We have an ASP .NET (MVC) app and are using Entity Framework 6 to connect to our databases. The DbContext is constructed in a standard way and it loads the connection string
If you have this line in web.connfig
Add this in azure portal:
Name Column => Entities
Value Column => metadata=res://*/TestDB.csdl|res://*/TestDB.ssdl|res://*/TestDB.msl;provider=System.Data.SqlClient;provider connection string="Data Source=XXXXXXXX.database.windows.net,1433;Initial Catalog=YourDB;User ID=YourUser;Password=XXXXXX"
"Custom" - In the drop selection box
Make sure (as stated in first answer) to replace " with "