Conditional Linq value and a beautiful solution

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Having little to no experience with Linq this one was rather tough. .  I googled Conditional Data Entity but found nothing as slick as this solution a friend sent me.

 So the problem was this ... I had some textboxes, date fields etc for report filters but the textbox was OPTIONAL.  I wanted to manage the condition in the query.  

 So here is what we came up with:
var dbRecords = (from c in context.myTable

where (string.IsNullOrEmpty(bnum) || string.Compare(c.BNumber, bnum, true) == 0)
 && (c.DateRan >= startdate && c.DateRan <= enddate)

 And the way this works  - if bnum has a value then we will select where c.BNumber = bnum otherwise we don't use it in the where statement at all.  Really made life easy!

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