Sunday, November 2, 2008

LINQ - C# Programming

Get DataSource
In C# as in most programming languages a variable must be declared before it can be used. In a LINQ query, the from clause comes first in order to introduce the data source (customers) and the range variable (cust).

//QEmp is an IEnumerable
var QEmp = from e in Emp
select e;


Probably the most common query operation is to apply a filter in the form of a Boolean expression. The filter causes the query to return only those elements for which the expression is true. The result is produced by using the where clause. The filter in effect specifies which elements to exclude from the source sequence.

var QEmp = from e in Emp
where e.Country == "India"
select e

----AND Condition----
where e.Country == "India" && e.Name == "Ashvin"

----OR Condition----
where e.Country == "India" || e.Name == "Ashvin"

The orderby clause will cause the elements in the returned sequence to be sorted according to the default comparer for the type being sorted. For example, the following query can be extended to sort the results based on the Name property. Because Name is a string, the default comparer performs an alphabetical sort from A to Z.
var QEmp = from e in Emp
where e.Country == "India"
orderby e.Name ascending
select e


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