使用实体框架将更改保存回数据库

Question

我有简单的查询,将两个表中的数据加载到GUI中.我正在将加载的数据保存到广泛可用的对象中Clients currentlySelectedClient.

using (var context = new EntityBazaCRM()) 
{
   currentlySelectedClient = context.Kliencis.Include("Podmioty").FirstOrDefault(d => d.KlienciID == klientId);
   if (currentlySelectedClient != null) 
   {
      textImie.Text = currentlySelectedClient.Podmioty.PodmiotOsobaImie;
      textNazwisko.Text = currentlySelectedClient.Podmioty.PodmiotOsobaNazwisko;
   } 
   else 
   {
      textNazwa.Text = currentlySelectedClient.Podmioty.PodmiotFirmaNazwa;
   }
}

所以现在如果我想:

1)保存用户所做的更改我该怎么做？我是否必须在数据库方面准备一些东西？如何处理修改多个表(某些数据在这里,有些数据在那里)？我现在的代码好像写了.KlienciHaslo就好了,但它根本不影响Podmioty.我尝试了不同的组合,但没有运气.

2)将新客户端添加到数据库(并将信息保存到相关表)？

    currentClient.Podmioty.PodmiotOsobaImie = textImie.Text;  // not saved
    currentClient.Podmioty.PodmiotOsobaNazwisko = textNazwisko.Text; // not saved
    currentClient.KlienciHaslo = "TEST111"; // saved

    using (var context = new EntityBazaCRM()) 
    {
        var objectInDB = context.Kliencis.SingleOrDefault(t => t.KlienciID == currentClient.KlienciID);
        if (objectInDB != null) 
        {
           // context.ObjectStateManager.ChangeObjectState(currentClient.Podmioty, EntityState.Modified);
           //context.Podmioties.Attach(currentClient.Podmioty);
           context.Kliencis.ApplyCurrentValues(currentClient); // update current client
           //context.ApplyCurrentValues("Podmioty", currentClient.Podmioty); // update current client
        } 
        else 
        {
           context.Kliencis.AddObject(currentClient);  // save new Client
        }
        context.SaveChanges();
     }

我如何实现这两个目标？

编辑答案(不保存任何内容):

currentClient.Podmioty.PodmiotOsobaImie = textImie.Text; // no save
currentClient.Podmioty.PodmiotOsobaNazwisko = textNazwisko.Text; // no save
currentClient.KlienciHaslo = "TEST1134"; // no save

using (var context = new EntityBazaCRM()) 
{
    if (context.Kliencis.Any(t => t.KlienciID == currentClient.KlienciID)) 
    {
        context.Kliencis.Attach(currentClient); // update current client
    } 
    else 
    {
        context.Kliencis.AddObject(currentClient);  // save new Client
    }
    context.SaveChanges();
}            

Answer 1

显然,ApplyCurrentValues仅适用于标量属性.

如果你附加了currentClient当时关联的对象也应该附加,这意味着它们会在你被更新时更新SaveChanges()

但是你会得到一个Object with the key exists例外,因为你已经将数据库中的对象加载到objectInDB变量中.上下文只能包含一个实体的副本,并且它知道currentClient与objectInDB抛出异常的内容相同.

请尝试使用此模式

if (context.Kliencis.Any(t => t.KlienciID == currentClient.KlienciID)) 
{
    context.Kliencis.Attach(currentClient); // update current client
} 
else 
{
    context.Kliencis.AddObject(currentClient);  // save new Client
}

或者,如果您使用身份作为ID,那么

// if the ID is != 0 then it's an existing database record
if (currentClient.KlienciID != 0) 
{
    context.Kliencis.Attach(currentClient); // update current client
} 
else // the ID is 0; it's a new record
{
    context.Kliencis.AddObject(currentClient);  // save new Client
}