propertyinfo实例错误“object does not match target type”c上的setvalue#

在以前的项目中,在不同的地方使用带有此代码的copy方法(处理具有相同命名属性但不从公共基类派生或实现公共接口的对象)。

新的工作地点,新的代码库-现在它在setvalue上失败了,“对象与目标类型不匹配”,即使是在非常简单的例子上…上周就成功了……

    public static void Copy(object fromObj, object toObj)
    {   
        Type fromObjectType = fromObj.GetType();
        Type toObjectType = toObj.GetType();

        foreach (System.Reflection.PropertyInfo fromProperty in 
            fromObjectType.GetProperties())
        {
            if (fromProperty.CanRead)
            {
                string propertyName = fromProperty.Name;
                Type propertyType = fromProperty.PropertyType;

                System.Reflection.PropertyInfo toProperty = 
                    toObjectType.GetProperty(propertyName);

                Type toPropertyType = toProperty.PropertyType;

                if (toProperty != null && toProperty.CanWrite)
                {
                    object fromValue = fromProperty.GetValue(fromObj,null);
                    toProperty.SetValue(toProperty,fromValue,null);
                }
            }
        }
    }

    private class test
    {
        private int val;
        private string desc;

        public int Val { get { return val; } set { val = value; } }

        public string Desc { get { return desc; } set { desc = value; } }

    }

    private void TestIt()
    {
        test testo = new test();
        testo.Val = 2;
        testo.Desc = "TWO";

        test g = new test();

        Copy(testo,g);

    }

希望有人能指出我的愚蠢之处????