To make an application to run in Background, you need the application to run in a context that inherits from ApplicationContext
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Here are the steps to create this
1- Start a new project as a window Form application
2- Add a class and make this class to inherits from ApplicationContext
3- in your class, add a Protected Shared Sub Main
It should look like this at this point
Friend Class BGApplication : Inherits ApplicationContext
Protected Shared Sub main()
Application.Run(New BGApplication)
End Sub
End Class
4- go to the project properties, in the "Application" tab and uncheck the check box "Enable Application Framework"
5- In the same tab, expand "Startup Object" and click your Application context class name ( From the above example, "BGApplication"
6- Now go to the Solution Explorer and delete Form1.Vb
At this point you have created all the context for the application to run in background.
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You are not saying what your application does, if it runs on a timer, just add a timer in your class BGApplication
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Sometime we like to create some background application to do something in response of hot keys.
To react on hotkeys, an application should be able to access its message loop. The class ApplicationContext does not provide any way to do it. However, it is possible to do it indirectly by using a control as loop accessor.
The idea is to create a class that inherits from Control and access the application message loop thru this control.
Here an example. this application runs in background. When CTRL-A is pressed, the application starts IExplorer and navigate to this forum. When CTRL-Q is pressed, the application exits.
Friend Class BGApplication : Inherits ApplicationContext
Protected Shared Sub main()
Application.Run(New BGApplication)
End Sub
Private WithEvents pumpAccessor As MessagePumpAccessor
Sub New()
pumpAccessor = New MessagePumpAccessor
Native.RegisterHotKey(pumpAccessor.Handle, 1, Native.MOD_CONTROL, Keys.A)
Native.RegisterHotKey(pumpAccessor.Handle, 2, Native.MOD_CONTROL, Keys.Q)
End Sub
Private Sub Ctrl_A_Pressed(Sender As Object, e As EventArgs) Handles pumpAccessor.Ctrl_A_Pressed
Process.Start("iexplore.exe", "http://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=vbgeneral")
End Sub
Private Sub Ctrl_Q_Pressed(Sender As Object, e As EventArgs) Handles pumpAccessor.Ctrl_Q_Pressed
Native.UnregisterHotKey(pumpAccessor.Handle, 1)
Native.UnregisterHotKey(pumpAccessor.Handle, 2)
Me.ExitThread()
End Sub
End Class
Friend Class MessagePumpAccessor : Inherits Control
Public Event Ctrl_A_Pressed As EventHandler
Public Event Ctrl_Q_Pressed As EventHandler
Protected Overrides Sub WndProc(ByRef m As Message)
If m.Msg = Native.WM_HOTKEY Then
If m.WParam = CType(1, IntPtr) Then
RaiseEvent Ctrl_A_Pressed(Me, EventArgs.Empty)
ElseIf m.WParam = CType(2, IntPtr) Then
RaiseEvent Ctrl_Q_Pressed(Me, EventArgs.Empty)
End If
End If
MyBase.WndProc(m)
End Sub
End Class
Public Class Native
Public Declare Function RegisterHotKey Lib "user32" (ByVal hwnd As IntPtr, ByVal id As Integer, ByVal fsModifiers As Integer, ByVal vk As Integer) As Integer
Public Declare Function UnregisterHotKey Lib "user32" (ByVal hwnd As IntPtr, ByVal id As Integer) As Integer
Public Const WM_HOTKEY As Integer = &H312
Public Const MOD_CONTROL = &H2
End Class
