• 实例属性的读取

.method public hidebysig instance string AAA() cil managed
{.maxstack 8L_0000: call string blqw.IL.Demo.Program/MyClass::get_Name()L_0005: ret
} 

string AAA()
{return MyClass.Name;
}

C#代码

.method private hidebysig instance string AAA(class blqw.IL.Demo.Program/MyClass my) cil managed
{.maxstack 8L_0000: ldarg.0 L_0001: callvirt instance string blqw.IL.Demo.Program/MyClass::get_Name()L_0006: ret
}

string AAA(MyClass my)
{return my.Name;
}

C#代码

//     将索引为 0 的参数加载到计算堆栈上。
public static readonly OpCode Ldarg_0;

public static Func<MyClass, string> ILTest()
{var type = typeof(MyClass);var prop = type.GetProperty("Name");//反射属性var dm = new DynamicMethod("", typeof(string), new[] { typeof(MyClass) }, type);var il = dm.GetILGenerator();il.Emit(OpCodes.Ldarg_0);il.Emit(OpCodes.Callvirt, prop.GetGetMethod());il.Emit(OpCodes.Ret);return (Func<MyClass, string>)dm.CreateDelegate(typeof(Func<MyClass, string>));
}

• 实例属性的设置

.method private hidebysig instance void AAA(class blqw.IL.Demo.Program/MyClass my, string name) cil managed
{.maxstack 8L_0000: ldarg.0 L_0001: ldarg.1 L_0002: callvirt instance void blqw.IL.Demo.Program/MyClass::set_Name(string)L_0007: ret
}

public static Action<MyClass, string> ILTest()
{var type = typeof(MyClass);var prop = type.GetProperty("Name");//反射属性var dm = new DynamicMethod("", null, new[] { typeof(MyClass), typeof(string) }, type);var il = dm.GetILGenerator();il.Emit(OpCodes.Ldarg_0);il.Emit(OpCodes.Ldarg_1);il.Emit(OpCodes.Callvirt, prop.GetSetMethod());il.Emit(OpCodes.Ret);return (Action<MyClass, string>)dm.CreateDelegate(typeof(Action<MyClass, string>));
}

• 实际应用

public delegate void PropertySetter(object instance, object value);
public static PropertySetter CreateSetter(PropertyInfo property)
{var type = property.DeclaringType;var dm = new DynamicMethod("", null, new[] { typeof(object), typeof(object) }, type);//=== IL ===var il = dm.GetILGenerator();il.Emit(OpCodes.Ldarg_0);il.Emit(OpCodes.Ldarg_1);if (property.PropertyType.IsValueType)//判断属性类型是否是值类型
    {il.Emit(OpCodes.Unbox,property.PropertyType);//如果是值类型就拆箱
    }else{il.Emit(OpCodes.Castclass, property.PropertyType);//否则强转
    }il.Emit(OpCodes.Callvirt, property.GetSetMethod());il.Emit(OpCodes.Ret);//=== IL ===return (PropertySetter)dm.CreateDelegate(typeof(PropertySetter));
}

public class ObjectProperty
{public PropertyInfo Info { get; set; }public PropertySetter Setter { get; set; }
}

static readonly Dictionary<Type, ObjectProperty[]> Cache = new Dictionary<Type, ObjectProperty[]>();public static ObjectProperty[] GetProperties(Type type)
{ObjectProperty[] arr;if (Cache.TryGetValue(type, out arr))//优先从缓存中获取
    {return arr;}PropertyInfo[] ps = type.GetProperties(); arr = new ObjectProperty[ps.Length];for (int i = 0; i < ps.Length; i++){ObjectProperty op = new ObjectProperty();op.Info = ps[i];op.Setter = CreateSetter(op.Info);  //之前定义的方法arr[i] = op;}Cache.Add(type, arr); //加入缓存return arr;
}

