Winforms - Replace a ConnectionString at runtime

Question

Hi,

I'd like to allow my user's to switch between different databases on the login page at runtime.

I've currently got the ConnectionString stored in my App Settings file and all the dataset's refer to this setting.

I have tried modifying this setting at runtime, but this seems impossible.

How is the best way to do this?

Thanks,

Answer 1

Could you not just have a second connection string in your config file? What sort of data access code have you got setup?

Answer 2

You can force the code to pick up the connection string from disk by calling ConfigurationManager.RefreshSection prior to fetching the connection string:

ConfigurationManager.RefreshSection("connectionStrings");
string connectionString = ConfigurationManager.ConnectionStrings["someConnection"].ConnectionString;

Answer 3

Is the database encrypted?

If it's not something that requires a large amount of privacy, you can store the connection string on a per-user basis.

For example:

System.Properties.Default.MyConnectionString = "Blah";
System.Properties.Default.Save();

or

string myConnectionString = System.Properties.Default.MyConnectionString;

EDIT: These can originally be set in VS by going to Project -> Properties -> Settings and make sure you put them in "User" Scope (Application Scope is read-only during runtime unless I'm mistaken).

EDIT2: Regarding comment below:

SqlConnection myConnection = new SqlConnection();
//Set from a normal String saved in user's settings
myConnection.ConnectionString = System.Properties.Default.MyConnectionString; 
myConnection.Open();