Linq增删查改

一、增加

using (var dataContext = new LinqEntityDataContext())

 {

    var addLogin = new tb_login { UserName = "linq", UserPwd = "123" };

    dataContext.tb_logins.InsertOnSubmit(addLogin);

    dataContext.SubmitChanges();

}

 

二、删除

using (var dataContext = new LinqEntityDataContext())

{

    const int id = 6;

    var deleteLogin = dataContext.tb_logins.FirstOrDefault(p => p.Id == id);

     if (deleteLogin != null)

        dataContext.tb_logins.DeleteOnSubmit(deleteLogin);

    dataContext.SubmitChanges();

}

三、查询

using (var dataContext = new LinqEntityDataContext())

{

    var data = dataContext.tb_logins.ToList();

    foreach (var i in data)

    {

        var tb = new TextBlock { Text = i.UserName };

        spRoot.Children.Add(tb);

    }

}

四、修改

using (var dataContext = new LinqEntityDataContext())

{

    const int id = 1;

    var updateLogin = dataContext.tb_logins.FirstOrDefault(p => p.Id == id);

    if (updateLogin != null)

    {

        updateLogin.UserName = "update";

        updateLogin.UserPwd = "abc";

    }

    dataContext.SubmitChanges();  

}