TryParse method is reading negative value and turning it to a positive 0 in VB.Net code

Question

I created this code in order to get the total sum of these values.

  Dim budget As Double
  If gv_DO_Tasks.Rows.Count() = 0 Then
        lblTotalTaskTotalBudget.Text = ""
        Return
    End If
    For Each i As GridViewRow In gv_DO_Tasks.Rows
        Dim amount As String = Replace(i.Cells(6).Text, "$", " ")
        Dim value As Double
        If Double.TryParse(amount, value) = True Then               
            budget = budget + value
        End If
        
    Next 

The issue is that I have a negative value as one of the amounts and when I try to do the TryParse method to convert the amount which is a string to a double, the value becomes 0 as a positive integer instead of the previous value which is ($26,652.25) or -$26,652.25 That messes up the total which is supposed to be less. The total sum is showing $989,992.74 but it should be $963,340.49.

Is there anything I have to add to the code or change?

Please help, thank you.

Answer 1

I suspect replacing the dollar sign with a space is leaving you with something like this:

- 26,642.25

Notice the space between the negative sign and the value. If you replace the dollar sign with an empty string instead, I'd bet the code will work:

Dim amount As String = Replace(i.Cells(6).Text, "$", "")

I might also be tempted to write a utility/library method like this:

<Extension()> 
Public Shared Iterator Function WhereDoubleParses(Of T)(items As IEnumerable(Of T), selector As Func(Of T, Double)) As IEnumerable(Of Double)
    For Each item As T in items
         Dim result As Double
         If (Double.TryParse(selector(item), result) Then
              Yield result
         End If
    Next
End Function

Which I would then use to reduce the original For loop down to this:

budget = gv_DO_Tasks.Rows.
     WhereDoubleParses(Function(i) i.Cells(6).Text.Replace("$", "")).
     Sum()