For VBScript Jocks

[fejjwy]

I'm a VB programmer that needs to call various VB commands dynamically from a database (to avoid hardcoding into a huge Select statement), and the only way I could find to do this is with the ScriptControl, to which you can pass a string and it will execute the line. One of the commands I need to execute is the 'keybd_event' API call that I have declared normally in my local project in a bas file. Here's the declare, no problem so far.

Public Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)

Running keybd_event directly in my code works fine, with the following syntax where ParamVal is the KeyCode to be sent to the program.

keybd_event CByte(ParamVal), 15, 0, 0

I want to store it as a string in a database and then call it with the ScriptControl when necessary. According to MS documentation at msdn.microsoft.com, there's two ways to do this: the Run method and the ExecuteStatement method.

Both require declaration of a reference to the ScriptControl in the project after adding it as a component. Let's use:

Dim x as new ScriptControl

The differenct between the Run and ExecuteMethodStatements is the location of the procedure to be executed. To use Run the code has to be added to the ScriptControl's memory with the AddCode method. ExecuteStatement, on the other hand, executes a procedure that is local to the application in which the ScriptControl is declared so you don't have to use AddCode. Neither method seems to work, though.

The problem with Run is that I can't get the AddCode method to declare the API. It stumbles on the "user32" portion and no syntax I've tried will get past the error. I've tried ""user32"" and chr(34) & chr(34) on both sides of "user32". So I can't seem to set up an API declaration within the ScriptControl.

ExecuteStatement should work according to the documentation but it cannot seem to recognize 'keybd_event' within the following simle Sub that sends a KeyDown event:

Sub KbEventDown(ParamVal As Variant)
keybd_event CByte(ParamVal), 15, 0, 0
End Sub

The syntax I used that fails to make the call is:

X.ExecuteStatement "KbEventDown(" & ParamVal & ")"

At runtime, sending a 't' to the program evaluates to:

"KbEventDown(84)"

and results in the following error:

Microsoft VBScript runtime error: Type mismatch: 'KbEventDown'

Anybody know what's wrong here? Is it no possible to run an API call through VBScript?

[monte96]

No. It's not.

To call windows APIs you have to create a COM wrapper that the ASP page can create an object of and call it's methods. In the class for the COM object create methods that wrap the API calls and do the API calls from the COM object. It is a security thing in IIS and it's actually a good thing it doesn't allow it. (Imagine API calls on the server that are malformed.. boom server is down and windows is crashed.) Presumably with a COM object, the object is sufficiently tested and the API calls working before it is installed and registered on the server.