In C# WinForms, where should I put my SQL connection string variable if I want to access it all over my application?
Right now I'm copy-pasting it wherever I'm using it.
//Sql connection string
SqlConnection con = new SqlConnection(@"Data Source=" + globalvariables.hosttxt + "," + globalvariables.porttxt + "\\SQLEXPRESS;Database=ha;Persist Security Info=false; UID='" + globalvariables.user + "' ; PWD='" + globalvariables.psw + "'");
SqlCommand command = con.CreateCommand();
You can simply use the app.config (or web.config) for that. It has a special section for connection-strings. See the MSDN-article about that. Then you can retrieve the string in code as use1515791 has already pointed out, like this:
ConfigurationManager.ConnectionStrings["NameOfConnectionStringInConfig"].ConnectionString
I rather not using app.config file, because it's not secure and hackable easily (every connection info is stored in plain text format here).
If I'm not using any of my DLLs, I place the SqlConnection in Program.cs with public getter and disabled setter. I make all the initializations in Program.cs, so it looks something like this:
static class Program
{
private static SqlConnection con;
internal static SqlConnection Con
{
get
{
return con = new SqlConnection(@"Data Source=" + globalvariables.hosttxt + "," + globalvariables.porttxt + "\\SQLEXPRESS;Database=ha;Persist Security Info=false; UID='" + globalvariables.user + "' ; PWD='" + globalvariables.psw + "'");
}
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
Now can access it (for example) from you Form1.cs:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
SqlCommand cmd = new SqlCommand();
cmd.Connection = Program.Con;
}
}
I've created a DLL to connect to SQL easily, check it here if you're interested.
Thats a rather general question imo.. depends on the application structure and so on. I tend to use a class "ApplicationContext" with properties for such things. However, maybe
ConfigurationManager.ConnectionStrings["whatever"].ConnectionString
is used a lot i think (add reference to System.Configuration)
Btw, if you use it "all over the place", don't you need an adapter class instead?
EDIT
public class DataAcces
{
private string Connectionstr;
public DataAcces()
{
this.Connectionstr = ConfigurationManager.ConnectionStrings["whatever"].ConnectionString;
}
public object ReturnSomething()
{
using(SqlConnection con = new SqlConnection(this.Connectionstr))
{
//do stuff to db and return something
}
}
}
and then when you need it
....
{
var whatYouNeed = (new DataAcces()).ReturnSomething();
}
typos happen :) this is the easiest to use i can come up with, not the best.
