mongodb连接不上

用mongovue连接时显示：

提示框里的代码如下：

Connection was refused
Unable to connect to server 127.0.0.1:27017: 由于目标计算机积极拒绝，无法连接。 127.0.0.1:27017.
Type: MongoDB.Driver.MongoConnectionException
Stack:    at MongoDB.Driver.Internal.DirectMongoServerProxy.Connect(TimeSpan timeout, ReadPreference readPreference)
   at MongoDB.Driver.MongoServer.Connect(TimeSpan timeout)
   at MongoDB.Driver.MongoServer.Connect()
   at MangoUI.MMongo.Open(Boolean mustWrite)
   at MangoUI.MMongo.Open()
   at MangoUI.MConnection.get_IsValid()
   at MangoUI.WinConnect.btnTest_Click(Object sender, EventArgs e)


由于目标计算机积极拒绝，无法连接。 127.0.0.1:27017
Type: System.Net.Sockets.SocketException
Stack:    at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
   at System.Net.Sockets.TcpClient.Connect(IPEndPoint remoteEP)
   at MongoDB.Driver.Internal.MongoConnection.Open()
   at MongoDB.Driver.Internal.MongoConnection.GetNetworkStream()
   at MongoDB.Driver.Internal.MongoConnection.SendMessage(BsonBuffer buffer, Int32 requestId)
   at MongoDB.Driver.Internal.MongoConnection.SendMessage(MongoRequestMessage message)
   at MongoDB.Driver.Operations.CommandOperation`1.Execute(MongoConnection connection)
   at MongoDB.Driver.MongoServerInstance.RunCommandAs[TCommandResult](MongoConnection connection, String databaseName, IMongoCommand command)
   at MongoDB.Driver.MongoServerInstance.Ping(MongoConnection connection)
   at MongoDB.Driver.MongoServerInstance.Connect()
   at MongoDB.Driver.Internal.DirectMongoServerProxy.Connect(TimeSpan timeout, ReadPreference readPreference)