ネット上ではC#でのやり方が多かったのでVB.net版で載せます。
Imports Npgsql '忘れずに '接続文字列は適当に変更してください。 Dim builder As New Npgsql.NpgsqlConnectionStringBuilder With builder .Host = "192.xxx.xxx.xxx" .Database = "dbname" .Username = "username" .Password = "password" .Port = 5432 .Timeout = 20 End With Dim conn As NpgsqlConnection = New NpgsqlConnection(builder.ConnectionString) conn.Open() Dim command As NpgsqlCommand = New NpgsqlCommand("select * from test", conn) Dim dr As NpgsqlDataReader dr = command.ExecuteReader() If dr.HasRows Then MessageBox.Show("hasrows is true") End If While (dr.Read()) MessageBox.Show(dr(0)) End While conn.Close()