Professional Visual Basic Interoperability - Com and Vb6 to .Net

by Hollis, Billy; Lhotka, Rockford

• ISBN13: 9781861005656
• ISBN10: 1861005652
• Format: Trade Paper
• Copyright: 2001-02-01
• Publisher: Springer-Verlag New York Inc

Summary

Covers COM interoperability in detail, and broadens the focus to examine a range of issues that must be handled in order for VB6 and COM code to run on .NET. Aimed at experienced Visual Basic developers who need to make COM and VB6 code interoperate with the new .NET platform. Softcover.

Table of Contents

Introduction	1	(1)
Who is this Book for?	1	(1)
What's Covered in this Book?	1	(1)
What Do I Need to Use this Book?	2	(1)
Conventions	3	(1)
Customer Support	3	(4)
How to Download the Sample Code for the Book	4	(1)
Errata	4	(1)
E-mail Support	4	(1)
p2p.wrox.com	5	(1)
Why this System Offers the Best Support	5	(2)
The Importance of Interoperability	7	(12)
Going Forward with Visual Basic .NET	8	(1)
Two Strategies - Migration and Interoperability	8	(1)
The Migration Option	8	(5)
Major Areas of Incompatibility Between VB6 and Visual Basic .NET	9	(1)
Changes in Data Types	9	(1)
Changes Related to Object-Oriented Programming	10	(1)
Radically Different Means for Creating a Web Interface	11	(1)
Functionality Moved from Keywords to the Underlying Framework	11	(1)
Removal of Obsolete Syntax	11	(1)
Good Candidates for Migration to Visual Basic .NET	12	(1)
Bad Candidates for Migration	12	(1)
Impossible Migration	12	(1)
Implications for Interoperability	13	(1)
Design Situations that Need Interoperability	13	(2)
Web Services	13	(1)
Smart Clients	14	(1)
New ASP .NET Front Ends	14	(1)
Extending Old Components	15	(1)
Distributed Processing of Data	15	(1)
Major Areas of Interoperability	15	(2)
Calling COM Components from .NET	16	(1)
Calling .NET Components from COM	16	(1)
Sharing Data Access Between Old Code and New	16	(1)
Sharing Configuration Information	17	(1)
Calling Non-COM DLLs with Static Entry Points	17	(1)
Wrapping Up	17	(2)
Using COM Components from .NET	19	(58)
COM Component Creation	20	(12)
Building a COM Component	20	(1)
Creating the Project	20	(1)
Project Properties	21	(1)
Class Properties	22	(1)
Sub, Function, and Property Methods	23	(2)
Events	25	(1)
Passing Data	25	(5)
Modules	30	(1)
Binary Compatibility	31	(1)
Importing COM Components	32	(17)
Importing During Design	32	(1)
Visual Studio .NET	33	(3)
Type Library Importer	36	(3)
Primary Interop Assemblies	39	(5)
Handling Dependencies	44	(4)
Importing Dynamically	48	(1)
CreateObject Function	48	(1)
.NET System Class Library Support	48	(1)
Using COM Components	49	(26)
Early Binding	49	(1)
Calling Simple Methods	50	(2)
Using Complex Data Types	52	(1)
Handling Events	53	(1)
Late Binding	54	(1)
Late Binding with a Wrapper Assembly	55	(1)
Late Binding with Dynamic Creation	56	(1)
Manual Invocation of Methods	57	(1)
Object Lifetimes	58	(3)
Multiple Interfaces	61	(2)
Design-Time References	63	(1)
Late Binding	64	(1)
Inheritance	64	(2)
Inspecting a COM Component from .NET	66	(1)
ildasm.exe	66	(3)
Object Browser	69	(2)
Class View	71	(2)
Reflection/Type Object	73	(2)
Summary	75	(2)
Using .NET Assemblies from COM	77	(50)
.NET Assembly Creation	78	(22)
