Building a LINQ Provider

One of its features is grouping. Many people understand grouping like it is defined in Sql. Linq is implementing grouping quite the same way. Let's discover this syntax and how to make consecutive groups easier.

I got tried of typing

var result = from s in source
where items.Contains(s)
select s;and so I implemented the IN and NOT IN methods as extension methods:

101 LINQ Example with sample code snippets....This sample prints each element of an input integer array whose value is less than 5. The sample uses a query expression to create a new sequence of integers and then iterates over each element in the sequence, printing its value

When using Linq to objects, you will quickly feel the need to pass some parameters from a method to another but it's not so easy because each Linq method is not calling the following one. In a Linq sequence, each method is using the result computed by the previous one. So, local contexts are not visible from one method to another.
The compiler is using two technical different ways to let parameters go out of a method.

Ok now let's go. Here is just a little trick but with some interesting patterns that could be useful in some other contexts not connected to Linq to Sql.

When using Linq expressions, like with Linq to Sql, translating the expression into something else (sql for example) is taking time and resources. Sometimes it's negligible, sometimes not...

I want to continue to build out the intranet site we've started in our previous articles. A standard item in every intranet is a staff/employee list. Most companies implementing Windows SharePoint Services (WSS) are large enough to have a database that contains all employees. We will use the aggregation features of SharePoint to include data from this database into our intranet.

I've posted an update to this post to apply on demand loading of Details data using ASP.NET AJAX PageMethods. I'm demonstrating the usage if CollapsiblePanelExtender client events on the new post. Check it out.

I admit, Matt Berseth is really inspiring me! Few days ago I pass through 2 of his great posts:

.Surrounding your Data Table and Dialog Controls with ComponentArt Styled Panels
.Building a Grouping Grid with the ASP.NET 3.5 LinqDataSource and ListView Controls
The first one is pure design tips one which I used for making good presentation of my demo here. The 2nd post is actually the idea.

This tutorial will show you how we can extend the LINQ to SQL Class and create methods that will allow us to page data from a SQL database. C# version.

"Building Layered Web Applications" that shows you how to build N-Layer applications with Microsoft ASP.NET 2.0. These articles teach you how to design, build and use custom business objects in your web application. The target audience for this series are developers that are ready to make the switch from using SqlDataSource controls to ObjectDataSource controls with custom business objects. Experience with ASP.NET 2 and C# is necessary while some knowledge about object oriented design certainly helps. The design I am going to show you in these articles is a simplified version of a design you would use in a real world application. It doesn't feature all the necessary functionality your application needs, but instead focuses on the underlying concepts.

A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types.

All lambda expressions use the lambda operator =>, which is read as "goes to". The left side of the lambda operator specifies the input parameters (if any) and the right side holds the expression or statement block. The lambda expression x => x * x is read "x goes to x times x." This expression can be assigned to a delegate type as follows: