COM Interop question in .NET 2.0

[Vish]

Hi,

I am trying to expose my .NET 2.0 class as a COM type using the following
attributes for the attributes

[ClassInterface( ClassInterfaceT ype.None)]
[Guid("8D0240AD-1BBE-4831-8214-39DD46A4A797")]

I have the "Register for COM Interop" build property set to true. I also
have two functions in the class to register and unregister the COM with the
registry. But when i try to build it in VS.NET 2005, i get the following
error "XXX.dll does not contain any types that can be registered for COM
Interop" and "XXX.dll does not contain any types that can be Unregistered for
COM Interop". The same code works perfectly in VS.NET 2003. Anybody know of
any reasons why this is happeneing or what i am doing wrong?

Thank You,
Vish

[Erik]

Thank you for your answer, but I'm afraid that didn't help. Now the
code looks like this:

using System;
using System.Collecti ons.Generic;
using System.Text;

namespace Com_test
{
public class Class1
{
public Class1() { }
}
}

but it still cannot be registered for COM interop.

[Willy Denoyette [MVP]]

"Erik" <er************ *@bredband.net> wrote in message
news:11******** **************@ o13g2000cwo.goo glegroups.com.. .

Thank you for your answer, but I'm afraid that didn't help. Now the
code looks like this:

using System;
using System.Collecti ons.Generic;
using System.Text;

namespace Com_test
{
public class Class1
{
public Class1() { }
}
}

but it still cannot be registered for COM interop.

It should, what error are you getting?

The simplest way to test this is compile the file from the command line
using:

csc /t:library filename.cs
and register with:
regasm /codebase /tlb filename.dll
unregister with:
regasm /unregister /tlb filename.dll

Willy.

[Willy Denoyette [MVP]]

You said you couldn't register, now you are teling me you could't compile!
A C# class needs to obey a number of rules (imposed by COM), one of the is
a default public construcor, but there are others.
A public constructor is in general all you need to be able to create an
instance, that doesn't mean that methods are callable. As I said your class
can be instantiated, but your methods are not callable from a native COM
client itself, the fact it works in your case is because you methods
OnCreate and OnClick are not called from COM, they are called from the
container (they are event handlers right?) .
Willy.

"Vish" <Vi**@discussio ns.microsoft.co m> wrote in message
news:0F******** *************** ***********@mic rosoft.com...

Hi Willy,

Since the class i had created did have a constructor explicitly defined,
why
do you think i wasn't able to compile my class in 2.0

Thank You,
Vish
"Willy Denoyette [MVP]" wrote:

"Erik" <er************ *@bredband.net> wrote in message
news:11******** *************@g 47g2000cwa.goog legroups.com...

> In my experiment i created an empty class library, resulting in the
> following code.
>
> using System;
> using System.Collecti ons.Generic;
> using System.Text;
>
> namespace Com_test
> {
> public class Class1
> {
> }
> }
>
> Shouldn't it compile without an error, even with "Register for COM
> interop" checked?
>

This class will compile but cannot be registered for COM interop as it
doesn't have an explicit public empty constructor .

this ...
public class Class1
{
public Class1(){}
}

will do.

Willy.

[Vish]

Hi Willy,

Yes, i wasnt able to compile. I am sorry if i had misrepresentd in
previously. Also my OnCreate and OnClick functions are in fact getting called
by event handlers. Can you let me know where i can read up on the rules my c#
class needs to foolow in order to be callable from COM.

Thank You,
Vish
"Willy Denoyette [MVP]" wrote:

"Erik" <er************ *@bredband.net> wrote in message
news:11******** **************@ o13g2000cwo.goo glegroups.com.. .

Thank you for your answer, but I'm afraid that didn't help. Now the
code looks like this:

using System;
using System.Collecti ons.Generic;
using System.Text;

namespace Com_test
{
public class Class1
{
public Class1() { }
}
}

but it still cannot be registered for COM interop.

It should, what error are you getting?

The simplest way to test this is compile the file from the command line
using:

csc /t:library filename.cs
and register with:
regasm /codebase /tlb filename.dll
unregister with:
regasm /unregister /tlb filename.dll

Willy.

[Mark Harris]

I hate dredging this up as its so old, but thought i'd clear this up. After
spending the past 3 days trying everything possible to get my C# code to work
in COM, i almost gave up until seeing this post.

