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Attribute.GetHashCode メソッド

定義

このインスタンスのハッシュ コードを返します。

public override int GetHashCode ();

戻り値

32 ビット符号付き整数ハッシュ コード。

次のコード例は、 のコンテキストAttributeでの のGetHashCode使用を示しています。

using System;
using System.Reflection;
using System.Collections.Generic;

// A custom attribute to allow two authors per method.
public class AuthorsAttribute : Attribute
{
   protected string _authorName1;
   protected string _authorName2;

   public AuthorsAttribute(string name1, string name2)
   {
      _authorName1 = name1;
      _authorName2 = name2;
   }

   public string AuthorName1
   {
      get { return _authorName1; }
      set { _authorName1 = value; }
   }

   public string AuthorName2
   {
      get { return _authorName2; }
      set { _authorName2 = value; }
   }

   // Use the hash code of the string objects and xor them together.
   public override int GetHashCode()
   {
      return _authorName1.GetHashCode() ^ _authorName2.GetHashCode();
   }
}

// Provide the author names for each method of the class.
public class TestClass
{
  [Authors("Immanuel Kant", "Lao Tzu")]
  public void Method1()
  {}

  [Authors("Jean-Paul Sartre", "Friedrich Nietzsche")]
  public void Method2()
  {}

  [Authors("Immanuel Kant", "Lao Tzu")]
  public void Method3()
  {}

  [Authors("Jean-Paul Sartre", "Friedrich Nietzsche")]
  public void Method4()
  {}

  [Authors("Immanuel Kant", "Friedrich Nietzsche")]
  public void Method5()
  {}
}

class Example
{
   static void Main()
   {
      // Get the class type to access its metadata.
      Type clsType = typeof(TestClass);

      // Store author information in a list of tuples.
      var authorsInfo = new List<Tuple<String, AuthorsAttribute>>();

      // Iterate through all the methods of the class.
      foreach(var method in clsType.GetMethods())
      {
          // Get the Authors attribute for the method if it exists.
          AuthorsAttribute authAttr =
              (AuthorsAttribute)Attribute.GetCustomAttribute(
              method, typeof(AuthorsAttribute));
          if (authAttr != null)
             // Add the information to the author list.
             authorsInfo.Add(Tuple.Create(clsType.Name + "." + method.Name,
                                             authAttr));
      }

      // Iterate through the list
      bool[] listed = new bool[authorsInfo.Count];
      Console.WriteLine("Method authors:\n");

      for (int ctr = 0; ctr < authorsInfo.Count; ctr++) {
         var authorInfo = authorsInfo[ctr];
         if (!listed[ctr]) {
             Console.WriteLine("{0} and {1}", authorInfo.Item2.AuthorName1,
                                              authorInfo.Item2.AuthorName2);
             listed[ctr] = true;
             Console.WriteLine("   {0}", authorInfo.Item1);
             for (int ctr2 = ctr + 1; ctr2 < authorsInfo.Count; ctr2++) {
                 if (!listed[ctr2])
                    if (authorInfo.Item2.Equals(authorsInfo[ctr2].Item2)) {
                       Console.WriteLine("   {0}", authorsInfo[ctr2].Item1);
                       listed[ctr2] = true;
                    }
            }
         }
      }
   }
}
// The example displays the following output:
//       Method authors:
//
//       Immanuel Kant and Lao Tzu
//          TestClass.Method1
//          TestClass.Method3
//       Jean-Paul Sartre and Friedrich Nietzsche
//          TestClass.Method2
//          TestClass.Method4
//       Immanuel Kant and Friedrich Nietzsche
//          TestClass.Method5

適用対象

製品 バージョン
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP 10.0