How to have a configurable connection string to SDE database?

[ShaningYu]

In my .Net project, I want to have a configurable connectionString, which is stores in a config file, to an enterprise SDE database.  The connectionString should be similar to the one below:
connectionString="Provider = Microsoft.Jet.OLEDB.4.0; Data Source=C:\...\myPGDB.mdb"
How to do it?  I haven't found any literature so far.

[ShaningYu · Accepted solution]

I will try the approach by ESRI Help:
http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#//0001000003s8000000
to open the workspace.