The types and the names of the properties in the anonymous types must match: new { p1 = q.QOT_SEC_ID, p2 = dpr.DPR_TS } equals new { p1 = (decimal)p.PAY_SEC_ID, p2 = p.PAY_DATE } or if p.PAY_SEC_ID were an int?: new { p1 = (int?)q.QOT_SEC_ID, p2 = dpr.DPR_TS } equals new { p1 = p.PAY_SEC_ID, p2 … Read more
You cannot use properties that are not mapped to a database column in a Where expression. You must build the expression based on mapped properties, like: var date = DateTime.Now.AddYears(-from); result = result.Where(p => date >= p.DOB); // you don’t need `AsQueryable()` here because result is an `IQueryable` anyway As a replacement for your not … Read more
A while back I wrote a 4 part blog series (Parts 1, 2, 3 and 4) covering doing bulk updates (with one command) in the Entity Framework. While the focus of that series was update, you could definitely use the principles involved to do delete. So you should be able to write something like this: … Read more
Update: EF ≥ 4 supports Contains directly (Checkout Any), so you don’t need any workaround. public static IQueryable<TEntity> WhereIn<TEntity, TValue> ( this ObjectQuery<TEntity> query, Expression<Func<TEntity, TValue>> selector, IEnumerable<TValue> collection ) { if (selector == null) throw new ArgumentNullException(“selector”); if (collection == null) throw new ArgumentNullException(“collection”); if (!collection.Any()) return query.Where(t => false); ParameterExpression p = selector.Parameters.Single(); … Read more
Entity Framework is trying to execute your projection on the SQL side, where there is no equivalent to string.Format. Use AsEnumerable() to force evaluation of that part with Linq to Objects. Based on the previous answer I have given you I would restructure your query like this: int statusReceived = (int)InvoiceStatuses.Received; var areaIds = user.Areas.Select(x=> … Read more
Do that like this db.Users.OrderByDescending(u => u.UserId).FirstOrDefault();
Reason: By design, LINQ to Entities requires the whole LINQ query expression to be translated to a server query. Only a few uncorrelated subexpressions (expressions in the query that do not depend on the results from the server) are evaluated on the client before the query is translated. Arbitrary method invocations that do not have … Read more
adapted from MSDN, how to left join using EF 4 var query = from u in usergroups join p in UsergroupPrices on u.UsergroupID equals p.UsergroupID into gj from x in gj.DefaultIfEmpty() select new { UsergroupID = u.UsergroupID, UsergroupName = u.UsergroupName, Price = (x == null ? String.Empty : x.Price) };
You need to add a reference to the .NET assembly System.Data.Entity.dll.
I would offer this alternative to what everyone else has posted. System.Reflection.PropertyInfo prop = typeof(YourType).GetProperty(“PropertyName”); query = query.OrderBy(x => prop.GetValue(x, null)); This avoids repeated calls to the reflection API for obtaining the property. Now the only repeated call is obtaining the value. However I would advocate using a PropertyDescriptor instead, as this will allow for … Read more