code 39 barcode generator vb.net Setting metadata for a multifile assembly in VB.NET

Maker Code 128 Code Set A in VB.NET Setting metadata for a multifile assembly

The statements used to set the assembly metadata for a single-file assembly are interpreted by the C# compiler. When using the assembly linker to create a multifile assembly, the metadata can be specified using command-line switches. The following command illustrates setting metadata via the command line; the switches that were used to set metadata appear in boldface:

3. Creating Assemblies al /out:App.exe /target:exe /main:HelloWorld.Main /title:MyAssembly /description:"This is a multifile assembly" /company:MyCompany /product:MyProduct HelloWorld.netmodule StringPrinter.netmodule

Summary

This chapter has provided a working knowledge of the key tools necessary to build applications for the .NET Framework. We also provided a detailed description of assemblies. Assemblies are one of the most significant differences introduced by the .NET Framework. Assemblies have an impact on almost every aspect of .NET and provide some sophisticated features to aid the packaging and deployment of applications. More advanced information about assemblies, including how to create an assembly that can be shared between applications, can be found in Appendix B.

This chapter details the basic syntax, structure, and features of the C# language. We expect the reader to be familiar with the Java language, and we concentrate on C# features that are new or different.

We begin with a simple program example to demonstrate the basic points that must be understood when writing C# code. The following Java code should be familiar:

public class Hello { public static void main(String[] args) { System.out.println("Hello World!"); } }

Contrast it with the following C# code:

using System; public class Hello { public static void Main(String[] args) { Console.WriteLine("Hello World!"); } }

Although obvious similarities exist, the following points should be noted:

The java.lang package is implicitly imported to all Java programs. C# does not implicitly import any classes. The

using System;

statement makes the classes required for this program available. Note that System in the C# code refers to a namespace from the .NET class libraries, not a specific class as it does in Java. Importing classes into C# programs is covered in the "Using Namespaces" section later in this chapter.

The classes and methods used to write to the console are different. The .NET class libraries are covered in Part III of this book; console output is covered in 10, "Streams, Files, and I/O." The application entry point or main method uses different capitalization; it's Main in C#. See the next section for more information about the Main method.

The capitalization of the method name is not the only difference between the two Main methods. The Java main method has the following signature:

public static void main(String[] args)

The Main method in C# can return either an int or a void and can take either an array of string arguments or nothing as its parameters, resulting in the following four possible signatures:

static static static static void void int int Main() Main(String[] args) Main() Main(String[] args)

Points to note:

The public access modifier is not required for the C# Main method. The application entry point is always accessible to the runtime regardless of its declared accessibility. The int returned by the third and fourth signatures serves as the termination status code that is returned to the execution environment on termination of the program. This is equivalent to the use of Runtime.getRuntime.exit(int) or System.exit(int) in Java. The Main method signatures that return void will always return 0 as the termination status code.

C# implements a code documentation tool similar to the javadoc utility. Like javadoc, this works only if the developer places markup in appropriately formatted code comments. Unlike javadoc, this markup is extracted at compile time and is output to a separate file as XML. Being XML, this information can be easily processed to produce documentation in different formats not just HTML, but any format that is supported by a valid XSL transformation. The most common approach, however, is to utilize an XSL transformation to generate HTML pages. Code documentation comments are preceded by three forward slashes, as shown here: