How can I call a .NET DLL from an Inno Setup script?

Question

I want to call a function from a .NET DLL (coded in C#) from an Inno Setup script.

I have:

1. marked the Register for COM interop option in the project properties,

2. changed the ComVisible setting in the AssemblyInfo.cs file,

3. added these lines to the ISS script:

   [Files]
   Source: c:\temp\1\MyDLL.dll; Flags: dontcopy
   

   [Code]
   function MyFunction(): string;
       external 'MyFunction@files:MyDLL.dll stdcall setuponly';
   

But I still get the following error:

Runtime Error (at -1:0):

Cannot Import dll:C:\DOCUME~1\foo\LOCALS~1\Temp\is-LRL3E.tmp\MyDLL.dll.

What am I doing wrong?

Answer 1

Intenta de esta manera (Try this way):

Var
 obj: Variant
 va: MyVariableType;
Begin
 //Starting
 ExtractTemporaryFile('MyDll.dll');
 RegisterServer(False, ExpandConstant('{tmp}\MyDll.dll'), False);
 obj := CreateOleObject('MyDll.MyClass');
 //Using
 va := obj.MyFunction();
 //Finishing
 UnregisterServer(False, ExpandConstant('{tmp}\MyDll.dll'), False);
 DeleteFile('{tmp}\MyDll.dll');
End;

Suerte (good luck)

Answer 2

Oops, my bad, it's been too long since I've read pascal! So, if you need to get the value then there are a couple of possibilities:

1. Write the functionality in C/C++ and export the function, that's definitely supported.
2. Use a Managed C++ dll to shim to your .NET dll, and expose the call as a C interface point (this should work, but it's getting messy)
3. Use an .exe to store the result of your code in a .INI file or the registry or in a temp file and read the result in the setup code section (this is now properly nasty)

When I last worked with InnoSetup it didn't support your scenario directly (calling .NET code from setup).

Answer 3

I read a little bit more about it - now I can see the difference between importing a C-style function and creating an OLE object.

Something like this would work for me:

[Code]
procedure MyFunction();
var
  oleObject: Variant;
begin
  oleObject := CreateOleObject('MyDLL.MyDLL');

  MsgBox(oleObject.MyFunction, mbInformation, mb_Ok);
end;

but it requires registering the DLL file.

I guess I will have to create a command-line application to call the functions from the DLL.

Answer 4

Use the Unmanaged Exports library to export a function from a C# assembly, in a way that it can be called in Inno Setup.

• Implement a static method in C# class library
• Add the Unmanaged Exports NuGet package to your project
• Set Platform target of your project to x86
• Add the DllExport attribute to your method
• If needed, define a marshaling for the function arguments (particularly marshaling of string arguments has to be defined).
• Build

using RGiesecke.DllExport;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;

namespace MyNetDll
{
    public class MyFunctions
    {
        [DllExport(CallingConvention = CallingConvention.StdCall)]
        public static bool RegexMatch(
            [MarshalAs(UnmanagedType.LPWStr)]string pattern,
            [MarshalAs(UnmanagedType.LPWStr)]string input)
        {
            return Regex.Match(input, pattern).Success;
        }
    }
}

On Inno Setup side:

[Files]
Source: "MyNetDll.dll"; Flags: dontcopy

[Code]
function RegexMatch(Pattern: string; Input: string): Boolean;
    external 'RegexMatch@files:MyNetDll.dll stdcall';

And now you can use your function like this:

if RegexMatch('[0-9]+', '123456789') then
begin
  Log('Matched');
end
  else
begin
  Log('Not matched');
end;

---

See also:

• Returning a string from a C# DLL with Unmanaged Exports to Inno Setup script
• Inno Setup - External .NET DLL with dependencies

Answer 5

You're trying to import a C-style function from your .NET dll - this doesn't really have anything to do with COM interop. COM interop allows you to activate your .NET objects as COM objects, it doesn't expose them as C/C++ exported functions/types.

If your function doesn't need to return any data, why not make a simple .exe that calls your function and just run that from your setup?

Also: See the innosetup support newsgroups where you might get better support.

Answer 6

Try using delayload, it is used for a dll that may not exist at runtime. This solve the problem.

For example:

[Files]
Source: odbccp32.dll; Flags: dontcopy

[Code]
procedure SQLConfigDataSource(hwndParent: Integer; Frequest: Integer; LpszDriver: String; lpszAttributes: String);
external 'SQLConfigDataSource@files:odbccp32.dll stdcall delayload';

Answer 7

A .NET dll can be best called from any other programming language by exposing it as a COM object. Take a look at this example: http://support.microsoft.com/kb/828736. This shows how to call a ".NET dll" from "unmanaged C++". You can replace the "unamanged C++" by any other programming language, that can be used as a COM client.