Connection keeps closing in VS2005 Report Designer

I'm trying to design a report in VS2005 BIDS Report Designer, but every so often, I haven't figured out any regular action that might cause it, but when I try and run the query, I get the following error:

An error occurred while retrieving the parameters in the query. DeriveParameters requires an open and available Connection. The connection's current state is closed

What causes th开发者_如何学JAVAis and what can I do to open the connection again?

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Having searched the interwbes for this same problem, the answer validated on my part, is to close and reopen the Visual Studio solution.