. Operator (C# Reference)
Visual Studio 2010
The dot operator (.) is used for member access. The dot operator specifies a member of a type or namespace. For example, the dot operator is used to access specific methods within the .NET Framework class libraries:
// The class Console in namespace System: System.Console.WriteLine("hello");
For example, consider the following class:
class Simple { public int a; public void b() { } }
Simple s = new Simple();
The variable s has two members, a and b; to access them, use the dot operator:
s.a = 6; // assign to field a; s.b(); // invoke member function b;
The dot is also used to form qualified names, which are names that specify the namespace or interface, for example, to which they belong.
// The class Console in namespace System: System.Console.WriteLine("hello");
The using directive makes some name qualification optional:
namespace ExampleNS { using System; class C { void M() { System.Console.WriteLine("hello"); Console.WriteLine("hello"); // Same as previous line. } } }
But when an identifier is ambiguous, it must be qualified:
namespace Example2 { class Console { public static void WriteLine(string s){} } } namespace Example1 { using System; using Example2; class C { void M() { // Console.WriteLine("hello"); // Compiler error. Ambiguous reference. System.Console.WriteLine("hello"); //OK Example2.Console.WriteLine("hello"); //OK } } }
For more information, see the C# Language Specification. The language specification is the definitive source for C# syntax and usage.
