ASP.NET MVC - EF代码首先不希望在我的数据库

Question

来创建一个行我有这样的一段代码：

var data = context.Accounts.Where(a => a.UserName == User.Identity.Name).Select(a => a.UserAddons).SingleOrDefault(); 
if (data == null) 
    data = new UserAddons(); 
{setting up properties of data} 
context.SaveChanges(); 

我想它来创建UserAddons的新行。但它不想。我是否需要选择整个帐户实体来执行此操作？

Answer 1

您可能忘记将新实体添加到上下文中。试试这个（未测试）：

bool isNew = false; 
var data = context.Accounts.Where(a => a.UserName == User.Identity.Name).Select(a => a.UserAddons).SingleOrDefault(); 

if (data == null) 
{ 
    data = new UserAddons(); 
    isNew = true; 
} 

// setting up properties of data 

if(isNew) 
    context.Add(data); 

context.SaveChanges(); 

Answer 2

如果我正确理解你的模型，你应该添加新UserAddons到Account

var account = context.Accounts.Where(a => a.UserName == User.Identity.Name).Single(); 

if (account.Addons == null) 
    account.UserAddons = new UserAddons(); 

{setting up properties of account.Addons} 

context.SaveChanges();