Recently I’ve been working with LINQ so I thought i’d do a quick post to share the two basic LINQ approaches.
First up is an example of a query that returns a collection of objects. In this case they are RouteItem objects.
// The LINQ Query var routesInDB = from RouteItem route in DB.routeItems select route; // Populate a ObservableCollection with the query results. routeItems = new ObservableCollection<RouteItem>(routesInDB);
The second example is for when you want to get one item from a query similar to “SELECT TOP 1″ or “SELECT … Limit 1″ in SQL.
// The LINQ Query IQueryable<setting> cityQuery = from c in DB.setting where c.ID == 1 select c; // populate the setting object with the query result. setting sett = cityQuery.FirstOrDefault();
The example above shows the returning of a single setting object instead of a collection.
The final example shows how to get the number of results. This may be useful if you wanted to see if an item was already present in the collection.
// The LINQ Query var query = from c in routeItems where c.routeName == "home" select c; // get the size of the returned result set. int size = new ObservableCollection<RouteItem>(query).Count;
This example shows a query to count how many RouteItems have the name “home”. We place the result into an int variable.