Question

为什么以下Delegate.CreateDelegate会产生运行时ArgumentException？

static class Module1
{
    public static void Main()
    {
        MyDataObject mdo = new MyDataObject();
        mdo.DoMagic("Hello");
    }

    #region Assembly A
    public class BusinessObject
    {
    }

    public class MyBusinessObject : BusinessObject
    {

        public void DoMagic(string s)
        {
            Console.WriteLine(s);
        }
    }
    #endregion

    #region Assembly B
    public class MyDataObject
    {
        private delegate void DoMagicDel(BusinessObject bo, string s);

        private DoMagicDel delDoMagic;
        public void DoMagic(string s)
        {
            BusinessObject bo = (BusinessObject)Activator.CreateInstance(Type.GetType("Module1+MyBusinessObject"));
            MethodInfo mi = bo.GetType().GetMethod("DoMagic", BindingFlags.Public | BindingFlags.Instance);
            // ArgumentException: Cannot bind to the target method because its signature or security transparency is not compatible with that of the delegate type.
            delDoMagic = (DoMagicDel)Delegate.CreateDelegate(typeof(DoMagicDel), null, mi);
            delDoMagic(bo, s);
        }
    }
    #endregion
}

如果程序集A具有对程序集B的项目引用，反之则不然。当我将第一个参数DoMagicMel更改为MyBusinessObject类型时，它可以工作。但是因为程序集B不知道这种类型的程序集A，所以这只适用于我的简化示例：

private delegate void DoMagicDel(MyBusinessObject bo, string s);

有机会让这个工作吗？

Answer 1

ArgumentException: Cannot bind to the target method because its signature or security transparency is not compatible with that of the delegate type.

为什么以下Delegate.CreateDelegate会生成运行时ArgumentException？

因为DoMagicDel的签名与mi描述的方法的签名不符。

有机会让这个工作吗？

是的，使用MakeGenericType来匹配mi的签名：

#region Assembly B
public class MyDataObject
{
    public delegate void DoMagicDel<T1>(T1 arg1, string arg2);
    private static Delegate delDoMagic;
    public void DoMagic(string s)
    {
        var bo = Activator.CreateInstance("Module1", "Module1.MyBusinessObject").Unwrap();
        MethodInfo mi = bo.GetType().GetMethod("DoMagic", BindingFlags.Public | BindingFlags.Instance);
        var doMagicDelType = typeof(DoMagicDel<>).MakeGenericType(bo.GetType());            
        if (delDoMagic == null)
            delDoMagic = Delegate.CreateDelegate(doMagicDelType, null, mi);
        delDoMagic.DynamicInvoke(bo, s);
    }
}
#endregion

我希望我不会太迟......

通过反射创建打开的实例委托

1 个答案: