PB COM DLL from C#

[Niall Hallett]

Hi,

I've just started with PB and have been tasked with creating a com dll to be used in a c# project. To begin with I've used the following example to create a com dll:

#COMPILE DLL
#COM TLIB ON

#RESOURCE "MyClass.pbr"

#DIM ALL

#COM NAME "MyClass", 1.00
#COM DOC  "Example Class"

$MyClassGuid = GUID$("{00000099-0000-0000-0000-000000000008}")
$MyIfaceGuid = GUID$("{00000099-0000-0000-0000-000000000009}")

'------------------------------------------------------------------------------------------------------------------------------------------------------
CLASS MyClass $MyClassGuid AS COM
    INSTANCE Counter AS LONG

    INTERFACE MyInterface $MyIfaceGuid
        INHERIT DUAL            ' inherit the base class

        METHOD BumpIt(Inc AS LONG) AS LONG
            LOCAL Temp AS LONG
            Temp& = Counter + Inc
            INCR Counter
            METHOD = Temp&
        END METHOD

    END INTERFACE

END CLASS

This successfully compiles, the type library is embedded and the dll is registered.

If I create a simple PB client to access this class it works. However, from Visual Studio, the following c# code:

using System;
using MyClass;

namespace simplecom
{
    public class Class1
    {
        public static void Main(String[] Args)
        {
            MyClassClass Stuff = new MyClassClass();

            int value, x, y;

            value = 77;

            x = Stuff.BUMPIT(ref value);
            y = Stuff.BUMPIT(ref value);

            Console.WriteLine("x: {0}, y: {1}", x, y);
        }
    }
}

although it compiles (thanks to 9.01 of PB), when run it generates the following exception:

Unhandled Exception: System.InvalidCastException: Unable to cast COM object of type 'MyClass.MyClassClass' to interface type 'MyClass.MYINTERFACE'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00000099-0000-0000-0000-000000000009}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).
   at MyClass.MyClassClass.BUMPIT(Int32& INC)
   at simplecom.Class1.Main(String[] Args) in z:\Visual Studio 2008\Projects\simplecom\simplecom\Class1.cs:line 16

I'm at a complete loss, it appears not to like the argumentbeing passed to the method.

Cheers,
Niall

[Edwin Knoppert]

>using MyClass;

Afaik you must add a reference in VS.
Using is a namespace and imo does not apply to com objects.

[Niall Hallett]

I did the Project->Add Reference in VS to select my COM server to import the namespace, the C# won't compile otherwise.

[Peter Redei]

I think it is simply a case problem. PB automatically capitalized MyInterface and C# is case sensitive. Try to write the PB method with capitalized letters and see what happens.


Peter Redei

[Niall Hallett]

I set the method to all uppercase in PB, but I still get the same runtime error from VS.

[Michael Mattias]

Try to write the PB method with capitalized letters and see what happens.

Perhaps a use for...

[CLASS|OVERRIDE] METHOD name [<DispID>] [B][COLOR="Red"][ALIAS "altname"] [/COLOR][/B](var AS type...) [AS type]

Unfortunately the help file page never explains or demonstrates the use of ALIAS. I shall send in a "Documentation Improvement Suggestion"

MCM

[Niall Hallett]

I've also tried using random GUIDs from the PBWin IDE and changed the name of the class from the confusing MyClass.

Still getting the same runtime error in VS.

Has anyone actually managed to get COM Objects written in PB to work from C#?

[Edwin Knoppert]

Yes.
I forgot but it is simple.
Embed the tlb file in the dll.

[Edwin Knoppert]

My PwrDev object dll template works just fine:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            PwrDev_COM_server.CLASS1 c = new PwrDev_COM_server.CLASS1();
            String T = c.DateValue;
        }
    }
}

Class:

'----------------------------------------------------
' Class
' CLASS name  [$GUID]  [AS COM | AS EVENT]
' Use like:
'    Local oInterface1 As Interface1
'    oInterface1 = Class "Class1"
'----------------------------------------------------

Class Class1 Guid$("{3BB832AC-D358-4A79-A82C-FF53AEABE2A1}") As Com

    '----------------------------------------------------
    ' Class private data.
    '----------------------------------------------------

    Instance mDateValue As String

    '----------------------------------------------------
    ' Class methods.
    '----------------------------------------------------

    ' Class constructor, initialize class here.
    Class Method Create
        mDateValue = UCode$( Time$ )
    End Method

    ' Class destructor, clean up.
    Class Method Destroy

    End Method

    Class Method ClassMethod1( ByVal Param As Long ) As String
        Method = Format$( Param )
    End Method

    '----------------------------------------------------
    ' Interfaces.
    ' (INTERFACE interfacename [$GUID] [AS EVENT] [AS COM])
    '----------------------------------------------------

    Interface Interface1 Guid$("{19DF21F0-3118-453C-8A62-CF72D176A807}"): Inherit Dual

        Property Get DateValue Alias "DateValue"() As String
            Property = mDateValue
        End Property

        Property Set DateValue Alias "DateValue"( ByVal DateValue As String )
            mDateValue = DateValue
        End Property

        Method SetDateValue Alias "SetDateValue"( ByVal DateValue As String )
            mDateValue = DateValue
        End Method

        Method MyClassMethod Alias "MyClassMethod"( ByVal Param As Long ) As String
            Method = Me.ClassMethod1( Param )
        End Method

    End Interface

End Class

(and the app guids of course)

[Niall Hallett]

I compiled your example PB and tried a simple VS C# test:

using System;
using edwin;

namespace simplecom
{
    public class NewClass
    {
        public static void Main(String[] Args)
        {
            CLASS1 c = new CLASS1();

