Because connecting to an external server is unpredictable, it is
important to add error handling to your .NET application. When
there is an error connecting, the
MySqlConnection
class will return a
MySqlException
object. This object has two
properties that are of interest when handling errors:
Message
: A message that describes the current exception.Number
: The MySQL error number.
When handling errors, you can adapt the response of your application 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, user password, or both.
The following code example shows how to manage the response of an application based on the actual error:
C# Example
Press CTRL+C to copyMySql.Data.MySqlClient.MySqlConnection conn; string myConnectionString; myConnectionString = "server=127.0.0.1;uid=root;" + "pwd=12345;database=test"; try { conn = new MySql.Data.MySqlClient.MySqlConnection(myConnectionString); conn.Open(); } catch (MySql.Data.MySqlClient.MySqlException ex) { switch (ex.Number) { case 0: MessageBox.Show("Cannot connect to server. Contact administrator"); break; case 1045: MessageBox.Show("Invalid username/password, please try again"); break; } }
Visual Basic Example
Press CTRL+C to copyDim myConnectionString as String myConnectionString = "server=127.0.0.1;" _ & "uid=root;" _ & "pwd=12345;" _ & "database=test" Try Dim conn As New MySql.Data.MySqlClient.MySqlConnection(myConnectionString) conn.Open() Catch ex As MySql.Data.MySqlClient.MySqlException Select Case ex.Number Case 0 MessageBox.Show("Cannot connect to server. Contact administrator") Case 1045 MessageBox.Show("Invalid username/password, please try again") End Select End Try
If you are using multilanguage databases then you must specify
the character set in the connection string. If you do not
specify the character set, the connection defaults to the
latin1
character set. You can specify the
character set as part of the connection string, for example:
Press CTRL+C to copyMySqlConnection myConnection = new MySqlConnection("server=127.0.0.1;uid=root;" + "pwd=12345;database=test;Charset=latin1");