need help with a key-logging app

Question

Hi I'm a newbie to C# (so please excuse any improper terminology) and I'm trying to write a simple program that starts with windows runs invisibly in the background and records all of the keystrokes made on the keyboard to a text file. The program also needs a place to input preferences. My questions are: 1. Do I need to create an executable or a windows service. 2. (most importantly) How do I pass information from the keyboard through my program and into a text file (or a database). Currently I'm trying a windows executable that uses a Notify Icon in combination with [this.hide()] to make the windows form invisible. I would really appreciate some help for a beginner and/or any other resources to help out. Thanks all for your time and interest

Ben · Answer

I found this VB code online which says something about being a key logger (I really wouldn't know can't understand the code): Dim result As Integer Private Declare Function GetAsyncKeyState Lib user32 (ByVal vKey As Long) As Integer Private Sub Timer1_Timer() For i = 1 To 255 result = 0 result = GetAsyncKeyState(i) If result = -32767 Then Text1.Text = Text1.Text + Chr(i) End if Next i End Sub Would this code work if it were translated to C#? It also appears that I might be able to somehow use the User32.dll to log keystrokes. Is this true? If so how can I learn more about the User32.dll? Thanks much.

Ben · Answer

Thank you very much jgandara! This is a great start however I am a little confused by the example. Maybe you or someone else can help me. I tried the example and set the opacity of the form to 0. The program would log keys just fine when I used alt+tab to switch to the program (i.e whenever the invisible form was active I could press keys and it would log them). But if I do something like creating a new folder on my desktop and renaming it the program fails to record the keystrokes. Am I missing something in the example? Or is there something else I should be trying? Thanks again for your help!

jrgc6 · Answer

Check this: http://www.c-sharpcorner.com/Code/2002/July/LeyLoggerApp.asp I downloaded the code and created a windows app. It's a little incomplete so you have to map everykeystroke to the correct keyboard key. You can create a class that manages all the code and call it from a windows app or service. Just design it as a class and you are all set.

chrishornberger · Answer

write it in VB using API calls then COM-Interop it to get it started?

Ben · Answer

Microsoft says that the .net framework doesn't support global hooks. What now?

Ben · Answer

chornberger Thanks I'll check it out. I appreciate your time :)

chrishornberger · Answer

Either will work... service or executable. To do what you want will require techniques such as subclassing the WinProc and using Hooks. MSDN has a few examples of how to do system keyboard hooks and I'm sure would be a good starting spot for you. I think they have a complete sample app called WinHooks or SysHooks... something like that.

Ben · Answer

Doesn't anybody know how to do this?