我正在使用.NET Core 2.0
我有 3 种型号:
class ModelA {
[Key]
public int ID { get; set; }
public List<ModelB> Emails { get; set; }
}
class ModelB {
[Key]
public int ID { get; set; }
public string Name { get; set; }
public int RequestId { get; set; }
public ModelA Request { get; set; }
public List<ModelC> Tokens { get; set; }
}
class ModelC {
[Key]
public int ID { get; set; }
public string Token { get; set; }
public int Status { get; set; }
public string getStatusName()
{
string[] Statuses = new string[] {
"Created", // 0
"Approved", // 1
"Rejected" // 2
};
return Statuses[Status];
}
}
我确实也有这样的上下文:
public class RequestorContext : DbContext
{
public DbSet<ModelA> Request { get; set; }
public DbSet<ModelB> Email { get; set; }
public DbSet<ModelC> Token { get; set; }
public RequestorContext(DbContextOptions<RequestorContext> options) : base(options)
{
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}
}
现在我想在控制器中做这样的事情:
var request = await _context.Request
.Include(r => r.Emails) //also include tokens - how ???
.SingleOrDefaultAsync(r => r.Id == id);
那么基本上如何在电子邮件中包含相应的令牌?为了能够在视图中做这样的事情:
@foreach (var email in Model.Emails)
{
<tr>
<td>@email.Name</td>
<td>@email.Token.Token</td>
<td>@email.Token.getStatusName()</td>
</tr>
}
目前我收到这样的错误:
运行时绑定器异常:无法对空值执行运行时绑定 reference CallSite.Target(Closure , CallSite , object ( System.Dynamic.UpdateDelegates.UpdateAndExecute1(CallSite 站点,T0 arg0( AspNetCore._Views_Requestor_Details_cshtml+d__8.MoveNext(( in Details.cshtml + @email。Token.getStatusName((
要加载多个级别的相关数据,请使用此处所述的ThenInclude
。
为了解决您的问题,您的代码如下所示:
var request = await _context.Request
.Include(r => r.Emails)
.ThenInclude(e => e.Tokens)
.SingleOrDefaultAsync(r => r.Id == id);