            String T = c.DateValue;
        }
    }
}

but still get the same runtime error:

System.InvalidCastException was unhandled
  Message="Unable to cast COM object of type 'edwin.CLASS1Class' to interface type 'edwin.INTERFACE1'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{19DF21F0-3118-453C-8A62-CF72D176A807}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE))."
  Source="Interop.edwin"
  StackTrace:
       at edwin.CLASS1Class.get_DateValue()
       at simplecom.NewClass.Main(String[] Args) in z:\Visual Studio 2008\Projects\simplecom\simplecom\Class1.cs:line 12
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

[Edwin Knoppert]

1) Is there a com name specified?
2) For convienance, did you insert the tlb into the dll?
3) Why using.. again? it has nothing to do with the namespaces (imo).
4) Add reference done?
5) dll registered?

Pfffftt

[Niall Hallett]

1) Is there a com name specified?

if you mean #COM NAME then yes.

2) For convienance, did you insert the tlb into the dll?

yep.

3) Why using.. again? it has nothing to do with the namespaces (imo).

why does it matter, you either:

use module

to import the name or state each declaration tediously:

module.CLASS c = new module.CLASS();

I tried it your way and it makes no difference to the error.

4) Add reference done?

I have added a reference to the project. It wouldn't compile otherwise.

5) dll registered?

I wouldn't be able to add a reference if I hadn't done this.

Pfffftt

Yep.

[Edwin Knoppert]

Using is for namespaces, imo not related to com interfaces and .NET class without namespace.

I can help you.. remote (teamviewer.com) or send the dll.

[Niall Hallett]

We have just discovered that if you create a new project in VS and use the Windows Forms Application instead of the Console Application like I was originally, then it actually works!

So, the problem appears to be with VS Console App projects.

[Scott Slater]

You should really use

 
 
private void Form1_Shown(object sender, EventArgs e)
{
 
}

instead of Form1_Load, because it doesn't execute when the form is first loaded. Place a MessageBox.Show("Hello"); there to see if it is executing.

I am also getting the exception when trying to load a PB COM LIB from C#.

[Scott Slater]

So, the problem appears to be with VS Console App projects.

Have you verified this? I can't get C# to call PB "COM" at all. As stated earlier, the Form1_Load doesn't execute right away, so you won't see an error by placing the code there. I don't get any error until I actually try creating the object reference elsewhere in the C# code. I have tried various types of base classes in PB too, all with the same result as Niall was experiencing.

I would like to see a working example of calling a PB method from a C# program with working results.

[Edwin Knoppert]

You must have PB9.01 not 9.00 (or CC)

[Scott Slater]

Yes, using PB 9.01 with VS 2008 C#

[Scott Slater]

PB Win 9.01 Code:

#Compile Dll
#Dim All
#Resource "ExToCSharp.pbr"  ' <--- For embeding TLB
 
$LIBID = Guid$("{21AADD80-14AF-43B3-B829-841E094BAB2C}")
$CLSID = Guid$("{FFD516C6-B12A-4823-861C-8F3B607E7E1F}")
$IID = Guid$("{8C796C42-3442-4E09-8F5C-839B8E450BAF}")
 
#Com Doc "This is a test library created with PowerBASIC for use with C#"
#Com Name "PBTest", 1.00
#Com Guid $LIBID
#Com TLib On
 
%USEMACROS=1
#Include "Win32Api.inc"
 
Class PBClass $CLSID As Com
 
   Instance idVal1 As Dword
   Instance idVal2 As Dword
 
   Class Method Create
      idVal1 = 1
      idVal2 = 2
   End Method
 
   Interface PBInt $IID: Inherit Dual
 
      Property Get Val1 Alias "Val1" As Dword
         Property = idVal1
      End Property
 
      Property Set Val1 Alias "Val1" (ByVal inVal As Dword)
         idVal1 = inVal
      End Property
 
      Property Get Val2 Alias "Val2" As Dword
         Property = idVal2
      End Property
 
      Property Set Val2 Alias "Val2" (ByVal inVal As Dword)
         idVal2 = inVal
      End Property
 
      Method SumVals Alias "SumVals" As Dword
         Method = idVal1 + idVal2
      End Method
 
      Method ResetVals Alias "ResetVals"
         Me.Create
      End Method
 
      Method Num2String Alias "Num2String"(ByVal inVal As Dword) As String
         Method = UCode$(Format$(inVal))
      End Method
 
      Method ClearVals Alias "ClearVals"
         idVal1 = 0: idVal2 = 0
      End Method
   End Interface
 
End Class

Compiles fine, and can be accessed from another PB Client Ap without problems.

C# Code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using PBTest;  // <-- PB Library Name, this works because it shows up in intelesense.
// Works without it too, if you use the long names in the calls below.

// Still throws an exception however when creating the object.

namespace MyTestAp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Shown(object sender, EventArgs e)
        {
            PBCLASS pb = new PBCLASS();  // <---  Fails on this line!
            pb.Val2 = 7;
            MessageBox.Show(pb.Num2String(pb.Val2));
        }
    }
}

The C# app gets an exceptio on the ... new PBCLASS() line.

[Scott Slater]

## update:

## UPDATE:

I found out what was causing the problem in my situation. I am running 64-Bit Vista and my build environment on the C# program was set to "Platform = Any". This was building a 64-Bit version apparently, so I explicitly changed the build platform to equal x86 and it now can see the PB Created Obj Code!!

I just wanted to pass this along since I know someone else will encounter a similar similar problem at some point.