动态创建类

    public class CreateClassHelper
    {
        /// <summary>
        /// 根据列名创建自定义类型
        /// 属性名称在列名前添加前缀 prdfix
        /// </summary>
        /// <param name="columnNames">用来创建属性的列名</param>
        /// <param name="prdfix">属性名称在列名前添加的前缀</param>
        /// <returns></returns>
        public static Type CreateClass(string[] columnNames, string prdfix=null)
        {
            
            DynamicTypeBuilder dyClass = new DynamicTypeBuilder("dy");//创建动态类，dy可以随便替换  
            //ColInfos为已经取到的列信息集合  
            foreach (string name in columnNames)
            {
                try
                {
                    dyClass.AppendPublicProperty(prdfix + name, typeof(string));//同时动态添加公共属性到自定义类  
                }
                catch (Exception ex)
                {
                    LogHelper.log4net_Error(ex.Message.ToString(), null);
                }        
            }
            Type dyType = dyClass.CreateDynamicType();//创建自定义类   
            return dyType;
        }
    }
    public class DynamicTypeBuilder
    {
        TypeBuilder tb;
        /// <summary>  
        /// 构造函数  
        /// </summary>  
        /// <param name="typeNm">动态类型的名称</param>  
        public DynamicTypeBuilder(string typeNm)
        {
            // 在 Silverlight 中 AssemblyBuilderAccess 没有 RunAndSave  
            AssemblyBuilder ab = AppDomain.CurrentDomain.DefineDynamicAssembly(
                new AssemblyName("TempAssembly"), AssemblyBuilderAccess.Run);

            ModuleBuilder mb = ab.DefineDynamicModule("TempModule");
            this.tb = mb.DefineType(typeNm, TypeAttributes.Public);
        }
        /// <summary>  
        /// 添加一个public的可读写属性，并且会创建对应的名为 propertyNm + "Field" 的私有字段  
        /// </summary>  
        /// <param name="propertyNm"></param>  
        /// <param name="type"></param>  
        public void AppendPublicProperty(string propertyNm, Type type)
        {
            this.AppendPublicProperty(propertyNm, type, true, true);
        }
        /// <summary>  
        /// 添加一个public属性，并且会创建对应的名为 propertyNm + "Field" 的私有字段  
        /// </summary>  
        /// <param name="propertyNm"></param>  
        /// <param name="type"></param>  
        /// <param name="canGet">是否实现getter</param>  
        /// <param name="canSet">是否实现setter</param>  
        public void AppendPublicProperty(string propertyNm, Type type, bool canGet, bool canSet)
        {
            FieldBuilder field = this.tb.DefineField(string.Format("{0}Field", propertyNm), type, FieldAttributes.Private);

            PropertyBuilder property = tb.DefineProperty(propertyNm, PropertyAttributes.HasDefault, type, null);

            MethodAttributes getSetAttr = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;

            if (canGet)
            {
                MethodBuilder getAccessor = tb.DefineMethod(string.Format("get_{0}", propertyNm), getSetAttr, type, Type.EmptyTypes);
                ILGenerator getIL = getAccessor.GetILGenerator();
                // For an instance property, argument default is the instance. Load the  
                // instance, then load the private field and return, leaving the  
                // field value on the stack.  
                getIL.Emit(OpCodes.Ldarg_0);
                getIL.Emit(OpCodes.Ldfld, field);
                getIL.Emit(OpCodes.Ret);
                property.SetGetMethod(getAccessor);
            }

            if (canSet)
            {
                MethodBuilder setAccessor = tb.DefineMethod(string.Format("set_{0}", propertyNm), getSetAttr, null, new Type[] { type });
                setAccessor.DefineParameter(1, ParameterAttributes.None, "value");
                ILGenerator setIL = setAccessor.GetILGenerator();
                // Load the instance and then the numeric argument, then store the  
                // argument in the field.  
                setIL.Emit(OpCodes.Ldarg_0);
                setIL.Emit(OpCodes.Ldarg_1);
                setIL.Emit(OpCodes.Stfld, field);
                setIL.Emit(OpCodes.Ret);
                property.SetSetMethod(setAccessor);
            }
        }
        /// <summary>  
        /// 在添加完各个 public 属性之后，调用此方法以完成对动态类型的定义并加载之，  
        /// 此后通过 Activator.CreateInstance() 便可实例化动态类型  
        /// </summary>  
        /// <returns></returns>  
        public Type CreateDynamicType()
        {
            return this.tb.CreateType();
        }
    }