Vb and Vb.Net

Hi Arun,

VB 6 programs require significant modification to run under VB .NET

VB6 was interpreter based language while VB.NET is a compiled language

The greatest change in VB6 and VB.NET is of runtime environment. VB6 used the VB-Runtime while VB .NET adheres to the Common Language Specification (CLS) for language interoperability which is also shared with C#.

VB 4, 5, and 6 were backward compatible VB .NET is not backward compatible

VB6 was not a type-safe language while VB.NET is a type safe language. There is no variant type in VB.NET and no type conversions happen automatically in VB.NET

VB6 used the 'On Error Goto' syntax to handle exceptions at runtime. VB.NET uses the Try…Catch…Finally syntax to handle exceptions at runtime.

Changes to Procedure Calls 

A lot of code (like user interface code) in VB6 was hidden from developer. In VB.NET no code is hidden from developer and you can access and control each part of your application and it now has C-like Syntax 

VB .NET is now has object oriented programming features

Arrays is  0 based in VB .NET. i.e when you declare an array in vb6 "Dim Items(5) As String" you would get an array with 6 elements but in VB.NET it would be 5 items now.

No More Variant, Currency Data Types in VB.NET, you also get the new data types in Visual Basic. NET called Object other changes are as follow.

VB2008.NET	VB6	Difference
Short	Integer	16 Bit
Integer	Long	32 Bit
Long		64 Bit
Object	Variant	Variant Dropped use the new Object Data Type
Decimal
String	String	No Fixed Length String in Vb.NET
	Currency	Use Decimal or long in vb2008

VB6 does not allow developing the multithreaded applications. In VB.NET you can create multithreaded applications.

VB6 was only considered good for desktop windows application. In VB.NET you can develop web applications, distributed applications, create .NET windows and web controls and components, write windows and web services.

In VB.NET, you can also use reflections to read the meta-data of types and using reflection emit you can also generate code to define and invoke types at runtime.

VB.NET uses .NET framework class library along with specialized VB library (System.VisualBasic) as a standard library. As a result, the standard library for VB.NET is much enhanced and useful compared to VB6 standard library

VB.NET is platform independent because of .Net framework. Programs written in VB.NET can run on any platform where .Net framework is present. The platform include both hardware and software (operating system) platforms.

VB.NET also supports language interoperability with various .NET compliant languages. This means that you can use and enhance the code written in other .NET compliant languages. Similarly the code written in VB.NET can also be used and enhanced by other .NET compliant languages. Although VB6 also provided this functionality through COM but it was limited and difficult to use and manage. VB.Net makes it easier because of the presence of Intermediate Language (IL) and Common Language Specification (CLS) of the .NET architecture.

VB6 uses COM (Component Object Model) as component architecture. VB.NET uses assemblies as its component architecture. The Assemblies architecture has removed a lot of problems with COM including DLL-Hell and versioning problem.

Components created in VB6 (COM) need tomake and update registry entries. VB.NET does not require any registryentry making the deployment easier

The CLR Garbage Collector is also more efficient than VB6 one as it may detect cyclic references too.

VB6 used ASP to build web applications. VB.NET uses ASP.NET to build web applications.

VB6 used ADODB and record-sets to implement data access applications. VB.NET uses ADO.NET and datasets to build data access applications. The ADO.NET also supports the disconnected data access. ADO.NET operates better with Web applications

• The greatest change in VB6 and VB.NET is of runtime environment. VB6 used the VB-Runtime while VB.NET uses the .Net Common Language Runtime (.Net CLR). The CLR is much better designed and implemented than VB-Runtime. The CLR uses better code translation through Just in Time compiler while VB-Runtime interprets the code. The CLR Garbage Collector is also more efficient than VB6 one as it may detect cyclic references too.

• VB6 was interpreter based language while VB.NET is a compiled language

• VB6 was not a type-safe language while VB.NET is a type safe language. There is no variant type in VB.NET and no magical type conversions happen in VB.NET

• VB6 used 'On Error Goto' syntax to handle exceptions at runtime. VB.NET uses the Try…Catch…Finally syntax to handle exceptions at runtime.

• A lot of code (like user interface code) in VB6 was hidden from developer. In VB.NET no code is hidden from developer and you can access and control each part of your application

• VB.NET has much enhanced object oriented support than VB6

• VB6 does not allow developing the multithreaded applications. In VB.NET you can create multithreaded applications.

• VB6 was only considered good for desktop windows application. In VB.NET you can also develop web applications, distributed applications, create .NET windows and web controls and components, write windows and web services.

• In VB.NET, you can also use reflections to read the meta-data of types and using reflection emit you can also generate code to define and invoke types at runtime.

• VB.NET uses .NET framework class library along with specialized VB library (System.VisualBasic) as a standard library. As a result, the standard library for VB.NET is much enhanced and useful compared to VB6 standard library

• VB.NET is platform independent because of .Net framework. Programs written in VB.NET can run on any platform where .Net framework is present. The platform include both hardware and software (operating system) platforms.

• VB.NET also supports language interoperability with various .NET compliant languages. This means that you can use and enhance the code written in other .NET compliant languages. Similarly the code written in VB.NET can also be used and enhanced by other .NET compliant languages. Although VB6 also provided this functionality through COM but it was limited and difficult to use and manage. VB.Net makes it easier because of the presence of Intermediate Language (IL) and Common Language Specification (CLS) of the .NET architecture.

• VB6 uses COM (Component Object Model) as component architecture. VB.NET uses assemblies as its component architecture. The Assemblies architecture has removed a lot of problems with COM including DLL-Hell and versioning problem.

• Components created in VB6 (COM) need to make and update registry entries. VB.NET does not require any registry entry making the deployment easier

• VB6 used ASP to build web applications. VB.NET uses ASP.NET to build web applications.

• VB6 used ADODB and record-sets to implement data access applications. VB.NET uses ADO.NET and datasets to build data access applications. The ADO.NET also supports the disconnected data access.

Please refer the below link

http://www.programmersheaven.com/2/FAQ-VBNET-VB6-VBNET-Differences

http://www.vbtutor.in/getting-started-with-visual-basic-net/differences-between-vb-6-and-visual-studio-net


Thanks