Question

还有其他类似的问题，但与我所知道的实际FindAsync无关。

我的ClientsController调用ClientService.GetClients，它使用mongo驱动程序在Azure上查询mongodb。

单步执行调试器，它会升到我调用clientCollection.FindAsync的位置。如果我跳过这一行，那么下面的行永远不会被击中而且没有给出错误。就像等待的任务永远不会回来一样。

public async Task<List<Client>> GetClients(SearchRequestDTO searchRequest)
{
  var response = new List<Client>();

  var db = _databaseUtilityService.GetCoreDatabase();
  var clientCollection = db.GetCollection<Client>(Properties.Settings.Default.ClientCollectionName);

  var cursor = await clientCollection.FindAsync(new BsonDocument());

  while (await cursor.MoveNextAsync())
  {
    response.Concat(cursor.Current.ToList());
  }

  return response;
}

调试器永远不会越过var cursor = ...行的原因是什么？

编辑 -

我可以改为Result -

var cursor = clientCollection.FindAsync(new BsonDocument()).Result;

但我不确定这是我想做的事。

public async Task<List<Client>> GetClients(SearchRequestDTO searchRequest)
{
  var db = _databaseUtilityService.GetCoreDatabase();
  var clientCollection = db.GetCollection<Client>(Properties.Settings.Default.ClientCollectionName);
  var results = clientCollection.FindAsync(new BsonDocument()).Result;

  return results.ToList();
}

Answer 1

由于没有太多关于上下文的信息，所以我提出了模拟类来满足问题。

请参阅下面的重载方法，在调用时，它将始终返回三个记录的列表。现在您的代码出了什么问题？我相信它在你的while循环中。您正在调用导致问题的response.AddRange。我改为呼叫public async Task<List<Client>> GetClients() { var mongoUri = "mongodb://localhost:27017"; var mongoClient = new MongoClient(mongoUri); var mongoDatabase = mongoClient.GetDatabase("ClientDB"); var clientCollection = mongoDatabase.GetCollection<Client>("Clients"); // Empty collection to always get accurate result. clientCollection.DeleteMany(new BsonDocument()); // Insert some dummy data clientCollection.InsertOne(new Client() {Address = "One street, some state", ZipCode = 11111}); clientCollection.InsertOne(new Client() { Address = "2nd street, some state", ZipCode = 22222 }); clientCollection.InsertOne(new Client() { Address = "Third street, some state", ZipCode = 33333 }); var response = new List<Client>(); var cursor = await clientCollection.FindAsync(new BsonDocument()); while (await cursor.MoveNextAsync()) { response.AddRange(cursor.Current); } return response; }而且有效。

#!/bin/bash

read -p "Number of Adult Tickets:(0 for none) " integer1    
read -p "Number of Junior Tickets:(0 for none) " integer2

echo ""    
echo "$integer1 Adults"    
echo "$integer2 Juniors"
echo ""

num1=$50    
num2=$20    
num3=$5    

echo "Season Pass Add-On:"    
echo "1)Add Seasonal Parking"    
echo "2)Add Season Pass For Theme Park"    
echo "7)Just Buy Tickets For Today"    
echo "8)I wanna exit."

echo ""
read -p "What would the guest like to do? " guest
echo ""    

case $guest in
    1)     
       echo "Add Seasonal Parking"     
       echo ""     
       echo "Add an additional $num1 for every adult pass"     
       echo ""      
       echo "For Adult Tickets "$(( integer1 + num1 ))""      
       echo "For Junior Tickets "$(( integer2 + num1 ))""     
       ;;    
    2)     
       echo "Add Season Pass For Theme Park"     
       echo ""     
       echo "Add an additional $num2 for every adult pass"     
       echo "Add an additional $num3 for every junior pass"     
       echo ""      
       echo "For Junior Tickets "$(( integer2 * num2 ))""      
       echo "For Adult Tickets "$(( integer1 * num3 ))""      
       echo "For Junior Tickets "$(( integer2 * num2 ))""      
       echo "For Adult Tickets "$(( integer1 * num3))""    
       ;; 
    3)     
       echo "Just buy tickets for today"     
       exit 0     
       ;;    
    4)     
       echo "invalid entry. You are exiting"     
       exit 1    
       ;; 
esac     

exit 0

C＃MongoDB FindAsync永远不会在Await上返回

1 个答案: