【标题】：Partial Class
【关键字】：Partial,Class
【来源】：http://blog.csdn.net/lyamlf_net/archive/2007/01/29/1497191.aspx

Partial Class

转自：http://blog.joycode.com/zhanbos/archive/2004/05/25/22402.aspx

ASP.NET 2.0和Avalon都使用了Partial Class. 这样用户的代码和工具生成的代码可以共同组成一个Class.对Partial Type的支持来自编译器. 4个要点如下:

我们把partial 叫做modifier而不是关键字.
同一类型在不同文件里面都需要使用partial
可以只在一个文件,两个文件,或者更多文件中使用partial
Base class只需要声明一次;若多次声明必需完全一致.

例子:
Contact1.cs
using System;
namespace Realize.Net.Potential.Sample1
...{
  public partial class Contact
  ...{
    public Contact(string firstName, string lastName)
    ...{
      this.firstName = firstName;
      this.lastName = lastName;
    }

    int partial = 0;
    private void PartialIsNotAKeyword()
    ...{
      partial++;
    }
  }

  public partial class AdvancedContact: Contact
  ...{
    public AdvancedContact(string firstName, string lastName, string address) : base(firstName, lastName)
    ...{
      this.address = address;
    }
  }
}
Contact2.cs
using System;
namespace Realize.Net.Potential.Sample1
...{
  public partial class Contact
  ...{
    string firstName;
    string lastName;
  }
}
Contact3.cs
using System;
namespace Realize.Net.Potential.Sample1
...{
  public partial class Contact
  ...{
    public virtual string Name
    ...{
      get ...{ return firstName + " " + lastName; }
    }
  }

  public partial class AdvancedContact
  ...{
    string address;
    public override string Name
    ...{
      get
      ...{
        return base.Name + " at " + address;
      }
    }
  }
}
MainFun.cs
using System;
namespace Realize.Net.Potential.Sample1
...{
  public class MainFunc
  ...{
    [STAThread]
    static int Main (string[] args)
    ...{
      Contact contact = new Contact("Zhanbo", "Sun");
      Console.WriteLine(contact.Name);
      AdvancedContact advContact = new AdvancedContact("Zhanbo", "Sun", " 1 Microsoft Way ");
      Console.WriteLine(advContact.Name);
      return 0;
    }
  }
}

To Compile:
csc /out:MySample1.exe /t:exe *.cs

深入了解Generics, iterators, anonymous methods, and partial classes的最佳读本就是更新的C#2.0Specification.