Question

You can change the connection string at run-time like this. You make the connection string setting available for writing as a separate property inside the MySettings class:

Partial Friend NotInheritable Class MySettings     Public WriteOnly Property RunTimeConnectionString()         Set(ByVal value)             My.Settings('MyConnectionString') = value         End Set     End Property End Class 

Then, in some place when the application is being initialized (before using any table adapters of typed datasets), write something like:

My.Settings.RunTimeConnectionString = My.Settings.ProductionConnectionString 

Where ProductionConnectionString is a simple String setting. It is a User Scope setting so every user can change it (by assigning a value to it, similar to the code above) and save it by calling My.Settings.Save()

This code works well for connection strings which were initially created in the main project and stored in it’s settings (= app.config file).

The connection string in the app.config actually has a longer name: MyApp.MySettings.MyConnectionString.

When you have a connection string stored in the app.config in a class library project, and reference that project in the main project, the app.config files will somehow be merged, so the class library has it’s settings.

The thing that don’t know how to do, is change a setting from the class library at run-time. I could copy the connection string setting from the class library to the main project’s app.config. I must keep the same name, which looks something like: MyClassLibrary.My.MySettings.MyConnectionString.

Can the same principle I showed above be somehow applied to this second connection string?

Answer 1

I tested a little more, and found out that the same solution can be used inside a class library.

I made a new class (in the class library) with a shared (static) method like this:

Public Class MySettingsChanger     Public Shared Sub SetConnectionString(ByVal cnnString As String)         My.Settings.RunTimeConnectionString = cnnString     End Sub End Class 

And extended the MySettings class (in the class library) the same way as in the main project:

Namespace My     Partial Friend NotInheritable Class MySettings         Public WriteOnly Property RunTimeConnectionString()             Set(ByVal value)                 My.Settings('MyConnectionString') = value             End Set         End Property     End Class End Namespace 

At least it works in my case. The name of the connection in the main project and in the class library is the same only (the short name, not the whole ProjectNamespace.MySettings.ConnectionName). I haven’t tested with having a different name of the connection in the class library, but think it should not matter.