// This example needs the
// System.Data.SqlClient library

#region Building the connection string

string Server = "localhost";
string Username = "my_username";
string Password = "my_password";
string Database = "my_database";

string ConnectionString = "Data Source=" + Server + ";";
ConnectionString += "User ID=" + Username + ";";
ConnectionString += "Password=" + Password + ";";
ConnectionString += "Initial Catalog=" + Database;

#endregion


#region Try to establish a connection to the database

SqlConnection SQLConnection = new SqlConnection();

try
{
SQLConnection.ConnectionString = ConnectionString;
SQLConnection.Open();

// You can get the server version
// SQLConnection.ServerVersion
}
catch (Exception Ex)
{
// Try to close the connection
if (SQLConnection != null)
SQLConnection.Dispose();

// Create a (useful) error message
string ErrorMessage = "A error occurred while trying to connect to the server.";
ErrorMessage += Environment.NewLine;
ErrorMessage += Environment.NewLine;
ErrorMessage += Ex.Message;

// Show error message (this = the parent Form object)
MessageBox.Show(this, ErrorMessage, "Connection error", MessageBoxButtons.OK, MessageBoxIcon.Error);

// Stop here
return;
}

#endregion