KB: c#之反射

有时为了使相似度较高的代码智能化，我们会使用到反射。
这是Reflexion的命名空间using System.Reflection;

前面的blog说到C#之Entity framework，提到这段代码：

using (ModelEntities context = new ModelEntities())

{

     context.stocks_EF.Add(new stocks_EF() { Symbol = "CAT", Price = 98.42, PricePct = 2.5, Volume = 29389, AvgVolume = 39392, MktCap = "56.5B", Yield = 2.2, PE = 10.2, TradeDate = Convert.ToDateTime("2013-06-17 00:00:00.000") });

     context.SaveChanges();

}

    public partial class ModelEntities : DbContext

    {

        public DbSet<stocks_EF> stocks_EF { get; set; }

    }

下面我说说怎么用反射写这段代码。
1.已知道类型的Type：Type contextType = typeof(ModelEntities);如果是某instance的type是    
  obj.GetType()
2. 创建某类型的Instance：object context = Activator.CreateInstance(contextType);
3. 获得某Instance的某属性的值：
  object dbSetInstance = contextType.GetProperty(propName).GetValue(context);
4. 获得某Instance的某属性的类型：
    Type dbSetType = contextType.GetProperty(propName).PropertyType;
5.获得某类型的某方法：MethodInfo objAddMethod = dbSetType.GetMethod("Add");
6.Call某方法： objAddMethod.Invoke(dbSetInstance, new object[]{obj});
(eg2)7.获得泛型的参数类型

                if (propType.IsGenericType)

                {

                    Type[] paraList = propType.GetGenericArguments();

                    propertyName = paraList[0].Name;

                }

8.设置某属性的值：t.GetProperty(name).SetValue(obj, "abd")

Type contextType = typeof(ModelEntities);

object context = Activator.CreateInstance(contextType);

Type objType = obj.GetType();

var propNames = from p in contextType.GetProperties() select p.Name;

foreach (var propName in propNames)

{

    if (objType.ToString() == contextType.Namespace+"."+propName)

    {

         object dbSetInstance = contextType.GetProperty(propName).GetValue(context);

         Type dbSetType = contextType.GetProperty(propName).PropertyType;

         MethodInfo objAddMethod = dbSetType.GetMethod("Add");

         objAddMethod.Invoke(dbSetInstance, new object[] { obj });

         MethodInfo objSaveMethod = contextType.GetMethod("SaveChanges");

         objSaveMethod.Invoke(context, null);

     }

}

再训练一个：

    public partial class stocks_EF

    {

        public int ID { get; set; }

        public string Symbol { get; set; }

        public Nullable<double> Price { get; set; }

        public Nullable<double> PricePct { get; set; }

        public Nullable<int> Volume { get; set; }

        public Nullable<int> AvgVolume { get; set; }

        public string MktCap { get; set; }

        public Nullable<double> Yield { get; set; }

        public Nullable<double> PE { get; set; }

        public Nullable<System.DateTime> TradeDate { get; set; }

        public Nullable<System.DateTime> InsertTime { get; set; }

    }

code如下：

public static void Fill(string[] words, object obj)

{

    Type t = obj.GetType();

    var propNames = from p in t.GetProperties() select p.Name;

    int i=0;

    foreach (var name in propNames)

    {

        Type propType = t.GetProperty(name).PropertyType;

        string propertyName = propType.Name;

        if (propType.IsGenericType)

        {

            Type[] paraList = propType.GetGenericArguments();

            propertyName = paraList[0].Name;

        }

        if (propertyName == "DateTime")

            t.GetProperty(name).SetValue(obj, Convert.ToDateTime(words[i]));

        else if (propertyName == "Int32")

            t.GetProperty(name).SetValue(obj, Convert.ToInt32(words[i]));

        else if (propertyName == "Double")

            t.GetProperty(name).SetValue(obj, Convert.ToDouble(words[i]));

        else t.GetProperty(name).SetValue(obj, words[i]);

        i++;

    }

}

main函数：

string[] words = { "1", "CAT", "98.43", "2.5", "29389", "39392", "56.5B", "2.2", "10.2", "2013-06-17 00:00:00.000", "2014-04-23 00:00:00.000" };

 stocks_EF s = new stocks_EF();

 Fill(words, s);