I've been trying to make a connection with my SQL Server database (Mynewdatabase) using the default connection string that was generated (supposedly) when I added the data source for this project. However, I'm thus far unable to make a connection: I'm getting an error that "the server was not found or was not accessible".
This my code. Thanks so much for any help you can offer:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;
namespace Parsevcf2sql
{
class Program
{
static void Main(string[] args)
{
// here is where I get what I believe is an appropriate connection string
string cs = Parsevcf2sql.Properties.Settings.Default.MynewdatabaseConnectionString;
SqlConnection myconnection = new SqlConnection(cs);
Console.WriteLine(cs);
try
{
myconnection.Open();
Console.WriteLine("This worked!");
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
}
This might help you out, change localhost to your address and database name as well.. But Please check sql server must be in running mode
{
// connection string!
SqlConnection myConn = new SqlConnection("Server=localhost\\SQLEXPRESS;Integrated security=SSPI;database=Mynewdatabase;");
try
{
myConn.Open();
Console.WriteLine(myConn );
}
catch (System.Exception)
{
// some exception
}
finally
{
if (myConn.State == ConnectionState.Open)
{
myConn.Close();
}
myConn.Dispose();
}
}
or check out this tutorial
Related
I'm trying to connect to my mysql database (I'm hosted by infinityfree.net), entering these credentials:
connection = new MySqlConnection("Server=sql306.epizy.com; Port=3306; Database=epiz_27674946_db1; Uid=epiz_27674946; Pwd=**********; ");
But I get this exception:
Unable to connect to any of the specified mysql hosts
I don't know why this happens, the credentials should be right...
Can you help me?
Full code:
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 sharetru
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
MySqlConnection connection;
private void Form1_Load(object sender, EventArgs e)
{
try
{
connection = new MySqlConnection("Server=sql306.epizy.com; Port=3306; Database=epiz_27674946_db1; Uid=epiz_27674946; Pwd=*******; ");
connection.Open();
if (connection.State == ConnectionState.Open)
{
label1.Text = "Connected";
label1.ForeColor = Color.Green;
}
else
{
label1.Text = "Not Connected";
label1.ForeColor = Color.Red;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}
Regarding this service (infinityfree) it is not possible to access mysql from desktop applications (outside the infinityfree host)
https://support.infinityfree.net/mysql/how-to-connect-with-mysql/
The code looks correct. The issue probably is in the connection string details.
Are you able to connect using the following connection details via some GUI tool?
Workbench for example https://dev.mysql.com/downloads/workbench/
I am trying to create a project that will read, write,and check for duplicates in my access data base file. I am using C# and keep getting "Connection failed error that I have written into the program if the connection state = 0. If anyone can offer any help I would appreciate it. I am using Access 2016 and I am not sure what references I need for my project (if any). Everything I have found online is either outdated or doesn't work.
Thank you!
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 System.Threading;
using System.Net;
using System.IO;
using System.Data.OleDb;
namespace RHG
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
using (OleDbConnection connection = new OleDbConnection(#"Provider=Microsoft.ACE.OLEDB.16.0;Data Source=C:\Users\grosales\Documents\rhg\RHG\Used.accdb"))
{
try
{
connection.Open();
MessageBox.Show("connected");
}
catch (Exception ex)
{
MessageBox.Show("connection failed");
}
}
}
`
You have not opened the connection.
connection.Open();
Note: Checking the connection state is not enough. You might get an exception when trying to open the connection. Enclose it in try-catch instead.
It is also a good practice to enclose work on a connection with using
using (var connection = new OleDbConnection()) {
connection.ConnectionString =
#"Provider=Microsoft.ACE.OLEDB.16.0;Data Source=C:\Users\...\Used.accdb";
try {
connection.Open();
//TODO: do something with the connection
} catch (Exception ex) {
MessageBox.Show("Connection Failed\r\n\r\n" + ex.Message);
}
}
This ensures that the connection will be closed and the resources be released.
Try following the examples here: https://msdn.microsoft.com/en-us/library/system.data.oledb.oledbconnection(v=vs.110).aspx
You're missing the connection.Open(); statement, which should be wrapped in a try catch.
Additionally, you can specify the connection string within the constructor, like
using (OleDbConnection connection = new OleDbConnection(#"Provider=Microsoft.ACE.OLEDB.16.0;Data Source=C:\Users\grosales\Documents\rhg\RHG\Used.accdb"))
{
//do DB access here
}
//no need to call connection.Close() - it's automatically done once you leave the using block.
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.
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.
I am trying to connect to an SQL db to extract data and I am using Dapper for the process. I assume I am having some problems with the connection string; I am trying to access a remote sql server 2012 db but my connection keeps failing:
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Dapper;
using System.Data.SqlClient;
namespace Data_Connection
{
public static class Program
{
static void Main(string[] args)
{
string connetionString = null;
SqlConnection cnn ;
connetionString = "Server=datanet.local.net/datadb; Database=ddata;Trusted_Connection=True";
cnn = new SqlConnection(connetionString);
try
{
cnn.Open();
Console.WriteLine("Connection Open !");
cnn.Close();
}
catch (Exception ex)
{
Console.WriteLine("Can not open connection !");
}
}
}
}
I have never tried connecting to an sql db using c# and I am fairly new to the environment. Any help would be appreciated
Thanks!
I have installed the MySQL server using XAMMP.Created a new database with some data using phpmyadmin.Then i tried to connect to database using this code.But it did not connect.It shows me an error.
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SqlClient;
namespace TestConsole
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Testing!");
SqlConnection myco = new SqlConnection("server=localhost;User Id=root;database=customer;Trusted_Connection=yes");
try
{
myco.Open();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.ReadKey();
}
}
}
Error:
http://pastebin.com/MyEtk4w6
You have MySql then you need to use the classes for MySql not the ones used for SqlServer
MySqlConnection myco = new MySqlConnection("Server=localhost;Database=customer;" +
"Uid=username;Pwd=password;");
Also the connection string for MySql is different
Server=localhost;Database=customer;Uid=username;Pwd=password;
The connection strings for MySql could be very numerous, you should check the correct one for your requirement here at connectionstrings.com
It's because you're using a SqlConnection object which is for Microsoft SQL Server.
Use a MySQLConnection instead.