How to Write to A Directory From Visual Basic, First Making the Directory Path, Then Adding the file Name to a File Writer

I am attempting to write data to a file from a parameter that is stored within a SQL Server 2005 database. (The value of the entire file path can be retrieved by a query similar to "Select EDIOutputPath From SystemParms;.") I need to figure out how to first take the value returned by the query, which will be a string type, check to make sure that the directory listed exists. If the directory listed does not exist, I need to be able to create the directory. (For example, if the above query returns the output location "C:\test\EDI\", I need to be able to test if that location exists. If it exists then you move onto writing data to a file named abc.txt, for simplicity of testing. If the path does not exist, then the VB .NET 2010 code needs to create the directory before writing to the output file named "abc.txt") Any help that you would be able to provide with this task would be greatly appreciated. Also, how would I be able to test whether or not the location that is being written to is a "Shared" resource on a network where others are able to access the same folder via a server or a cluster of workstations that are on a network? (This would be done using VB .NET 2010 code.)