title: linq query dynamically add where condition?
body: <p>I want to filter records dynamically on user choice. The user may choose to show the debit amount greater than credit or credit amount greater than debit. Accordingly I want to put a condition similar to either <code>totDebit&gt;totCredit or</code>TotCredit>totDebit`</p>
  
  <pre><code>Dim query = _
          From product In Bills.AsEnumerable() _
          Group product By accode = product.Field(Of String)("ACCODE"), _
          BILLNO = product.Field(Of String)("BILLNO") Into g = Group _
          Let totDebit = g.Sum(Function(proudct) proudct.Field(Of Decimal)("DEBIT")) _
          Let totCredit = g.Sum(Function(proudct) proudct.Field(Of Decimal)("CREDIT")) _
          Select New With _
           { _
              .ACCODE = accode, _
              .billno = BILLNO, _
              .TOTALDEBIT = totDebit, _
              .TOTALCREDIT = totCredit, _
              .BALNACE = totDebit - totCredit _
            }
  </code></pre>
  
  <p>How can this be done?</p>