tests/test-394.cs

   1 // Compiler options: -langversion:default
   2 //
   3 // Test for contravariance support in delegates
   4 //
   5
   6 using System;
   7
   8  public class A {
   9          protected string name;
  10
  11          public A (string name)
  12          {
  13                  this.name = "A::" + name;
  14          }
  15
  16          public A ()
  17          {
  18          }
  19
  20          public string Name {
  21                  get {
  22                          return name;
  23                  }
  24          }
  25  }
  26
  27  public class B : A {
  28          public B (string name)
  29          {
  30                  this.name = "B::" + name;
  31          }
  32
  33          public B ()
  34          {
  35          }
  36  }
  37
  38  public class C : B {
  39          string value;
  40
  41          public C (string name, string value)
  42          {
  43                  this.name = "C::" + name;
  44                  this.value = value;
  45          }
  46
  47          public string Value {
  48                  get {
  49                          return value;
  50                  }
  51          }
  52  }
  53
  54  public class Tester {
  55
  56          delegate string MethodHandler (C c);
  57
  58          static string MethodSampleA (A value)
  59          {
  60                  return value.Name;
  61          }
  62
  63          static string MethodSampleB (B value)
  64          {
  65                  return value.Name;
  66          }
  67
  68          static string MethodSampleC (C value)
  69          {
  70                  return value.Name + " " + value.Value;
  71          }
  72
  73          static void Main ()
  74          {
  75                  MethodHandler da = MethodSampleA;
  76                  MethodHandler db = MethodSampleB;
  77                  MethodHandler dc = MethodSampleC;
  78
  79                  C a = new C ("Hello", "hello");
  80                  C b = new C ("World", "world");
  81                  C c = new C ("!", "!!!");
  82
  83                  Console.WriteLine (da (a));
  84                  Console.WriteLine (db (b));
  85                  Console.WriteLine (dc (c));
  86          }
  87
  88  }
  89