如何从c＃连接mysql？

Question

I downloaded mysql.dll . When I add this to my solution, I get an error like

Please make sure that file is accesssble and that it is a valid assembly or com component...

Please tell me how to connect to MySql from C# and any problems I may encounter while using MySql in C#. Will it run on every system?

Answer 1

http://www.mysql.com/downloads/connector/net/

You can download MySql connector and use it

Answer 2

you should reference MySql.Data.dll, not mysql.dll

To open database connection, you can use something like this

        internal static MySqlConnection GetConnection(string dbserver, string username, string password, string databasename)
    {
        try
        {
            MySqlConnection conn = new MySqlConnection("server=" + dbserver + ";User Id=" + username + ";Password=" + password + ";Persist Security Info=True;database=" + databasename);
            conn.Open();
            return conn;
        }
        catch (Exception ex)
        {
            // Code to handle exception
        }
    }

About supported platforms, the documentation says:

Connector/NET runs on any platform that supports the .NET framework. The .NET framework is primarily supported on recent versions of Microsoft Windows, and is supported on Linux through the Open Source Mono framework

Answer 3

First you have to Add MySQL.data.dll into References

Second, here is example code to connect to MySQL server and select a simple data from server

  private string _server; private string _port; private string _database; private string _uid; private string _pwd; //Constructor public MySQL() { Initialize(); } //Initialize connection string private void Initialize() { _server = "10.11.12.13"; _database = "ABCDEF"; _port = "3306"; _uid = "root"; _pwd = "raat"; var connectionString = "SERVER=" + _server + ";" + "DATABASE=" + _database + ";" + "PORT=" + _port + ";" + "UID=" + _uid + ";" + "PASSWORD=" + _pwd + ";";> connection = new MySqlConnection(connectionString); } //Connect to server private bool OpenConnection() { try { if (connection.State != System.Data.ConnectionState.Open) connection.Open(); return true; } catch (MySqlException ex) { //When handling errors, you can your application's response based //on the error number. //The two most common error numbers when connecting are as follows: //0: Cannot connect to server. //1045: Invalid user name and/or password. switch (ex.Number) { case 0: Global._logger.Info("Cannot connect to server. Contact administrator"); break; case 1045: Global._logger.Info("Invalid username/password, please try again"); break; } Global._logger.Info(ex.Message + " / " + ex.StackTrace); return false; } } //Close connection private bool CloseConnection() { try { if (connection.State != System.Data.ConnectionState.Closed) connection.Close(); return true; } catch (MySqlException e) { Global._logger.Info(e.Message + " / " + e.StackTrace); return false; } } //Create query to select data from Server public string GetStudentName(string studentId) { var query = "SELECT * FROM Student WHERE StudentID = '" + studentId; if (OpenConnection()) { //Create command var cmd = new MySqlCommand(query, connection); //Create data reader and excute datareader MySqlDataReader dataReader = null;> try { dataReader = cmd.ExecuteReader(); } catch (MySqlException mySQLEx) { Global._logger.Error(mySQLEx); } string studentName = ""; try { if (dataReader != null) { while (dataReader.Read()) { studentName= Convert.ToInt32(dataReader["Name"].ToString()); } dataReader.Close(); CloseConnection(); return studentName; } } catch (Exception e) { Global._logger.Info(e.Message + e.Source);> } } }