c# - 如何设置 targetPi？我认为定义不正确，但我不知道如何解决这个问题？

Question

//这里有一些代码

    object target = Activator.CreateInstance(typeof(T));   

    PropertyInfo[] sourceProperties = sourceType.GetProperties();

    foreach (PropertyInfo pi in sourceProperties)
    {
         PropertyInfo targetPi = typeof(T).GetProperty(pi.Name); //returns null why?

         object piValue = pi.GetValue(source, null);

         try
         {
               if (targetPi != null)   // it doesnt work 
               {
                    targetPi.SetValue(target,piValue, null); // target has typeof(T)
               }
         }
         catch { }         
    }
    return(T)target;
}

Answer 1

这对我有用：

struct Item1 { public double Foo { get; set; } }
struct Item2 { public double Foo { get; set; } }

class Program
{
    static void Main(string[] args)
    {
        Item1 i1 = new Item1();
        CopyDynamically(new Item2 { Foo = 42 }, ref i1);

        Console.WriteLine(i1.Foo);


        i1 = CopyDynamically<Item1>(new Item2 { Foo = 3.14 });

        Console.WriteLine(i1.Foo);
    }

    static void CopyDynamically<T>(object source, ref T target)
    {
        if (source == null)
            throw new ArgumentNullException("source");
        if (target == null)
            throw new ArgumentNullException("target");

        foreach (PropertyInfo pi in source.GetType().GetProperties())
        {
            PropertyInfo targetPi = typeof(T).GetProperty(pi.Name);

            if (targetPi != null && targetPi.SetMethod != null && targetPi.SetMethod.IsPublic)
            {
                object val = pi.GetValue(source, null);
                object o = target;

                try { targetPi.SetValue(o, val, null); }
                catch { }

                target = (T)o;
            }
        }
    }
    static T CopyDynamically<T>(object source, params object[] ctorArgs)
    {
        T target = (T)Activator.CreateInstance(typeof(T), ctorArgs);

        CopyDynamically(source, ref target);

        return target;
    }
}