To put it bluntly, the documentation is wrong.

The code i was using in 1.1 DID NOT WORK in 2.0. Simple test case below:

---------- BEGIN ITVTest.cs ----------
using System;
using System.Text;
using System.Runtime. InteropServices ;

namespace comitvtest
{
[Guid("3A8E1A9D-206E-48cb-BD4F-0FE6D3155CDF")]
[ClassInterface( ClassInterfaceT ype.AutoDual)]
[ComVisible(true )]
public class ITVTest : IITVTest
{
public ITVTest()
{
throw new System.NotImple mentedException ();
}

public int GetCurrentHour( )
{
return System.DateTime .Now.Hour;
}
}
}

---------- END ITVTest.cs ----------
---------- BEGIN IITVTest.cs ----------
using System;
using System.Runtime. InteropServices ;
namespace comitvtest
{
[Guid("770A5441-1B1D-4847-91B5-B84EDDC1B647")]
interface IITVTest
{
int GetCurrentHour( );
}
}
---------- END IITVTest.cs ----------
--- Project Setup ---
Goto Project -> Properties
Click the "Build" tab.
Select the Register for COM Interop option

Click the "Signing" tab.
Select "Sign the Assembly", from the file name select "<new>" give it a name
i used KeyPairing.snk with NO password
Build project
start -> run: cmd

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

H:\>c:

C:\>cd projects\com.it v.test

C:\Projects\com .itv.test\bin\R elease>tlbexp com.itv.test.dl l
Microsoft (R) .NET Framework Assembly to Type Library Converter 2.0.50727.42
Copyright (C) Microsoft Corporation. All rights reserved.

Assembly exported to 'C:\Projects\co m.itv.test\bin\ Release\com.itv .test.tlb'

C:\Projects\com .itv.test\bin\R elease>regasm com.itv.test.dl l
/tlb:com.itv.tes t.t
lb
Microsoft (R) .NET Framework Assembly Registration Utility 2.0.50727.42
Copyright (C) Microsoft Corporation 1998-2004. All rights reserved.

Assembly exported to
'C:\Projects\co m.itv.test\bin\ Release\com.itv .test.tlb', an
d the type library was registered successfully

--- Visual Basic 6 Test ---
Create new Standard EXE project
Goto to Project menu, select References
Find the com assembly in references list (com_itv_test), select, and hit OK
View the object browser
Types are visible here. (can also do the same with with Visual FoxPro's
Class Explorer and open the TLB file.)
--- The Proof ---
Now try it without the ComVisible attribute.
- Mark Harris

C:\Projects\com .itv.test>cd bin/release
"Willy Denoyette [MVP]" wrote:

Sorry, but this is not a complete sample (missing BaseCommand), so there is
lttle I can do with it, but trust me [ComVisible(true )] IS the default.

I'm also not entirely clear on the purpose is of this class for a COM
client, true, this object creatable from COM clients, but none of it's
methods are callable.
Willy.

"Vish" <Vi**@discussio ns.microsoft.co m> wrote in message
news:EB******** *************** ***********@mic rosoft.com...

Hi,

Ok. I am not sure why but it did fix the issue. Obviously y'all know more
on
this subject than i do. But i am posting my code below if y'all are still
interested.

[ClassInterface( ClassInterfaceT ype.None)]
[Guid("8D0240AD-1BBE-4831-8214-39DD46A4A797")]
[ComVisible(true )]
public sealed class TestTool : BaseCommand
{
private IApplication m_app;

public override void OnCreate(object hook)
{
if (hook != null)
{
if (hook is IMxApplication)
{
m_app = (IApplication)h ook;
}
}
}

public override void OnClick()
{
IMxDocument mxDoc = (IMxDocument)m_ app.Document;
IActiveView activeView = mxDoc.ActiveVie w;
activeView.Exte nt = activeView.Full Extent;
activeView.Refr esh();
}

public TestTool()
{
base.m_category = "Vish's Test";
base.m_caption = "Full Extent C#";
base.m_message = "Zooms the display to its full extent";
base.m_toolTip = "Full Extent C#";
base.m_name = "Developer Samples_FullExt ent C#";

string[] res = GetType().Assem bly.GetManifest ResourceNames() ;
if (res.GetLength( 0) > 0)
{
base.m_bitmap = new
System.Drawing. Bitmap(GetType( ).Assembly.GetM anifestResource Stream(res[0]));
}
}

