interop

I'm trying to delete a worksheet from a excel document from a .Net c# 3.5 application with the interop Excel class (for excel 2003). I try many things like : Worksheet worksheet = (Worksheet)workbook.Worksheets[1]; worksheet.Delete(); It's doesn't work and doesn't throw any error ... Melursus After more than one hour looking I found the answer: xlApp.DisplayAlerts = false; worksheet.Delete(); xlApp.DisplayAlerts = true; itsho When dealing with deleting Excel Worksheets , there are two important things to know: Excel interop counts from 1 (and not from zero), therefore, removing the second item

This question already has an answer here: How do I handle null or optional dll struct parameters in C# 1 answer I have a few p/invoked functions (but I'm rewriting my code at the moment so I'm tidying up) and I want to know how to use/pass a nullable type as one of the parameters. working with int types isn't a problem but given the following: [DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)] static extern IntPtr SetupDiGetClassDevs(ref Guid ClassGuid, int? enumerator, IntPtr hwndParent, uint Flags); I'd like to be able to pass the Guid parameter as a nullable type. As

I have had this problem with C# when I was using DotNet1.1 The problem is this. I have an unmanaged dll, which has a function which takes a function pointer (among other arguments). When I declare the DLLImport in C# code, I pass a delegate. But the delegates in C# have stdcall calling convention whereas the unmanaged function expects a cdecl function pointer. Thus my naive approach resulted in crashes. Then I found the following: http://www.codeproject.com/KB/cs/cdeclcallback.aspx Some guy wrote an excellent library that enables changing calling convention of the delegate by, as I understood,

I'm looking for a way to perform pointer operations in C# or .NET in particular. I want to do something very simple Having a pointer IntPtr I want to get IntPtr object which points to 2 bytes ahead. I read some post that the foolowing snippet will work... IntPtr ptr = new IntPtr(oldptr.ToInt32() + 2); But I have doubts whether this statement is also valid for 64-bit machine (since addressing is in 64-bits there).. I found this elegant method to add offset, but unfortunately is in .NET 4.0 only http://msdn.microsoft.com/en-us/library/system.intptr.add%28VS.100%29.aspx Laurent Etiemble I suggest

Consider the following C# code using a COM object. MyComObject o = new MyComObject; try { var baz = o.Foo.Bar.Baz; try { // do something with baz } finally { Marshal.ReleaseComObject(baz); } } finally { Marshal.ReleaseComObject(o); } This will release the COM objects o and baz , but not the temporary objects returnd by o.Foo and o.Foo.Bar . This can cause problems, when those objects hold a large amount of unmanaged memory or other resources. An obvious but ugly solution would be, to clutter the code even more with try-finally and Marshal.ReleaseComObject . See C# + COM Interop, deterministic

I am writing a C# application which uses Interop services to access functions in a native C++ DLL. I am already using about 10 different functions which are working. Now I am not sure how to handle passing a callback as a parameter so that the DLL can call my code. Here is the function prototype of the DLL: typedef void (WINAPI * lpfnFunc)(const char *arg1, const char *arg2) And the function that allows me to pass the above type: int WINAPI SetFunc(lpfnFunc f) Here is my C# code for the delegate and function definitions: public delegate void Func(string arg1, string arg2); public static void