Is it possible to reference a connection string in another connection string?

问题

We have a project with multiple DLLs. In each DLL, we connect to a database - always the same one for a client.

As a result, we now have 3 near-identical connection strings : one for our web site, one for ado.net, and one for telerik reporting :

    <add name="BDConnectionString" connectionString="Data Source=localhost;Initial Catalog=DATABASE;Persist Security Info=True;User ID=USER;Password=PASSWORD; MultipleActiveResultSets=True;Pooling=True;Max Pool Size=500;" providerName="System.Data.SqlClient" />
    <add name="CMS.Reporting.My.MySettings.BDConnectionString" connectionString="Data Source=localhost;Initial Catalog=DATABASE;Persist Security Info=True;User ID=USER;Password=PASSWORD" providerName="System.Data.SqlClient" />
    <add name="KOPWebEntities" connectionString="metadata=res://*/Data.web.csdl|res://*/Data.web.ssdl|res://*/Data.web.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=localhost;Initial Catalog=DATABASE;Persist Security Info=True;User ID=USER;Password=PASSWORD;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" />

Now it's still manageable, but in the future, we will have more ADO.Net Entity Framework connections, so maybe 10 connection strings by client ?

Is there a way to say, "ok, for this connection string, use the value coming from here" instead of duplicating it ? At least for ADO.Net ?

Or is there a better way ?

Thanks

回答1:

I noticed you mentioned Entity Framework. It is possible to create entity contexts with different SQL connections than the one defined in the application/web config. (I'd have to dig up the code). However, as far as the more general "have a connection string that actually references another connection string" question, I'd say, if you don't have the source, tough luck.

It'd probably be better if your DLLs didn't reference app/web config settings and, for the classes defined in there, you could pass in either the, the "application key" which has an associated value referencing a connection string, the SQL connection string itself, a SqlConnection instance, or some SqlConnection-Factory-Thing you make up.

来源：https://stackoverflow.com/questions/6443060/is-it-possible-to-reference-a-connection-string-in-another-connection-string