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();  
}