#region Component Category Registration

[ComRegisterFunc tion()]
[ComVisible(fals e)]
static void RegisterFunctio n(String regKey)
{
MxCommands.Regi ster(regKey);
}

[ComUnregisterFu nction()]
[ComVisible(fals e)]
static void UnregisterFunct ion(String regKey)
{
MxCommands.Unre gister(regKey);
}

#endregion
}






"Willy Denoyette [MVP]" wrote:

"Jason Newell" <no****@nospam. com> wrote in message
news:eC******** ******@TK2MSFTN GP11.phx.gbl...
> Yeah I know it's always been default because it's bitten me in the
> rear-end a few times ;-). I honestly didn't think that they would have
> made a breaking change like that. So the question that still remains,
> did
> setting [ComVisible(true )] really solve the problem or was it something
> else?
>
>
> Jason Newell
>
>

Pretty sure it was something else (my guess: missing public on the
class).

Willy.

[Willy Denoyette [MVP]]

The default ComVisible attribute value did not change, what did change in
VS2005 was the AssemblyInfo.cs file which now contains [assembly:
ComVisible(fals e)]. But, the default (that is whan the attribute is not
specified) is still true.
Willy.

"Mark Harris" <Mark Ha****@discussi ons.microsoft.c om> wrote in message
news:DB******** *************** ***********@mic rosoft.com...
|I hate dredging this up as its so old, but thought i'd clear this up. After
| spending the past 3 days trying everything possible to get my C# code to
work
| in COM, i almost gave up until seeing this post.
|
| To put it bluntly, the documentation is wrong.
|
| The code i was using in 1.1 DID NOT WORK in 2.0. Simple test case below:
|
| ---------- BEGIN ITVTest.cs ----------
| using System;
| using System.Text;
| using System.Runtime. InteropServices ;
|
| namespace comitvtest
| {
| [Guid("3A8E1A9D-206E-48cb-BD4F-0FE6D3155CDF")]
| [ClassInterface( ClassInterfaceT ype.AutoDual)]
| [ComVisible(true )]
| public class ITVTest : IITVTest
| {
| public ITVTest()
| {
| throw new System.NotImple mentedException ();
| }
|
| public int GetCurrentHour( )
| {
| return System.DateTime .Now.Hour;
| }
| }
| }
|
| ---------- END ITVTest.cs ----------
|
|
| ---------- BEGIN IITVTest.cs ----------
| using System;
| using System.Runtime. InteropServices ;
| namespace comitvtest
| {
| [Guid("770A5441-1B1D-4847-91B5-B84EDDC1B647")]
| interface IITVTest
| {
| int GetCurrentHour( );
| }
| }
| ---------- END IITVTest.cs ----------
|
|
| --- Project Setup ---
| Goto Project -> Properties
| Click the "Build" tab.
| Select the Register for COM Interop option
|
| Click the "Signing" tab.
| Select "Sign the Assembly", from the file name select "<new>" give it a
name
| i used KeyPairing.snk with NO password
|
|
| Build project
| start -> run: cmd
|
| Microsoft Windows XP [Version 5.1.2600]
| (C) Copyright 1985-2001 Microsoft Corp.
|
| H:\>c:
|
| C:\>cd projects\com.it v.test
|
| C:\Projects\com .itv.test\bin\R elease>tlbexp com.itv.test.dl l
| Microsoft (R) .NET Framework Assembly to Type Library Converter
2.0.50727.42
| Copyright (C) Microsoft Corporation. All rights reserved.
|
| Assembly exported to
'C:\Projects\co m.itv.test\bin\ Release\com.itv .test.tlb'
|
| C:\Projects\com .itv.test\bin\R elease>regasm com.itv.test.dl l
| /tlb:com.itv.tes t.t
| lb
| Microsoft (R) .NET Framework Assembly Registration Utility 2.0.50727.42
| Copyright (C) Microsoft Corporation 1998-2004. All rights reserved.
|
| Assembly exported to
| 'C:\Projects\co m.itv.test\bin\ Release\com.itv .test.tlb', an
| d the type library was registered successfully
|
| --- Visual Basic 6 Test ---
| Create new Standard EXE project
| Goto to Project menu, select References