Building a .NET Assembly	78	(1)
Creating the Project	78	(1)
Controlling Object Creation	79	(2)
Adding Methods to the Class	81	(2)
Events	83	(1)
Passing Data	84	(1)
Structures	85	(2)
Enumerated Types	87	(1)
ByVal and ByRef	88	(1)
Setting up for Interop	89	(1)
Using the <ComClass()> Attribute	90	(1)
Applying the <ComClass()> Attribute	90	(1)
Defining the CLSID	90	(2)
Hiding Elements	92	(1)
Exposing the Class Manually	92	(1)
Understanding Interfaces and Classes	93	(7)
Registering .NET Assemblies with COM	100	(7)
Using Visual Studio .NET	101	(1)
Providing a Strong Name	102	(1)
Using Command-Line Utilities	103	(1)
Building the Assembly	104	(1)
Registering the Assembly Directly	105	(1)
Inserting the Assembly into the GAC	106	(1)
Generating the Type Library Only	107	(1)
Using .NET Objects from COM and Windows	107	(18)
Early Binding	108	(1)
Referencing the Assembly	109	(1)
Creating an Instance of the Class	109	(1)
Calling Methods and Properties	110	(2)
Handling Events	112	(1)
Late Binding	113	(1)
Creating an Instance of the Class	113	(1)
Specialized Types Unavailable	114	(1)
Events Unavailable	115	(1)
Dealing with Locked Files	115	(1)
Object Lifetimes	115	(1)
Implementing a Dispose Method	116	(1)
Using the Dispose Method	117	(1)
Multiple and Default Interfaces	117	(1)
Implementing a Secondary Interface	118	(2)
Changing the Default Interface	120	(1)
Inspecting a .NET Assembly from COM	121	(1)
The Object Browser	121	(1)
Using the TypeLib Information Component	122	(3)
Summary	125	(2)
Calling COM Components in MTS and COM+ from .NET	127	(60)
Using COM+ Components	128	(32)
Creating a COM+ Component	129	(1)
Creating the Project	129	(1)
Creating the Class	130	(2)
Taking Advantage of COM+ Transactions	132	(4)
Binary Compatibility	136	(1)
Putting the DLL into COM+	137	(5)
Calling COM+ Components from Visual Basic .NET	142	(1)
Creating the Project	143	(5)
Running the Project	148	(2)
Queued Components	150	(1)
Creating a Queued Component in VB6	151	(6)
Calling the Queued Component from Visual Basic .NET	157	(3)
Transferring Data	160	(14)
Using ADO Recordset Objects	161	(4)
Using Variant Arrays	165	(3)
Using XML Documents	168	(6)
Calling .NET Components in COM+ from VB6	174	(10)
Creating a COM+ Component in .NET	175	(1)
Setting Up the Project	176	(2)
Building a Class	178	(3)
Registering the Assembly with COM+	181	(1)
Making the Class Available to COM Clients	182	(1)
Adding <ComClass()>	183	(1)
Viewing the Interface	183	(1)
Summary	184	(3)
Visual Basic .NET and COM in COM+	187	(28)
COM+ and VB6	188	(1)
Creating an ActiveX DLL for COM+	188	(5)
Registering the DLL in COM+	193	(3)
Creating a VB6 Test Application	196	(1)
COM+ and Visual Basic .NET	197	(5)
Registering the DLL in COM+	202	(2)
Creating a Visual Basic .NET Test Application	204	(2)
Calling VB6 Components from Visual Basic .NET in COM+	206	(3)
Calling Visual Basic .NET Components from VB6 in COM+	209	(3)
Summary	212	(3)
Custom Marshalling	215	(48)
The Four Different Methods of Marshaling	216	(6)
Type I Marshaling: Using Tibimp.exe	216	(2)
Type II Marshaling (Simple Data Type Marshaling): Adding Attributes to the Interface to Use a Standard Type	218	(1)
