Develop Reference

How to connect to mysql with computer name in C#

I want to connect to mysql with my computer name as host.
I get this error :
unable to connect to any of the specified mysql hosts
When i change the host with localhost or 127.0.0.1. it's work fine.
I test the connection directly in mysql workbench with my computer name : COMP-18TN. MySQL Workbench could connect to that server. But not my c# code.
You find as bellow my code :
string host = "COMP-18TN";
string DatabaseName = "Cars_DB";
string UserName ="root_name";
string Password ="pass";
string connString = string.Format("Server={0}; database={1}; UID={2}; password={3}",
host, DatabaseName, UserName, Password);
MySqlConnection conn = new MySqlConnection(connString);
try
{
conn.Open();
}
catch (Exception e)
{
MessageBox.Show(e.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

You can try adding an entry in your hosts file located in C:\Windows\System32\drivers\etc\hosts:
127.0.0.1 COMP-18TN
This way your computer name will resolve to the local IP which you know works.

WinFormApp won't connect to the database

No clue why this won't work. It has worked before.
I do have the connection string in the app.config as well. I get the MySqlException error saying unable to connect to any database.
I made sure the firewall wasn't stopping it and I opened the ports on my router. All the references are in place too. This should work.
string connString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;
try
{
using (MySqlConnection Conn = new MySqlConnection(connString))
Conn.Open();
MessageBox.Show("DB Connected");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
MessageBox.Show(ex.Message);
}

try this code
string connetionString = null;
MySqlConnection cnn ;
connetionString = "server=localhost;database=testDB;uid=root;pwd=abc123;";
cnn = new MySqlConnection(connetionString);
try
{
cnn.Open();
MessageBox.Show ("Connection Open ! ");
cnn.Close();
}
catch (Exception ex)
{
MessageBox.Show("Can not open connection ! ");
}

MySQL Databases cannot be used in WinFormApp due to security risks on a remote server. MS SQL DB's are supported. I didn't know that and I see a lot of questions about this so if anyone can't connect this may be why.

Connection string for local database not working

I have a database on my local machine on SQL Server Management studio.
The database connection information is as follows.
In my c# application, I have a connection string to connect to this database. I get an error though saying my connection string is incorrect. I have tried a number of different ones.
This is my function to connect to a database.
public virtual void openConnection()
{
con = new SqlConnection();
con.ConnectionString = "Server=DESKTOP-8UDMQUI\\WILLIAMSQL;Initial Catalog=team3db;TrustServerCertificate=true;";
try
{
con.Open();
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
}
I have two \ in the server name because when I only have one, it has a red squiggle line under it throwing me an error on visual studio.
What should my connection string be? Note there is no password on this database.

Replace TrustServerCertificate = true; with Integrated Security = true

Connect and insert data from my computer to server's MySQL DB table with the help of C#.NET

I want to connect with a server's MySql DB(cpanel) . Though there are no errors every time I'm getting a message for Messegebox : unable to connect to any of the specified any of the MySql hosts.
using MySql.Data.MySqlClient;
connString = "SERVER = ********;PORT=3306;DATABASE=********;UID=**********;PASSWORD=*********";
try
{
conn = new MySqlConnection();
conn.ConnectionString = connString;
conn.Open();
MessageBox.Show("Server is online");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{ MessageBox.Show(ex.Message);}

If you try to connect to your MySQL server externally, external connections need to be enabled.
Be aware that it is a security hole if you provide your app to others which contain the DB information. To go around that, you need to create a Web-API.

The first step to connect to your app to a remote server MySql Server is verify if it allows external connections, for default the root user is locked, to allow local you can try to connect with the root user typing the following command in MySql:
GRANT ALL PRIVILEGES ON *.* TO 'root'#'%' IDENTIFIED BY 'password' WITH GRANT OPTION;
FLUSH PRIVILEGES;
'root': You can change it with your user.
'%': allows all connections, you can limit it typing an IP.
Second step is verify your MySql .net connector
Cheers!

I would look into using ConnectionStringBuilder. Also note the use of 'using'. This will ensure resources are disposed once finished with.
private MySqlConnectionStringBuilder sConnString = new MySqlConnectionStringBuilder
{
Server = "",
UserID = "",
Password = "",
Database = ""
};
private void Test(){
// open connection to db
using (MySqlConnection conn = new MySqlConnection(sConnString.ToString()))
{
using (MySqlCommand cmd = conn.CreateCommand())
{
try
{
conn.Open();
cmd.CommandText = "SELECT * FROM foo WHERE OrderID = #OrderID";
// Add any params
cmd.Parameters.AddWithValue("#OrderID", "1111");
cmd.Prepare();
cmd.ExecuteNonQuery();
}
catch (Exception e)
{
MessageBox.Show(e.ToString());
return;
}
}
}
}

Issue connecting to gearhost database

I'm trying to connect with C# code to a SQL Server database hosted on gear host using the System.Data.SqlClient library, but it doesn't work, I get an error "Server does not exist or connection refused."
Maybe I need do install some driver? Or is there anything wrong with my code?
string connetionString = "Data Source=mssql.gear.host:1433;Initial Catalog=databasename;User ID=userid;Password=mypassword";
SqlConnection cnn = new SqlConnection(connetionString);
try
{
cnn.Open();
Console.WriteLine("Connection Open!");
cnn.Close();
}
catch (Exception ex)
{
Console.WriteLine(ex);
}

when removing the port it works ,obviously the database in gear host doesn't use a port