EF增删查改

一、增加

using (var entities = new TrainingDemoEntities())
{
    ar addLogin = new tb_login();
    addLogin.UserName = "entity";
    addLogin.UserPwd = "entityPwd";
    entities.tb_login.AddObject(addLogin);
    entities.SaveChanges();
}

二、删除

using (var entities = new TrainingDemoEntities())
{
    int id = 8;
    var data = entities.tb_login.FirstOrDefault(p => p.Id == id);
    if (data != null)
    {
         entities.tb_login.DeleteObject(data);
         entities.SaveChanges();
    }    
}

三、查询

using (var entities = new TrainingDemoEntities())
{
    var data = entities.tb_login.ToList();
    foreach (var i in data)
    {
        var tb = new TextBlock { Text = i.UserName };
        spRoot.Children.Add(tb);
    }
}

四、修改

using (var entities = new TrainingDemoEntities())
{
    int id = 7;
    var data = entities.tb_login.FirstOrDefault(p => p.Id == id);
    if (data != null)
    {
        data.UserName = "update";
        data.UserPwd = "updatePwd";
        entities.SaveChanges();
    }
}