Tag Archives: .NET

Emulating keyboard events in .NET

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Every now and then, you may need to emulate pressing keys on a keyboard to accomplish things through code. I found I needed to utilize this method for an Outlook programming project. After a little searching, I was able to emulate a user pressing the “ALT” button twice. You can use the keybd_event function (http://msdn2.microsoft.com/en-us/library/ms646304.aspx) to emulate keyboard events:

Imports System.Runtime.InteropServices

‘List of virtual key codes: http://msdn2.microsoft.com/en-us/library/ms645540.aspx
Const VK_SHIFT = &H10
Const VK_NUMLOCK = &H90
Const VK_ESC = &H1B
Const VK_MENU = &H12 ‘This is the ALT key
Const KEYEVENTF_KEYUP As Integer = &H2

<DllImport(“user32”)> _
Public Sub keybd_event(ByVal vk As Byte, ByVal sc As Byte, ByVal Flags As Integer, ByVal dwExtraInfo As Integer)
End Sub

Public Sub PressAltKeyTwice()
‘Simulate Key Press
keybd_event(VK_MENU, vbNull, 0, 0)
‘Simulate Key Release
keybd_event(VK_MENU, vbNull, KEYEVENTF_KEYUP, 0)

Application.DoEvents() ‘This was needed in my code to register the first keypress. If I did not have this, the system acted as though I press it only once.

‘Simulate Key Press
keybd_event(VK_MENU, vbNull, 0, 0)
‘Simulate Key Release
keybd_event(VK_MENU, vbNull, KEYEVENTF_KEYUP, 0)

Application.DoEvents()

End Sub

Enabling two-way communication between javascript and parent WebBroswer class

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When I began looking for a way to do this, I thought it was going to be very difficult. What I wanted, was a javascipt method inside a WebBrowser object hosted in a Custom Task Pane, to call a method in the parent object’s class that would then call a method in the web page view of a folder, which would then execute client-side javascript inside that HTML document object. Fortunately, this is a very easy task by utilizing two methods: window.external and HTMLDoc.parentWindow.execScript.

Getting a client-side javascript method to invoke a method inside the parent class is as simple as using:

– In the HTML code:

<a href=”http://blogs.orcsweb.com/ControlPanel/Blogs/posteditor.aspx?SelectedNavItem=NewPost#&#8221; onclick=”javascript:window.external.MyMethod(var1, var2);”>Invoke MyMethod</a>

– In parent object’s class

Public Sub MyMethod(ByVal var1 As String, ByVal var2 As String)
MsgBox(“Var1: ” & var1 & “, Var2: ” & var2)
End Sub

In Outlook, if the current folder is set to use a web view instead of the standard folder list, the Application.ActiveExplorer.HTMLDocument reference will contain a valid mshtml.HTMLDocument object (it will throw an exception otherwise). Executing client-side javascript (or vbscript in my case) is as easy as calling the parentWindow.execScript method:

Dim oHTMLDoc As mshtml.HTMLDocument

oHTMLDoc = Application.ActiveExplorer.HTMLDocument

oHTMLDoc.parentWindow.execScript(“ClientSideMethod(‘” & Var1 & “‘,'” & var2 & “‘)”)

The point of doing this is that the web page view of the folder contains an Outlook View Control object, and using the above methods, we are able to set the “Restriction” property of the object from a web page hosted inside a custom task pane.