Linq动态、多条件拼接方法(WCF RIA Services、Domain Service、EF）

终于解决了Linq动态、多条件在EF、RIA、DS里面的用法，整理了相关参考地址。

 

PredicateBuilder（Expressions扩展）
http://www.albahari.com/nutshell/linqkit.aspx

System.Linq.Dynamic （Dynamic.cs）扩展类
可以在VS自带demo里找到。
(VS2010目录C:\Program Files (x86)\Microsoft Visual Studio 10.0\Samples\2052\CSharpSamples.zip-CSharpSamples\LinqSamples\DynamicQuery)

 

相关
动态模糊查询
http://stackoverflow.com/questions/4599989/how-dynamic-library-system-linq-dynamic-support-like-operator
动态查询语法
http://www.beansoftware.com/ASP.NET-Tutorials/Dynamic-LINQ.aspx
动态创建在WCF RIA Services
http://weblogs.asp.net/fredriknormen/archive/2009/12/30/wcf-ria-services-dynamically-create-a-criteria-on-the-client-side.aspx

 

其他
Writing Dynamic Linq Queries in Linq-to-Entities
http://naspinski.net/post/Writing-Dynamic-Linq-Queries-in-Linq-to-Entities.aspx
LINQ – LINQKit(PredicateBuilder)
http://www.dotblogs.com.tw/alonstar/archive/2010/06/30/16274.aspx

Expression<Func<T, bool>>相关，这东西我还没玩转，在DomainServices里不好使。
Building LINQ Queries at Runtime in C#
http://tomasp.net/blog/dynamic-linq-queries.aspx
linq to sql 多条件组合查询
http://www.cnblogs.com/ChaosHero/archive/2010/06/20/1761444.html

Linq动态查询与模糊查询（带源码示例）
http://www.cnblogs.com/killuakun/archive/2008/08/03/1259389.html 他用的PredicateBuilder，思路清晰，简单。
LINQ体验(17)——LINQ to SQL语句之动态查询
http://www.cnblogs.com/lyj/archive/2008/03/25/1122157.html

Linq To Sql进阶系列（六）用object的动态查询与保存log篇
http://www.cnblogs.com/126/archive/2007/09/09/887723.html
浅谈Linq To Sql集成数据库语言的优劣
http://www.bccn.net/Article/sjk/sqlserver/jszl/200709/6578.html

 

贴个例子，基本解决了string、int、datetime、bool类型的拼接方法，特别注意下如果拼成一条string的格式写法，用参数传递格式就不太重要了

 

MVVM-ViewModels



private LoadOperation<V_Store> LoadSampleEntities()

        {

            this.CanLoad = false;



            string strWhere = " 1=1";

            if (!string.IsNullOrWhiteSpace(Tt_Company)) strWhere += " and co_Company.Contains(\"" + Tt_Company + "\")";

            if (!string.IsNullOrWhiteSpace(Tt_Name)) strWhere += " and co_Name.Contains(\"" + Tt_Name + "\")";

            if (!string.IsNullOrWhiteSpace(Tt_MPa)) strWhere += " and co_MPa.Contains(\"" + Tt_MPa + "\")";

            if (!string.IsNullOrWhiteSpace(Tt_Spec)) strWhere += " and co_Spec.Contains(\"" + Tt_Spec + "\")";

            if (!string.IsNullOrWhiteSpace(Tt_Mill)) strWhere += " and co_Mill.Contains(\"" + Tt_Mill + "\")";

            if (!string.IsNullOrWhiteSpace(Tt_Remark)) strWhere += " and co_Remark.Contains(\"" + Tt_Remark + "\")";

            if (!string.IsNullOrWhiteSpace(Tt_StartAmount) && Utils.IsNumeric(Tt_StartAmount))

            {//数量

                Decimal SAmount = Decimal.Parse(Tt_StartAmount);

                strWhere += " and co_Amount >= " + SAmount;

            }

            if (!string.IsNullOrWhiteSpace(Tt_EndAmount) && Utils.IsNumeric(Tt_EndAmount))

            {

                Decimal EAmount = Decimal.Parse(Tt_EndAmount);

                strWhere += " and co_Amount <= " + EAmount;

            }

            if (!string.IsNullOrWhiteSpace(Tt_StartWeight) && Utils.IsNumeric(Tt_StartWeight))

            {//重量

                Decimal SWeight = Decimal.Parse(Tt_StartWeight);

                strWhere += " and co_Weight >= " + SWeight;

            }

            if (!string.IsNullOrWhiteSpace(Tt_EndWeight) && Utils.IsNumeric(Tt_EndWeight))

            {

                Decimal EWeight = Decimal.Parse(Tt_EndWeight);

                strWhere += " and co_Weight <= " + EWeight;

            }

            if (!string.IsNullOrWhiteSpace(Dt_StartTime))

            {//时间

                DateTime STime = DateTime.Parse(Dt_StartTime);

                string STimeFormat = STime.ToString("yyyy,MM,dd");

                strWhere += " and co_UpDateTime >= DateTime(" + STimeFormat + ")";

            }

            if (!string.IsNullOrWhiteSpace(Dt_EndTime))

            {

                DateTime ETime = DateTime.Parse(Dt_EndTime).AddDays(1);

                string ETimeFormat = ETime.ToString("yyyy,MM,dd");

                strWhere += " and co_UpDateTime <= DateTime(" + ETimeFormat + ")";

            }

            if (Ci_IsZero) strWhere += " and co_Amount != 0 and co_Weight != 0";



 //截入条件，返回一个查询后的Sum结果。


            InvokeOperation<decimal> invokeOperation = ds.GetV_StoreWeightSum(strWhere, OnInvokeCallback, null); 



 //载入了相同的条件，查询后返回记录。

            return ds.Load(ds.GetV_StoreWhereQuery(strWhere).SortAndPageBy(_view)); 

 }





DomainService



        public IQueryable<V_Store> GetV_StoreWhere(string strWhere)

        {

             return ObjectContext.V_Store.Where(strWhere, new object[] { }).OrderByDescending(e => e.co_StoreID);

        }



        [Invoke]

        public decimal GetV_StoreWeightSum(string strWhere)

        {

            return ObjectContext.V_Store.Where(strWhere, new object[] { }).Sum(e => e.co_Weight);
 
       
}