C#のリフレクションについて、思いつくままにコードを書く

C#のリフレクションについて、いくつかの簡単なプログラムを書いてみる。

ReflectionTestクラスのフィールド情報を取得する。

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

class ReflectionTest
{
    public Int32 i = 0;
    public String s = String.Empty;
    public Double d = 0.0;
    public override String ToString()
    {
        return String.Format("i = {0}, s = {1}, d = {2}", i, s, d);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Type t = typeof(ReflectionTest);
        foreach (FieldInfo fi in t.GetFields())
        {
            Console.WriteLine("Name:{0}, Type:{1}, Public:{2}, Static:{3}, MetadataToken:{4}",
                fi.Name, fi.FieldType, fi.IsPublic, fi.IsStatic, fi.MetadataToken);
        }
    }
}

実行結果

Name:i, Type:System.Int32, Public:True, Static:False, MetadataToken:67108865
Name:s, Type:System.String, Public:True, Static:False, MetadataToken:67108866
Name:d, Type:System.Double, Public:True, Static:False, MetadataToken:67108867

---

ReflectionTestクラスのインスタンスに値をセットする

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

class ReflectionTest
{
    public Int32 i = 0;
    public String s = String.Empty;
    public Double d = 0.0;
    public override String ToString()
    {
        return String.Format("i = {0}, s = {1}, d = {2}", i, s, d);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Type t = typeof(ReflectionTest);
        Object o = Activator.CreateInstance(typeof(ReflectionTest));
        foreach (FieldInfo fi in t.GetFields())
        {
            if (fi.Name == "i")
            {
                //Int32型のフィールド i に 100 をセット
                fi.SetValue(o, 100);
            }
            else if (fi.Name == "s")
            {
                //String型のフィールド s に "String" をセット
                fi.SetValue(o, "String");
            }
            else if (fi.Name == "d")
            {
                //Double型のフィールド d に 11.11 をセット
                fi.SetValue(o, 11.11);
            }
        }
        ReflectionTest reflectionTest = (ReflectionTest)o;
        Console.WriteLine(reflectionTest);
    }
}

実行結果

i = 100, s = String, d = 11.11

---

ReflectionTestクラスのメソッド情報を取得する

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

class ReflectionTest
{
    public Int32 i = 0;
    public String s = String.Empty;
    public Double d = 0.0;
    public void MethodA()
    {
        Console.WriteLine("This is MethodA");
    }
    public override String ToString()
    {
        return String.Format("i = {0}, s = {1}, d = {2}", i, s, d);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Type t = typeof(ReflectionTest);
        foreach (MethodInfo mi in t.GetMethods())
        {
            Console.WriteLine("Name = {0}, Public = {1}, DeclaringType = {2}", 
                mi.Name, mi.IsPublic, mi.DeclaringType);
        }
    }
}

実行結果

Name = MethodA, Public = True, DeclaringType = ReflectionTest
Name = ToString, Public = True, DeclaringType = ReflectionTest
Name = GetType, Public = True, DeclaringType = System.Object
Name = Equals, Public = True, DeclaringType = System.Object
Name = GetHashCode, Public = True, DeclaringType = System.Object

---

Stringを１つ引数にもつメソッドを呼び出す

class ReflectionTest
{
    public Int32 i = 0;
    public String s = String.Empty;
    public Double d = 0.0;
    public void MethodA(String s)
    {
        Console.WriteLine("This is MethodA:{0}", s);
    }
    public void MethodB(String s)
    {
        Console.WriteLine("This is MethodB:{0}", s);
    }

    public override String ToString()
    {
        return String.Format("i = {0}, s = {1}, d = {2}", i, s, d);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Object o = Activator.CreateInstance(typeof(ReflectionTest));
        Type t = typeof(ReflectionTest);
        foreach (MethodInfo mi in t.GetMethods())
        {
            ParameterInfo[] parameters = mi.GetParameters();

            //引数が１つでかつ、型がStringのメソッドを呼び出す
            if (parameters.Length == 1 && parameters[0].ParameterType == typeof(String))
            {
                mi.Invoke(o, new Object[1] { String.Format("{0} is called", mi.Name) });
            }
        }
    }
}

実行結果

This is MethodA:MethodA is called
This is MethodB:MethodB is called