public class ObjectProperty
{/// <summary> 属性信息/// </summary>public PropertyInfo Info { get; set; }/// <summary> Set方法委托/// </summary>public PropertySetter Setter { get; set; }//缓存static readonly Dictionary<Type, ObjectProperty[]> Cache = new Dictionary<Type, ObjectProperty[]>();/// <summary> 获取一个类中的所有公开实例属性和它们的Set方法委托/// </summary>public static ObjectProperty[] GetProperties(Type type){ObjectProperty[] arr;if (Cache.TryGetValue(type, out arr))//优先从缓存中获取
        {return arr;}PropertyInfo[] ps = type.GetProperties();arr = new ObjectProperty[ps.Length];for (int i = 0; i < ps.Length; i++){ObjectProperty op = new ObjectProperty();op.Info = ps[i];op.Setter = CreateSetter(op.Info);  //之前定义的方法arr[i] = op;}Cache.Add(type, arr); //加入缓存return arr;}/// <summary> 创建指定属性的Set方法委托/// </summary>public static PropertySetter CreateSetter(PropertyInfo property){var type = property.DeclaringType;var dm = new DynamicMethod("", null, new[] { typeof(object), typeof(object) }, type);//=== IL ===var il = dm.GetILGenerator();il.Emit(OpCodes.Ldarg_0);il.Emit(OpCodes.Ldarg_1);if (property.PropertyType.IsValueType)//判断属性类型是否是值类型
        {il.Emit(OpCodes.Unbox, property.PropertyType);//如果是值类型就拆箱
        }else{il.Emit(OpCodes.Castclass, property.PropertyType);//否则强转
        }il.Emit(OpCodes.Callvirt, property.GetSetMethod());il.Emit(OpCodes.Ret);//=== IL ===return (PropertySetter)dm.CreateDelegate(typeof(PropertySetter));}
}

C#代码

public static List<T> ConvertToModels<T>(DataSet ds)where T : new()
{var prop = ObjectProperty.GetProperties(typeof(T));List<T> list = new List<T>(ds.Tables[0].Rows.Count);var cols = ds.Tables[0].Columns;foreach (DataRow row in ds.Tables[0].Rows){T m = new T();foreach (var p in prop){if (cols.Contains(p.Info.Name)){var val = row[p.Info.Name];if ((val is DBNull) == false){p.Setter(m, val);}}}list.Add(m);}return list;
}

public class User
{public User(){}public int Id { get; set; }public string Name { get; set; }public bool Sex { get; set; }public Guid Uid { get; set; }public DateTime Time { get; set; }public string SexText{get{return Sex ? "男" : "女";}set{Sex = (value == "男");}}
}
//模拟方法
static public DataSet GetDataSet(string sql)
{DataTable table = new DataTable("User");table.Columns.Add("Id", typeof(int));table.Columns.Add("Name", typeof(string));table.Columns.Add("Sex", typeof(bool));table.Columns.Add("Uid", typeof(Guid));table.Columns.Add("Time", typeof(DateTime));table.Columns.Add("多出来的属性", typeof(string));for (int i = 0; i < 20; i++){table.Rows.Add(i, "blqw" + i, true, Guid.NewGuid(), DateTime.Now, "多余的");}DataSet ds = new DataSet();ds.Tables.Add(table);return ds;
}

C#代码

• 反射和IL

static public List<T> ConvertToModels2<T>(DataSet ds)where T : new()
{var prop = ObjectProperty.GetProperties(typeof(T));List<T> list = new List<T>(ds.Tables[0].Rows.Count);var cols = ds.Tables[0].Columns;foreach (DataRow row in ds.Tables[0].Rows){T m = new T();foreach (var p in prop){if (cols.Contains(p.Info.Name)){var val = row[p.Info.Name];if (Convert.IsDBNull(val) == false){p.Info.SetValue(m, val, null);//这里直接用反射的SetValue
                }}}list.Add(m);}return list;
}

反射代码