What is entry point method of VB.NET program?

Bernard Aybout (Virii8)

6 years ago

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Understanding the Main Method in VB.NET

Introduction

In VB.NET, the Main method acts as the central entry point for console applications. This is where the program begins execution. The method must be static, known as Shared in VB.NET, allowing it to be called without creating an instance of the class.

Characteristics of the Main Method

Shared:The Main method is declared Shared, meaning it does not require an instance of the class to be executed. This is essential because it’s the first method called when your application starts.
Access Modifiers:The Main method is typically Public or Friend. Public makes it accessible from any part of the application or from other applications, whereas Friend restricts access to the current assembly, which is useful for internal software mechanisms.
Return Type:The return type can be Sub if no value is returned, or Function if an integer exit code is returned. The exit code is a conventional way to indicate whether the program ended successfully or with an error.

Code Examples

Simple Main Method

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Main Method with Arguments and Exit Code

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Setting Up the Main Method

In projects with multiple classes or modules, you must specify which Main method to use as the startup object. This is done in the project properties within Visual Studio:

Open Project Properties:Right-click on the project in the Solution Explorer and select ‘Properties’.
Change the Startup Object:Go to the ‘Application’ tab.From the ‘Startup object’ dropdown, select the module or class with the Main method you wish to use.

Additional Points

Error Codes:Common exit codes include 0 for successful execution and non-zero values for different error states. Defining these explicitly can help in debugging and managing execution flow in scripts or batch jobs.
Advanced Topics:For more advanced users, exploring asynchronous operations, multi-threading, or integrating with other systems might be the next steps.

Conclusion

Understanding the Main method in VB.NET is crucial for creating standalone applications and scripting tasks. By managing how arguments are handled and defining clear exit strategies, developers can build robust and scalable applications.