Change where (s.crmc_Retail_Trade_Id == tradeId) to where (s.crmc_Retail_Trade_Id == tradeId || (tradeId == null && s.crmc_Retail_Trade_Id == null)) Edit – based on this post by Brant Lamborn, it looks like the following would do what you want: where (object.Equals(s.crmc_Retail_Trade_Id, tradeId)) The Null Semantics (LINQ to SQL) MSDN page links to some interesting info: LINQ to … Read more
My LINQ query result cache is probably just what you’re looking for. var q = from c in context.Customers where c.City == “London” select new { c.Name, c.Phone }; var result = q.Take(10).FromCache(); Pete.
Code for joining 3 tables is: var list = dc.Orders. Join(dc.Order_Details, o => o.OrderID, od => od.OrderID, (o, od) => new { OrderID = o.OrderID, OrderDate = o.OrderDate, ShipName = o.ShipName, Quantity = od.Quantity, UnitPrice = od.UnitPrice, ProductID = od.ProductID }).Join(dc.Products, a => a.ProductID, p => p.ProductID, (a, p) => new { OrderID = a.OrderID, … Read more
The following expression will select only distinct companies and return the first occurence with its id. partnerService.SelectPartners().GroupBy(p => p.Name).Select(g => g.First());
What about: itemsInCart.AsEnumerable().Sum(o=>o.Price); AsEnumerable makes the difference, this query will execute locally (Linq To Objects).
from item in db.vw_Dropship_OrderItems where (listStatus != null ? listStatus.Contains(item.StatusCode) : true) && (listMerchants != null ? listMerchants.Contains(item.MerchantId) : true) select item; Might give strange behavior if both listMerchants and listStatus are both null.
Curiously, per MSDN String.IsNullOrEmpty is supported (by virtue of it not being unsupported), yet I can only find complaints about it not being supported. However, if it does work you should not explicitly compare it to a boolean value, instead: var results = from result in context.Records /*XXX broke 🙁 where !String.IsNullOrEmpty(result.Info) */ where !(result.Info … Read more
The DBML file is not related to the database server at all. It’s a completely client side thing. It’s essentially a set of information about your tables in the database and how you’re going to map them to .NET objects. Of course, you can drag a table from a database and have Visual Studio infer … Read more
I had this same issue. The way I got round this was to use the Selecting event on the LinqDataSource and return the result manually. e.g. protected void lnqRecentOrder_Selecting(object sender, LinqDataSourceSelectEventArgs e) { DataClassesDataContext dx = new DataClassesDataContext(); e.Result = (from o in dx.Orders where o.CustomerID == Int32.Parse(Request.QueryString[“CustomerID”]) select o).Take(5); }
While you cant expand them to columns, you can simply return the entities. Eg: select new { CTLJCRJOB, CTLRFDSTM } If you need it flattened, then you will have to write out the mapping yourself, but will still be very trivial.