c# - 使用 Entity Framework 模型插入数据

Question

我正在尝试使用 Entity Framework 模型在我的数据库中插入一些数据，但由于某些我不知道的原因，它什么也没做。

我是不是漏掉了什么？

using (var context = new DatabaseEntities())
{
    var t = new test
    {
        ID = Guid.NewGuid(),
        name = "blah",
    };
    context.AddTotest(t);
    context.SaveChanges();
}

Answer 1

应该是:

context.TableName.AddObject(TableEntityInstance);

地点:

1. TableName:数据库中表的名称。
2. TableEntityInstance:表实体类的一个实例。

如果您的表是Orders，那么:

Order order = new Order();
context.Orders.AddObject(order);

例如:

 var id = Guid.NewGuid();
    
 // insert
 using (var db = new EfContext("name=EfSample"))
 {
    var customers = db.Set<Customer>();
    customers.Add( new Customer { CustomerId = id, Name = "John Doe" } );
  
    db.SaveChanges();
 }

这是一个例子:

public void UpdatePlayerScreen(byte[] imageBytes, string installationKey)
{
  var player = (from p in this.ObjectContext.Players where p.InstallationKey == installationKey select p).FirstOrDefault();

  var current = (from d in this.ObjectContext.Screenshots where d.PlayerID == player.ID select d).FirstOrDefault();

  if (current != null)
  {
    current.Screen = imageBytes;
    current.Refreshed = DateTime.Now;

    this.ObjectContext.SaveChanges();
  }
  else
  {
    Screenshot screenshot = new Screenshot();

    screenshot.ID = Guid.NewGuid();
    screenshot.Interval = 1000;
    screenshot.IsTurnedOn = true;
    screenshot.PlayerID = player.ID;
    screenshot.Refreshed = DateTime.Now;
    screenshot.Screen = imageBytes;

    this.ObjectContext.Screenshots.AddObject(screenshot);
    this.ObjectContext.SaveChanges();
  }
}