Function Return Statement Always Returns 0?

[IsaiahMatz]

Ok so here is my code(i apologize if some of the code wrapped around)

Public Class Form1
 
    Dim currentValue As String
    Dim dblCurrentValue As Double
    Dim newValue As Double
    Dim dblOldValue As Double
 
    Private Function GetBonus(ByRef dblOldValue) As Double
        Dim dblNewValue As Double
        dblNewValue = dblOldValue * 1.1
        Return dblNewValue
 
    End Function
 
    Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
        txtBox.Text = currentValue
        Double.TryParse(currentValue, dblCurrentValue)
 
        newValue = GetBonus(dblCurrentValue)
        txtBox.Text = newValue.ToString()
    End Sub
End Class

My question is, why is it that no matter what number i try to calculate, the end result is a zero? Im really new to this and im completely stumped. Thanks!

[Rabbit]

Please use code tags when posting code or formatted data.

Line 16 should be flipped. You are currently assigning a blank string to the textbox. If you try to parse that, a blank string will be parsed as 0.

[IsaiahMatz]

thank you so much! Sorry i didnt know their were code tags