有没有更好的方式在LinqToSQL中进行更新？

Question

我有一个列表（来自客户端的中间件应用程序），我需要把它放在我的数据库中。列表中的某些项目可能已经在数据库中（只需要更新）。其他是新的插入。

事实证明，这比我想象的要困难得多。这是我的代码来做到这一点。我希望有更好的办法：

public void InsertClients(List<Client> clients) 
{ 
    var comparer = new LambdaComparer<Client>((x, y) => x.Id == y.Id); 

    // Get a listing of all the ones we will be updating 
    var alreadyInDB = ctx.Clients 
         .Where(client => clients.Contains(client, comparer)); 

    // Update the changes for those already in the db 
    foreach (Client clientDB in alreadyInDB) 
    { 
     var clientDBClosure = clientDB; 
     Client clientParam = clients.Find(x => x.Id == clientDBClosure.Id); 
     clientDB.ArrivalTime = clientParam.ArrivalTime; 
     clientDB.ClientId = clientParam.ClientId; 
     clientDB.ClientName = clientParam.ClientName; 
     clientDB.ClientEventTime = clientParam.ClientEventTime; 
     clientDB.EmployeeCount = clientParam.EmployeeCount; 
     clientDB.ManagerId = clientParam.ManagerId; 
    } 

    // Get a list of all clients that are not in my the database. 
    var notInDB = clients.Where(x => alreadyInDB.Contains(x, comparer) == false); 

    ctx.Clients.InsertAllOnSubmit(notInDB); 
    ctx.SubmitChanges(); 
} 

这似乎很多工作做一个简单的更新。但也许我只是被宠坏了。

无论如何，如果有更简单的方法来做到这一点，请让我知道。

---

注意：如果你是好奇的代码到LambdaComparer是在这里：http://gist.github.com/335780#file_lambda_comparer.cs

Answer 1

public void ProcessClients(List<Client> tempClients) 
{ 
    foreach (Client client in tempClients) 
    { 
     Client originalClient = ctx.Clients.Where(a => a.Id == client.Id).SingleOrDefault(); 

     if (originalClient != null) 
     { 
      originalClient.ArrivalTime = client.ArrivalTime; 
      originalClient.ClientId = client.ClientId; 
      originalClient.ClientName = client.ClientName; 
      originalClient.ClientEventTime = client.ClientEventTime; 
      originalClient.EmployeeCount = client.EmployeeCount; 
      originalClient.ManagerId = client.ManagerId; 
     } 
     else 
     { 
      ctx.Clients.InsertOnSubmit(client); 
     } 
    } 

    ctx.SubmitChanges(); 
} 

Answer 2

没有更好的办法，但一种替代方案：

ctx.AddtoClients(notInDB); 
ctx.SaveChanges();