Adding an unmanaged DLL

[adamsmithhrs]

Hello,

wondering if somone could clear something up for me as i have been reading around this subject for a while and am still confused.

I have a DLL from a hardware vendor but i dont know what language the DLL is written in.

I would like to use this DLL from managed code (c#). From what i have read i need this to be a COM object, but i dont really understand how you differentiate between a dll written in C++ which is a COM object and on that isnt.

Each time i try to add the dll as a reference (VS 2003 .Net 2.0) i get the following message:

A reference to MYDLL.dll could not be added. This is not a valid assembly or COM component.

I have tried using PINVOKE see code below and managed to call a method from the DLL using my c# application but i dont really want to write a method for each method the DLL supports, mainly becuase i am worried about casting data types etc

[DllImport("MyDLL.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern bool AlarmLogSize(int lpDirectoryName,
out uint lpFreeBytesAvailable);

Form1.AlarmLogSize(0, out freeBytesAvail);
MessageBox.Show(freeBytesAvail.ToString());

Can anyone tell me how best i can use this DLL and what my options are.

Also i have an example application written in VB6 which come with the DLL and that has a Module which seems looks like this:

Public Declare Function AlarmLogSize Lib "VertX.dll" (ByVal mode As Long, _
logSize As Long) As Long

I have no idea when it comes to VB but i presume this is the equivilent of what am doing with my PINVOKE applicaiton.

Any help really appreicated!

Thanks

Adam

 

[phinoppix]

The error message and the sample from the sdk simply shows your DLL is a win32 dll, not a COM. So with plain C#, you have to use pinvoke to import the functions.

And you're presumption is correct. That VB code is the equivalent of your C# extern method.