| Find the com assembly in references list (com_itv_test), select, and hit
OK
| View the object browser
| Types are visible here. (can also do the same with with Visual FoxPro's
| Class Explorer and open the TLB file.)
|
|
| --- The Proof ---
| Now try it without the ComVisible attribute.
|
|
| - Mark Harris
|
|
|
| C:\Projects\com .itv.test>cd bin/release
| "Willy Denoyette [MVP]" wrote:
|
| > Sorry, but this is not a complete sample (missing BaseCommand), so there
is
| > lttle I can do with it, but trust me [ComVisible(true )] IS the default.
| >
| > I'm also not entirely clear on the purpose is of this class for a COM
| > client, true, this object creatable from COM clients, but none of it's
| > methods are callable.
| >
| >
| > Willy.
| >
| > "Vish" <Vi**@discussio ns.microsoft.co m> wrote in message
| > news:EB******** *************** ***********@mic rosoft.com...
| > > Hi,
| > >
| > > Ok. I am not sure why but it did fix the issue. Obviously y'all know
more
| > > on
| > > this subject than i do. But i am posting my code below if y'all are
still
| > > interested.
| > >
| > > [ClassInterface( ClassInterfaceT ype.None)]
| > > [Guid("8D0240AD-1BBE-4831-8214-39DD46A4A797")]
| > > [ComVisible(true )]
| > > public sealed class TestTool : BaseCommand
| > > {
| > > private IApplication m_app;
| > >
| > > public override void OnCreate(object hook)
| > > {
| > > if (hook != null)
| > > {
| > > if (hook is IMxApplication)
| > > {
| > > m_app = (IApplication)h ook;
| > > }
| > > }
| > > }
| > >
| > > public override void OnClick()
| > > {
| > > IMxDocument mxDoc = (IMxDocument)m_ app.Document;
| > > IActiveView activeView = mxDoc.ActiveVie w;
| > > activeView.Exte nt = activeView.Full Extent;
| > > activeView.Refr esh();
| > > }
| > >
| > > public TestTool()
| > > {
| > > base.m_category = "Vish's Test";
| > > base.m_caption = "Full Extent C#";
| > > base.m_message = "Zooms the display to its full extent";
| > > base.m_toolTip = "Full Extent C#";
| > > base.m_name = "Developer Samples_FullExt ent C#";
| > >
| > > string[] res =
GetType().Assem bly.GetManifest ResourceNames() ;
| > > if (res.GetLength( 0) > 0)
| > > {
| > > base.m_bitmap = new
| > >
System.Drawing. Bitmap(GetType( ).Assembly.GetM anifestResource Stream(res[0]));
| > > }
| > > }
| > >
| > > #region Component Category Registration
| > >
| > > [ComRegisterFunc tion()]
| > > [ComVisible(fals e)]
| > > static void RegisterFunctio n(String regKey)
| > > {
| > > MxCommands.Regi ster(regKey);
| > > }
| > >
| > > [ComUnregisterFu nction()]
| > > [ComVisible(fals e)]
| > > static void UnregisterFunct ion(String regKey)
| > > {
| > > MxCommands.Unre gister(regKey);
| > > }
| > >
| > > #endregion
| > > }
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > >
| > > "Willy Denoyette [MVP]" wrote:
| > >
| > >>
| > >> "Jason Newell" <no****@nospam. com> wrote in message
| > >> news:eC******** ******@TK2MSFTN GP11.phx.gbl...
| > >> > Yeah I know it's always been default because it's bitten me in the
| > >> > rear-end a few times ;-). I honestly didn't think that they would
have
| > >> > made a breaking change like that. So the question that still
remains,
| > >> > did
| > >> > setting [ComVisible(true )] really solve the problem or was it
something
| > >> > else?
| > >> >
| > >> >
| > >> > Jason Newell
| > >> >
| > >> >
| > >>
| > >> Pretty sure it was something else (my guess: missing public on the
| > >> class).
| > >>
| > >> Willy.
| > >>
| > >>
| > >>
| > >>
| > >>
| >
| >
| >

[Sara Carnell]

Jason, if you could e-mail me at my e-mail address that would be
wonderful.
Sara

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