CHAPTER 2 BUILDING C# APPLICATIONS
Referencing Multiple External Assemblies
On a related note, what if you need to reference numerous external assemblies using csc.exe? Simply list
each assembly using a semicolon-delimited list. You don’t need to specify multiple external assemblies
for the current example, but some sample usage follows:
csc /r:System.Windows.Forms.dll;System.Drawing.dll *.cs
Note As explained a bit later in this chapter, the C# compiler will automatically reference a set of core .NET
assemblies (such as System.Windows.Forms.dll), even if they are not specified using the /r flag.
Compiling Multiple Source Files
The current incarnation of the TestApp.exe application was created using a single *.cs source code file.
While it is perfectly permissible to have all of your .NET types defined in a single *.cs file, most projects
are composed of multiple *.cs files to keep your code base a bit more flexible. Assume you have
authored a new class contained in a new file named HelloMsg.cs.
// The HelloMessage class
using System;
using System.Windows.Forms;
class HelloMessage
{
public