Question

我有简单的查询，可以将两个表中的数据加载到GUI中。我将加载的数据保存到广泛可用的对象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;
   }
}

现在如果我愿意：

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。

如果您附加 currentClient，那么关联的对象也应该附加，这意味着当SaveChanges()

时它们会更新

但是您将获得Object with the key exists异常，因为您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，它知道currentClient与objectInDB相同，因此抛出异常。

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
}

Answer 2

经过Kirk的一些工作和帮助，我得到了关于ObjectStateManager的错误，我设法解决了这个问题。此代码允许我将两个更改保存到两个表。

 currentClient.Podmioty.PodmiotOsobaImie = textImie.Text;
 currentClient.Podmioty.PodmiotOsobaNazwisko = textNazwisko.Text;
 currentClient.KlienciHaslo = "TEST1134";
 using (var context = new EntityBazaCRM()) {
       if (context.Kliencis.Any(t => t.KlienciID == currentClient.KlienciID)) {
           context.Podmioties.Attach(currentClient.Podmioty);
           context.Kliencis.Attach(currentClient);
           context.ObjectStateManager.ChangeObjectState(currentClient.Podmioty, EntityState.Modified);
           context.ObjectStateManager.ChangeObjectState(currentClient, EntityState.Modified);
        } else {
           context.Kliencis.AddObject(currentClient);  // save new Client
        }
        context.SaveChanges();
  }

使用实体框架将更改保存回数据库

2 个答案: