CODEWITHSUNDEEP
c#mysql
Ali Shaikh
Ali Shaikh

Reputation: 121

Handle MySQL exceptions in Visual Studio

The following code checks if I can connect to the MySQL database or not. It is working fine when it connects but when it can't connect it throws out an error instead of executing the 'Else' statement

    using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using MySql.Data.MySqlClient;

namespace MySQLConnection
{
    public partial class FrmConnection : Form
    {
        public FrmConnection()
        {
            InitializeComponent();
        }

        string connectionString = "host=192.168.0.91; database=c#1; user=test1; password=test1";
        private void button1_Click(object sender, EventArgs e)
        {
            using (MySqlConnection con= new MySqlConnection(connectionString))
            {
                con.Open();
                if(con.State==ConnectionState.Open)
                {
                    label1.Text = "Connection Established!";
                }
                else
                {
                    label1.Text = "Connection Error!";
                }
            }
        }
    }
}

I get this error

An unhandled exception of type 'MySql.Data.MySqlClient.MySqlException' occurred in MySql.Data.dll

Additional information: Unable to connect to any of the specified MySQL hosts.

Upvotes: 0

Views: 7968

Answers (1)

Phiter
Phiter

Reputation: 14982

To handle exceptions, you can do this:

using (MySqlConnection con= new MySqlConnection(connectionString))
    {
        try
        {
            con.Open();
            label1.Text = "Connection Established!";
        }
        catch(Exception ex)
        {
            label1.Text = "Connection Error!\n"+ex.Message;
        }
        finally
        {
            con.Close();
        }
    }

It's pretty explained: It will try to open the connection and set a success message.
If it fails, it will say that the connection failed and display the error message from the catched exception.
Then, on the finally block, it will close the connection, after both try and catch has finished executing.

I'm not sure but since you're using using, you wouldn't need the finally block, for the using function will close the connection automatically.

More info on the MSDN page for the try catch finally blocks.

Upvotes: 1

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