Question

更新旧软件，但为了保持向后兼容性，我需要连接到.mdb（访问）数据库。

我使用以下连接，但一直有异常，为什么？

我已经验证了路径，数据库存在等等，这一切都是正确的。

            string Server = "localhost";
            string Database = drive + "\\btc2\\state\\states.mdb";
            string Username = "";
            string Password = "Lhotse";

            string ConnectionString = "Data Source = " + Server + ";" +
                                      "Initial Catalog = " + Database + ";" + 
                                      "User Id = '';" + 
                                      "Password = " + Password + ";";

            SqlConnection SQLConnection = new SqlConnection();

            try
            {
                SQLConnection.ConnectionString = ConnectionString;
                SQLConnection.Open();
            }
            catch (Exception Ex)
            {
                // Try to close the connection
                if (SQLConnection != null)
                    SQLConnection.Dispose();

                //
                //can't connect
                //

                // Stop here
                return false;
            }

异常消息是：

建立与SQL Server的连接时发生与网络相关或特定于实例的错误。服务器未找到或无法访问。验证实例名称是否正确，以及SQL Server是否配置为允许远程连接。（提供者：命名管道提供程序，错误：40 - 无法打开与SQL Server的连接）

Answer 1

究竟是什么让您认为SQL Server连接（SqlConnection）愿意连接到MDB Access数据库？

如果您连接到Access，请使用OleDbConnection。对于Access连接字符串，请参阅http://www.connectionstrings.com/access

Answer 2

您需要在连接字符串中添加数据提供程序：

Provider = Microsoft.Jet.OLEDB.4.0; Data Source = C：\ mydatabase.mdb; User Id = admin; Password =;

Answer 3

使用using子句尝试这个更安全的版本...对于Database变量，使用System.IO.Path.Combine方法会更好更安全......：

            string Server = "localhost";
            string Database = System.IO.Path.Combine(@"C:\", @"\btc2\state\states.mdb");

            string Username = "";
            string Password = "Lhotse";

            string ConnectionString = "Data Source = " + Server + ";" +
                                      "Initial Catalog = " + Database + ";" + 
                                      "User Id = '';" + 
                                      "Password = " + Password + ";";
            bool bDatabaseOk = false;
            using (SqlConnection SQLConnection = new SqlConnection()){

                try
                {
                    SQLConnection.ConnectionString = ConnectionString;
                    SQLConnection.Open();
                    bDatabaseOk = true;
                }
                catch (SqlException Ex)
                {
                   // Handle the SqlException here....
                   //
                   //can't connect
                    bDatabaseOk = false;
                }
            } 
            return bDatabaseOk;

SQLConnection.Open（）;抛出异常

3 个答案: