我在 c# 中有一个简单的应用程序：
NpgsqlConnection conn = new NpgsqlConnection("Server=127.0.0.1;Port=5432;User Id=joedata;Password=joedata;Database=joedata;");
conn.Open();
conn.Close();
使用以下信息在 conn.Open() 的调试模式下引发异常：
Npgsql.NpgsqlException: Failed to establish a connection to '127.0.0.1'. ---> System.Exception: Failed to establish a connection to '127.0.0.1'.
at Npgsql.NpgsqlClosedState.Open (Npgsql.NpgsqlConnector context) [0x00101] in /Users/fxjr/Desenvolvimento/ProjetosOpenSource/Npgsql/NpgsqlSourceRelease/Npgsql2/src/Npgsql/NpgsqlClosedState.cs:171
--- End of inner exception stack trace ---
at Npgsql.NpgsqlClosedState.Open (Npgsql.NpgsqlConnector context) [0x00264] in /Users/fxjr/Desenvolvimento/ProjetosOpenSource/Npgsql/NpgsqlSourceRelease/Npgsql2/src/Npgsql/NpgsqlClosedState.cs:232
at Npgsql.NpgsqlConnector.Open () [0x00039] in /Users/fxjr/Desenvolvimento/ProjetosOpenSource/Npgsql/NpgsqlSourceRelease/Npgsql2/src/Npgsql/NpgsqlConnector.cs:685
at Npgsql.NpgsqlConnectorPool.GetPooledConnector (Npgsql.NpgsqlConnection Connection) [0x00169] in /Users/fxjr/Desenvolvimento/ProjetosOpenSource/Npgsql/NpgsqlSourceRelease/Npgsql2/src/Npgsql/NpgsqlConnectorPool.cs:434
此错误仅在调试模式下发生（带断点）。请帮忙。
我正在使用：
MonoDevelop v3.0.5
Npgsql2.0.12-bin-mono2.0
mono 2.10.9 for Windows