Type III Marshaling: Marshaling into a Custom Data Structure to be Passed Between COM and .NET	219	(1)
Type IV Marshaling: Implementing the ICustomMarshaler Interface	220	(2)
Performance Issues	222	(1)
Type II Marshaling	222	(12)
Ildasm	222	(1)
Ilasm	223	(1)
Using Ildasm or Ilasm with Type II Marshaling	224	(1)
Create the VB6 COM Component	225	(1)
Use Tlbimp to Create the Runtime-Callable Wrapper	226	(1)
Use Ildasm to Create the Intermediate Language Code	226	(1)
Modify the IL to use Booleans Instead of Integers	226	(5)
Create the New Runtime-Callable Wrapper	231	(1)
Make a New Managed Project to Use Our Modified RCW	231	(2)
Run the Example	233	(1)
Type III Marshaling	234	(13)
A Type III Example	235	(1)
Make the COM Object	236	(1)
Create the Runtime Callable Wrapper	237	(1)
Make a New Managed Project	237	(2)
Modify the Runtime-Callable Wrapper to Return a Usable Type	239	(3)
Finish the Managed Interface	242	(5)
Type IV Marshaling	247	(12)
How it Works	247	(1)
The ICustomMarshaler Interface	248	(1)
Create an Unmanaged COM Component	248	(3)
Create the Managed Person Class and the Custom Marshaler	251	(4)
Modify the Marshal Attributes on the Runtime-Callable Wrapper	255	(2)
Create an Interface to Test the Marshaler	257	(2)
Managed Code to Unmanaged Code	259	(1)
Summary	260	(3)
Threading Issues	263	(24)
Threading Basics	264	(5)
Threading Complexity	265	(1)
Using Single versus Multi-Threading	266	(1)
Threading in VB6	267	(2)
Threading in Visual Basic .NET	269	(1)
Threading Interop	269	(14)
Calling COM from .NET	270	(1)
Calling Multiple COM Components from .NET	270	(2)
Calling VB6 Components from a Multi-Threaded .NET Application	272	(9)
Calling ActiveX EXE Components from Visual Basic .NET	281	(1)
Calling VB6 Components from ASP.NET	282	(1)
Calling .NET from COM	283	(1)
Summary	283	(4)
DCOM, Remoting, and Web Services	287	(32)
XML Web Services	287	(1)
.NET Remoting	288	(1)
DCOM	289	(1)
XML Web Services and Interop	290	(12)
Calling COM from .NET	290	(1)
Creating the Web Service in VB6	290	(5)
Creating the .NET Client	295	(2)
Calling .NET from COM	297	(1)
Creating the XML Web Service	298	(2)
Creating the VB6 Client	300	(2)
.NET Remoting and Interop	302	(14)
Calling COM from .NET	303	(1)
Creating the Wrapper Project	304	(1)
Hosting the Wrapper Assembly for Remoting	305	(4)
Creating a Remoting Client	309	(3)
Calling .NET from COM	312	(1)
Creating the .NET Proxy	313	(2)
Creating the VB6 Client	315	(1)
Summary	316	(3)
Sharing Configuration Information	319	(18)
Private INI Files	320	(6)
The Structure of an INI File	320	(1)
Accessing INI Files in VB6	321	(3)
Accessing INI Files in Visual Basic .NET	324	(2)
Using the Windows Registry to Store Configuration Settings	326	(2)
XML-Based Configuration Files	328	(7)
Accessing XML Configuration Info with the .NET Framework Classes	329	(1)
Accessing Settings Using System.XML in Visual Basic .NET	330	(2)
Accessing Settings Using MSXML in VB6	332	(3)
Concurrency Problems	335	(1)
Summary	335	(2)
Flat File Access in .NET	337	(20)
Random Access to Flat Files	338	(7)
Random Access in VB6	338	(2)
Using FreeFile to Get the File Number	340	(1)
Random Access in Visual Basic .NET	341	(1)
Replacements for File Access Keywords	341	(2)
