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.
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
i get the error
Unable to connect to any of the specified MySQL hosts
string conn_string = "Server=jelletaal.nl;Port=3306;Database=jelletaa_thepuckcup;Uid=jelletaa_jelle;Pwd = nP_9+hC_!_2E;";
MySqlConnectionStringBuilder connstring = new MySqlConnectionStringBuilder();
try
{
MySqlConnection conn = new MySqlConnection(conn_string);
conn.Open();
MessageBox.Show("succesfully created connection to database");
}
catch (MySql.Data.MySqlClient.MySqlException ex)
{
MessageBox.Show(ex.Message);
}
}
in my cpannel I have created a database called jelletaa_thepuckcup
I have created a user called jelletaa_jelle
with the password nP_9+hC_!_2E
the domain is jelletaal.nl
i have also granted my ip adress acces to the database
if anyone knows what i have to do tho get this working, please tell me.
I know that it is an easy problem but I can't find the error. I want to save data in my database. I create a database named "Examen" with Microsoft SQL Server 2008 then in my app in visual studio I make the connection string like this :
string connectionstring = #"Data Source=.\sqlexpress;Initial Catalog=Examen;Integrated Security=True";
Then I use this code to insert data into a "Test" table:
MySqlConnection connection = new MySqlConnection(connectionstring);
MySqlCommand cmd;
connection.Open();
try
{
cmd = connection.CreateCommand();
cmd.CommandText = "Insert into Examen.Test (nom,prenom) values (" + txbnom.Text + "," + txbprenom.Text + ") ";
cmd.ExecuteNonQuery();
MessageBox.Show("ok");
}
catch (Exception)
{
throw;
}
finally
{
if(connection.State == ConnectionState.Open)
{
connection.Close();
}
}
When running this code i had an error when openning the connection
Unable to connect to any of the specified MySQL hosts.
You are mixing MySQL and MSSQL.
Are you sure you want to connect to a MySQL server? Use http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlconnection(v=vs.110).aspx if you would like to connect to MSSQL.
Also you should make yourself familiar with SQL injection
I have a Windows XP machine used to create .Net applications with VS 2008.
I want to connect to a remote network server (using Windows xp) that is running an Oracle 10g database.
I am using the code below (with the first connection string) to connect directly to a version of 10g that is running on the same machine with no problems, however when I try to connect to the network machine, it actually crashes my application.
I have tried several variations of connection strings as I feel that I must be making a syntax error somewhere.
What concerns me is that I have dual try/catch statements in the application and I do not understand why it simply does not refuse the connection and report the error.
I suppose the real question is 'what is the correct syntax for the connection string'....or WHATEVER the hell I am doing wrong.
Any help or suggestions are greatly appreciated. Thank you in advance.
//Class Variables
string CONNSTR = "Server=192.168.0.1:1521;User ID=zahid;Password=abc123;";
public Oracle()
{
InitializeComponent();
}
//Methods
private void TestMyOracleConnection()
{
OracleConnection Conn = new OracleConnection(CONNSTR);
try
{
Conn.Open();
MessageBox.Show("Oracle Connection Established", "Success");
}
catch (OracleException ex)
{
MessageBox.Show(ex.Message, "Oracle Connection Failed!");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Oracle Connection Failed!");
}
finally
{
Conn.Close();
MessageBox.Show("Oracle Connection Closed", "Success");
}
}
private void buttonTestConnection_Click(object sender, EventArgs e)
{
TestMyOracleConnection();
}
You might want to try something like:
connection string:
Data Source=DBNAME;User ID=zahid;Password= abc123;Persist Security Info=True;Unicode=True;
Now look in the tnsname.ora file on your PC. It will be somewhere under your local Oracle Client installation. You're looking for something like:
DBNAME =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = OracleServerName)(PORT = 1510))
(ADDRESS = (PROTOCOL = TCP)(HOST = OracleServerName)(PORT = 1514))
)
(CONNECT_DATA =
(SERVICE_NAME = DBNAME)
)
)
You're looking to replace DBNAME and OracleServerName with your own. Don't forget, DBNAME is the name of the main database, not one of the schemas (the entity with all the tables and procedures, etc) under it.
Assuming you are using ODP.Net, you can try a connection string such as the following (taken from a web.config):
<add name="OdpConnection" connectionString="Data Source=xe;User Id=some_user;Password=some_password; Promotable Transaction=local"
providerName="Oracle.DataAccess.Client" />
You can read this connection string from the web.config in your code using something like this:
string connectionString = ConfigurationManager.ConnectionStrings["OdpConnection"].ConnectionString;
It's a good practice to avoid putting connection strings directly in code, since to change them requires a re-compile. By putting them in a config file, such as web.config or app.config, you can change them without having to re-compile your library or exe.
try
{
Conn.Open();
MessageBox.Show("Oracle Connection Established", "Success");
}
catch (OracleException ex)
{
MessageBox.Show(ex.Message, "Oracle Connection Failed!");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Oracle Connection Failed!");
}
finally
{
Conn.Close();
MessageBox.Show("Oracle Connection Closed", "Success");
}
You have pottential problem here: if conn.Open() fails (so connection is not opened) in finally you call conn.close(), but connection isn't opened - so it also fails, but it is now outside try catch. You need check for
if (Conn!=null && Conn.IsOpen())
Conn.Close();
Connection string for oracle:
Data Source=TORCL;User Id=myUsername;Password=myPassword;
Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID)));User Id=myUsername;Password=myPassword;
More here