvariantCulture).Trim().Substring(0, 2) Select Case arg Case "/c" ' Show the options dialog Me.MainForm = My.Forms.OptionsForm Case "/p" ' Don't do anything for preview Case "/s" Me.MainForm = My.Forms.ScreenSaverForm Case Else MessageBox.Show("Invalid command line argument :" + arg, "Invalid Command Line Argument", MessageBoxButtons.OK, MessageBoxIcon.Error) End Select Else ' If no arguments were passed in, show the screensaver Me.MainForm = My.Forms.ScreenSaverForm End If End Sub

If you are using VB 2002 or 2003, you will write similar code in a custom Sub Main. Define a Sub Main in a Startup.VB module, and choose this Sub main as your startup object in the project properties.

Here is a code sample from vb-helper.com http://www.vb-helper.com/howto_net_list_command_line_arguments.html>:

Module StartupModule Public Function Main(ByVal CmdArgs() As String) As _ Integer Dim frm As New Form1() Dim i As Integer frm.Text = UBound(CmdArgs) + 1 & " arguments" For i = 0 To UBound(CmdArgs) frm.lstCommands.Items.Add(CmdArgs(i)) Next i frm.ShowDialog() Return 0 End Function End Module

Hope this helps.

Best,

Paul Yuknewicz
Visual Basic

PaulYuk_MS at 2007-9-9 >

I have a related question at

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=600652&SiteID=1

how do you make an application the only instance that can be running and when you double click a file that's assiciated with the application it opens in the already running instance?

Windows Media Player does this with songs, you can only have one instance of media player running but when you click a song it strikes something in the already running instance and it plays?

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim cmd As String = Microsoft.VisualBasic.Command

End Sub

I tried Microsoft.VisualBasic.Command in Me.Load, it works the first time but after you make the program a single instance application by clicking on myproject in solution explorer it doesn't change the command line argument the second time you click the shortcut like testprogram.exe parameter. Anybody know how to clear it or something? It's still only seeing the first parameter i put in, the doesnt change when i run the single instance application for the second time.

Thanks

JohnX.C. at 2007-9-9 >

Once you use the 2005 framework, passing the parameter is easy. In your ApplicationEvents, add a handler for the StartupNextInstance event. The below code takes the CommanLineArgs from the next instance, wraps them up in the same format as the original args and passes it on to the main form for processing.

Private Sub MyApplication_StartupNextInstance(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupNextInstanceEventArgs) Handles Me.StartupNextInstance

If TypeOf Me.MainForm Is Form1 Then

Dim Args(e.CommandLine.Count) As String

DirectCast(Me.MainForm, Form1).showArgs(Args)

End If

End Sub

There is a working demo and write-up at http://devauthority.com/blogs/jwooley/archive/2005/07/28/318.aspx

I hope this helps.

Jim Wooley
http://devauthority.com/blogs/jwooley

jwooley at 2007-9-9 >