相关疑难解决方法(0)

为什么以下代码不起作用:

class Program
{
    static void Main ( string[ ] args )
    {
        SomeClass s = new SomeClass( );

        s.GetType( ).GetField( "id" , System.Reflection.BindingFlags.NonPublic ) // sorry reasently updated to GetField from GetProperty...
            .SetValue( s , "new value" );
    }
}


class SomeClass
{
    object id;

    public object Id 
    {
        get
        {
            return id;
        }
    }   
}

我试图设置私有字段的值.

这是我得到的例外:

System.NullReferenceException未处理Message = Object引用未设置为对象的实例.来源= ConsoleApplication7
StackTrace:位于C:\ Users\Antonio\Desktop\ConsoleApplication7\ConsoleApplication7\Program.cs中的Program.Main(String [] args):位于System的System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly,String [] args)的第18行. System.Threading.ExecutionContext.Run上的System.Threading.ThreadHelper.ThreadStart_Context(Object state)中的Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()中的AppDomain.ExecuteAssembly(String assemblyFile,Evidence assemblySecurity,String [] args)(ExecutionContext executionContext System.Threading.ThreadHelper.ThreadStart()中的System.Threading.ExecutionContext.Run(ExecutionContext executionContext,ContextCallback回调,对象状态),ContextExallback回调,对象状态,布尔值ignoreSyncCtx:InnerException:

TypedReference在实际代码中实际使用的结构是否有任何实际用途？

编辑:.Net框架在重载中使用它们,Console.WriteLine并String.Concat从__arglist参数构建数组并将其传递给正常的params重载.为什么存在这些过载？

我正在尝试使用反射(最终在编译时未知)object,包括struct.我已经到了,TypedReference.MakeTypedReference但我已经撞墙了.

这是我的班级和结构

public class MyObject
{
    public int Id;
    public Money Amount; 
}

public struct Money
{
    public int Vaule;
    public string Code;
}

这是我如何尝试使用反射在MyObject中设置"数量"的"代码".正如我上面提到的,我正在寻找一种在编译时不了解这些类型的解决方案(这太容易了!)

这是我到目前为止的代码(我使用[0],[1]来使代码更简单)

var obj = new MyObject() { Id = 1 };
obj.Amount.Vaule = 10;
obj.Amount.Code = "ABC";

FieldInfo[] objFields = obj.GetType().GetFields();
FieldInfo[] moneyFields = objFields[1].GetValue(obj).GetType().GetFields();

List<FieldInfo> fields = new List<FieldInfo>() { objFields[1] };
fields.AddRange( moneyFields );

TypedReference typeRef = TypedReference.MakeTypedReference( 
                           objFields[1].GetValue( obj ), fields.ToArray() );

moneyFields[1].SetValueDirect( typeRef, "XXX" ); …

   class PriceClass {

        private int value;
        public int Value
        {
            get { return this.value; }
            set { this.value = value; }
        }           
    }


    struct PriceStruct
    {

        private int value;
        public int Value
        {
            get { return this.value; }
            set { this.value = value; }
        }
    }
    static void Main(string[] args)
    {
        PriceClass _priceClass = new PriceClass();
        Type type = typeof(PriceClass);
        PropertyInfo info = type.GetProperty("Value");
        info.SetValue(_priceClass, 32, null);
        Console.WriteLine(_priceClass.Value);

        PriceStruct _priceStruct = new PriceStruct();
        type = typeof(PriceStruct);
        info = type.GetProperty("Value");
        info.SetValue(_priceStruct, …

我正在编写自己的方法将对象图转换为自定义对象,因为JavaScriptSerializer会在空值上触发错误.

所以这就是我到目前为止所做的:

internal static T ParseObjectGraph<T>(Dictionary<string, object> oGraph)
{
    T generic = (T)Activator.CreateInstance<T>();
    Type resType = typeof(T);
    foreach (PropertyInfo pi in resType.GetProperties())
    {
        object outObj = new object();
        if (oGraph.TryGetValue(pi.Name.ToLower(), out outObj))
        {
            Type outType = outObj.GetType();
            if (outType == pi.PropertyType)
            {                        
                pi.SetValue(generic, outObj, null);
            }
        }
    }
    return generic;
}

现在该pi.SetValue()方法运行,并且不会触发错误,但是当我查看属性时generic,它仍然与之前的相同.

它经历的第一个属性是布尔值,因此值最终会像这样

generic = an object of type MyCustomType
generic.property = false
outObj = true
pi = boolean property
outType = boolean

然后在SetValue方法运行后, …