LINQ to SQL additions and deletions (reprint)

Code

Code highlighting produced by Actipro Codehighlighter (freeware) http://www.CodeHighlighter.com/-->using System;

Using System.Collections.Generic;

Using System.Linq;

Using System.Web;

Using System.Web.UI;

Using System.Web.UI.WebControls;

Using System.Data.Common;

Using System.Collections.Generic;

Namespace Firstlinq

{

public partial class _default:system.web.ui.page

{

NorthwindDataContext CTX = new NorthwindDataContext ("Data source=zhangshuqiang;initial catalog=northwind; Persist Security info=true; User Id=sa; Password=sa ");

protected void Page_Load (object sender, EventArgs e)

{

LINQ1 ();

LINQ2 ();

Linq3 ();

}

<summary>

Change and delete

</summary>

private void Linq3 ()

{

Increase

T_user User = new T_user ();

User. UserName = "big Weather";

User. PWD = "123456";

Ctx.t_User.InsertOnSubmit (User);//The previous method is add ();

CTx. SubmitChanges ();

Change

Refer to this syntax string s = (from A in CTX. Customers Select a). Single (a = a.ID = = 2);

T_user userupdate = ctx.t_User.SingleOrDefault (T_user = t_user.id = 2);//single is no different from Singleordefault

Userupdate.username = "big weather 1";

CTx. SubmitChanges ();

By deleting

T_user Userdelete = (from UserInfo in ctx.t_user where userinfo.id = = 1 Select userinfo). FirstOrDefault ();

if (userdelete! = null)

{

Ctx.t_User.DeleteOnSubmit (Userdelete);

CTx. SubmitChanges ();

}

}

<summary>

Familiarity with LINQ to SQL syntax

</summary>

private void Linq2 ()

{

Customers customer = new Customers ();

Execute normal SQL statements and query customerid= "ANATR" records

Ienumerable<customers> Customers = ctx. Executequery<customers> ("select * from Customers where customerid= ' Anatr '");

Customer = Customers. First ();

Response.Write (Customer. CustomerID);

Querying a single record using LINQ

var cus = from C in CTX. Customers where C.customerid.equals ("Anatr") select C;

Customer = cus. First ();

Response.Write (Customer.companyname);

Query result set, syntax: From temporary table name in table collection by the name of the temporary table. Field name upgrade select temporary table name

Gdvcustomers.datasource = from Cust in CTX. Customers where Cust. CustomerID! = "Anatr" by Cust.companyname descending select Cust;

Gdvcustomers.databind ();

}

<summary>

Familiarize yourself with the LINQ syntax, where variables are defined like JS, without declaring types.

</summary>

private void Linq1 ()

{

var age = 29;

var username = "Greatverve";

var userlist = new[] {"A", "B", "C"};

foreach (var user in userlist)

{

Response.Write (user);

}

}

}

}

Http://www.cnblogs.com/greatverve/archive/2010/05/13/1734236.html

LINQ to SQL additions and deletions (reprint)