请教一个动态定义变量问题~

Question

不能直接使用属性,需用InvokeMember来实现

Answer 1

using System;
using System.Reflection;// This sample class has a field, constructor, method, and property.
class MyType 
{
    Int32 myField;
    public MyType(ref Int32 x) {x *= 5;}
    public override String ToString() {return myField.ToString();}
    public Int32 MyProp 
    {
        get {return myField;}
        set 
        { 
            if (value < 1) 
                throw new ArgumentOutOfRangeException("value", value, "value must be > 0");
            myField = value;
        }
    }
}class MyApp 
{
    static void Main() 
    {
        Type t = typeof(MyType);
        // Create an instance of a type.
        Object[] args = new Object[] {8};
        Console.WriteLine("The value of x before the constructor is called is {0}.", args[0]);
        Object obj = t.InvokeMember(null, 
            BindingFlags.DeclaredOnly | 
            BindingFlags.Public | BindingFlags.NonPublic | 
            BindingFlags.Instance | BindingFlags.CreateInstance, null, null, args);
        Console.WriteLine("Type: " + obj.GetType().ToString());
        Console.WriteLine("The value of x after the constructor returns is {0}.", args[0]);        // Read and write to a field.
        t.InvokeMember("myField", 
            BindingFlags.DeclaredOnly | 
            BindingFlags.Public | BindingFlags.NonPublic | 
            BindingFlags.Instance | BindingFlags.SetField, null, obj, new Object[] {5});
        Int32 v = (Int32) t.InvokeMember("myField", 
            BindingFlags.DeclaredOnly | 
            BindingFlags.Public | BindingFlags.NonPublic | 
            BindingFlags.Instance | BindingFlags.GetField, null, obj, null);
        Console.WriteLine("myField: " + v);        // Call a method.
        String s = (String) t.InvokeMember("ToString", 
            BindingFlags.DeclaredOnly | 
            BindingFlags.Public | BindingFlags.NonPublic | 
            BindingFlags.Instance | BindingFlags.InvokeMethod, null, obj, null);
        Console.WriteLine("ToString: " + s);        // Read and write a property.
        try 
        {
            t.InvokeMember("MyProp", 
                BindingFlags.DeclaredOnly | 
                BindingFlags.Public | BindingFlags.NonPublic | 
                BindingFlags.Instance | BindingFlags.SetProperty, null, obj, new Object[] {0});
        } 
        catch (TargetInvocationException e) 
        {
            if (e.InnerException.GetType() != 
                typeof(ArgumentOutOfRangeException)) 
                throw;
            Console.WriteLine("Catch the property set.");
        }
        t.InvokeMember("MyProp", 
            BindingFlags.DeclaredOnly | 
            BindingFlags.Public | BindingFlags.NonPublic | 
            BindingFlags.Instance | BindingFlags.SetProperty, null, obj, new Object[] {2});
        v = (Int32) t.InvokeMember("MyProp", 
            BindingFlags.DeclaredOnly | 
            BindingFlags.Public | BindingFlags.NonPublic | 
            BindingFlags.Instance | BindingFlags.GetProperty, null, obj, null);
        Console.WriteLine("MyProp: " + v);
    }
}

Answer 2

用反射即可实现.
ms-help://MS.VSCC/MS.MSDNVS.2052/cpref/html/frlrfSystemTypeClassGetMembersTopic1.htm
ms-help://MS.VSCC/MS.MSDNVS.2052/cpref/html/frlrfSystemTypeClassGetPropertiesTopic1.htm