Structures Replace UDTs in Visual Basic .NET	343	(1)
Handling Fixed Length Strings in Visual Basic .NET	344	(1)
Putting It All Together	344	(1)
Binary Acces to Flat Files	345	(5)
Binary Acess in VB6	345	(3)
Binary Access in Visual Basic .NET	348	(2)
Sequential File Access	350	(2)
Sequential Access in VB6	350	(1)
Sequential Access in Visual Basic .NET	351	(1)
Streams as an Alternative in Visual Basic .NET	352	(3)
Sequential Access with Streaming Techniques	353	(1)
Binary Access with Streaming Techniques	354	(1)
Summary	355	(2)
Using ADO in .NET	357	(12)
Comparison Between ADO and ADO.NET	357	(4)
ADO Advantages and Disadvantages	358	(1)
When is ADO Still Needed in .NET?	359	(1)
ADO.NET Only Has Optimistic Concurrency	359	(1)
ADO Supports Pessimistic Concurrency	359	(1)
ADO.NET Does Not Support Most Cursors	360	(1)
ADO Supports a Variety of Cursors, Including Server.Side	360	(1)
Using ADO in .NET	361	(5)
ADO Code in Visual Basic .NET	362	(1)
Data Binding Limitations	362	(1)
Problems in Setting Some ADO Properties to Strings	363	(1)
Converting an ADO Recordset into an ADO.NET DataSet	364	(2)
DAO and RDO Implications	366	(1)
Summary	367	(2)
Calling API or Static DLL Functions from .NET	369	(16)
Reduced Need for Using DLLs with Static Entry Points in .NET	370	(3)
Reduced Need for Access to Windows API	370	(3)
Retirement of Order Code	373	(1)
Platform Invocation Services	373	(7)
Declaring the API	373	(1)
Calling the API Function	374	(1)
Aliasing a Function	375	(1)
Passing Structures as parameters	375	(2)
Example of an API with a Structure Parameter	377	(1)
Data Marshaling Issues	378	(1)
Dealing with Strings	378	(1)
Using Automatic ANSI/Unicode Location	379	(1)
Getting More Control	380	(1)
Control Over Data Marshaling	380	(1)
Using DLLImport Instead of Declare	380	(1)
Performance Considerations	381	(1)
Summary	382	(3)
Interoperability of ActiveX Controls in .NET	385	(10)
When to Use ActiveX Controls in .NET	386	(1)
The Differences Between Windows Forms Controls and ActiveX Controls	387	(1)
Comparison of Properties	387	(1)
Hosting an ActiveX Control in .NET	387	(5)
Example - Windows Media Player Control	388	(2)
Notes on the Example	390	(1)
Custom Property Moved from Properties List	390	(1)
Creating a Wrapper with Aximp.exe	390	(1)
Importing VB6 UserControls	391	(1)
Controls that Cannot be Imported	391	(1)
Security	391	(1)
.NET Windows Forms Controls in VB6	392	(1)
Summary	392	(3)
How Do I Prepare VB6 Code for Migration?	395	(9)
Stop Using Default Properties and Methods	396	(1)
Avoid Non-Zero Lower Bounds for Arrays	396	(1)
Make All Parameters Explicitly ByRef or ByVal	397	(1)
Place Default Values on All Optional Parameters	397	(1)
Declare All Variables on a Seprate Line	398	(1)
Be Careful Where You Declare Variables	398	(1)
Avoid Fixed Length Strings in UDTs	399	(1)
Get Rid of Obsolete Keywords	400	(1)
Remove Implicit Object Instantiation	400	(1)
Stop Implicit Loading of Forms	401	(1)
Switch Data Binding to ADO	402	(1)
Use Intrinsic Constants Whenever Possible	402	(1)
Stop Writing DHTML Pages and WebClasses	403	(1)
Wrap Your API Calls	403	(1)
Get Your Logic Out of the UI and Into Components and Classes	404	(1)
Avoid Late Binding	404	(1)
Summary	404