LINQ (Language Integrated Query)
LINQ (Language Integrated Query)
LINQ is great feature .NET is providing us, Using LINQ we can filter, sort and traverse collections object, actually you can make use of SQL (Structured Query Language) syntax in .NET to filter or sort or traverse collection object
Syntax:
IEnumerable<T> var = from obj in CollectionObj
Where condition
Order by obj
Select obj
Example:
Step 1: Create a .NET web application
Setp 2: Add one listbox, textbox and a button
Setp 3: import Generics name space and add a private variable names to default.aspx.cs
using System.Collections.Generic;
private string[] names = { “Satish”, “Gopal”, “Pinky”, “Krishna”, “Kumar”, “Veera”, “Harish”, “Achyut” };
Setp 4: Write following code in Page_Load method
if (!Page.IsPostBack)
{
foreach (string item in names)
ListBox1.Items.Add(item);
}
Setp5:
Double click on button and write a button click event and add following code
protected void Button1_Click(object sender, EventArgs e)
{
IEnumerable<string> query = from s in names
where s.Contains(TextBox1.Text)
orderby s
select s;
ListBox1.Items.Clear();
foreach (string item in query)
ListBox1.Items.Add(item);
}
Here we are finding some names with entered criteria, in the first line of code we make using of generics IEnumerable string and finding out the name which are having specific criteria.
where s.Contains(TextBox1.Text) it searched through the names array and find out the names which contains entered text
orderby s order by clause
select s and selecting the names into query.
Now build go and enter some value in the text box and test.
Happy coding.
Regards,
Satish.