Rick Strahl has a nice article about your options: http://www.west-wind.com/weblog/posts/246222.aspx. See also: LINQ to SQL – where does your DataContext live?. You may want a slightly different strategy for each type of deployment – web, desktop, windows service… Summarized, your options are: Global DataContext – dangerous in multi-threaded environments (including web apps). Remember that instance … Read more
C# has Convert.ToInt32() which should do what you’re looking for.
This might work… from p in db.products select new { Owner = (p.price > 0 ? from q in db.Users select q.Name : from r in db.ExternalUsers select r.Name) }
Instead of putting it into an own list by calling ToList() or ToArray() i would prefer to use AsEnumerable(). Additionally like the others you should try OrderByDescending() Instead of Count() i would use Any().
Collections are not generally very useful for DAL returns, because a collection does not implicitly guarantee order. It’s just a bucket of items. An IList, on the other hand, does implicitly guarantee order. So we’re down to IEnumerable or IList. The next question would be: is the List object “live”? i.e., is it connected to … Read more
Using query syntax: from c in dbo.Companies join p in dbo.Persons on c.AccountCoordinatorPersonId equals p.PersonId join p2 in dbo.Persons on c.AccountManagerPersonId equals p2.PersonId select new { c.CompanyId, c.CompanyName, AccountCoordinator = p.FirstName + ‘ ‘ + p.Surname, AccountManager = p2.FirstName + ‘ ‘ + p2.Surname } Using method chaining: dbo.Companies.Join(dbo.Persons, c => c.AccountCoordinatorPersonId, p => p.PersonId, … Read more
You can use SQLMetal.exe to generate your dbml and or cs/vb file. Use a pre-build script to start it and target the directory where your datacontext project belongs. C:\Program Files\Microsoft SDKs\Windows\v6.0A\Bin\x64\sqlmetal.exe /server:<SERVER> /database:<database> /code:”path\Solution\DataContextProject\dbContext.cs” /language:csharp /namespace:<your namespace>
This will do the trick: LINQ Query Syntax: from p in m.Items group p by 1 into g select new { SumTotal = g.Sum(x => x.Total), SumDone = g.Sum(x => x.Done) }; LINQ Method Syntax: m.Items .GroupBy(r => 1) .Select(g => new { SumTotal = g.Sum(x => x.Total), SumDone = g.Sum(x => x.Done) }); Notice … Read more
Well, you can just put multiple “where” clauses in directly, but I don’t think you want to. Multiple “where” clauses ends up with a more restrictive filter – I think you want a less restrictive one. I think you really want: DataTable tempData = (DataTable)grdUsageRecords.DataSource; var query = from r in tempData.AsEnumerable() where r.Field<string>(“UserName”) != … Read more
Thats nasty, but simple: Check if the data types for all fields in the O/R-Designer match the data types in your SQL table. Double check for nullable! A column should be either nullable in both the O/R-Designer and SQL, or not nullable in both. For example, a NVARCHAR column “title” is marked as NULLable in … Read more