Calling WinAPI Functions from .NET

[Guest]

Are there any concise rules about when you need to marshal data to WinAPI
calls, and when you don't? It appears that most times you can call WinAPI
calls directly from .NET without any preparation. For example

Declare Function OpenPrinter Lib "winspool.drv" Alias "OpenPrinterA" (ByVal
pPrinterName As String, ByVal phPrinter As Integer,
<MarshalAs(UnmanagedType.Struct)> ByRef pDefault As PRINTER_DEFAULTS) As
Integer

Dim tmpHandle As Int32
Dim msDeviceName as String = "MyPrinter"
OpenPrinter(msDeviceName, tmpHandle, 0)

However, some functions appear to require all kinds of fancy manipulation
before you get to call them--particularly ones which require structures or
arrays. (See http://www.codeproject.com/vb/net/printwatchvbnet.asp). Why
isn't .NET smart enough to handle this "under the covers", the way that VB6
is?

 

[Peter Foot [MVP]]

There are a couple of articles on MSDN which describe the capabilities /
limitations of Platform Invocation (P/Invoke) from .NETCF:-
http://msdn.microsoft.com/smartclie...ary/en-us/dnnetcomp/html/netcfintrointerp.asp
http://msdn.microsoft.com/smartclie...rary/en-us/dnnetcomp/html/netcfadvinterop.asp

Peter

 

[Alex Feinman [MVP]]

Right, but the question was targeting the full framework I think...
I would say, read this:
http://www.amazon.com/exec/obidos/t...bs_b_2_1/102-7923610-2368922?v=glance&s=books