Help with calculations on button click

Not really sure what my problem is but here we go.
Ive created a simple windows form in visual studio to calculate an NPS (Net Promoter Score) average. Everything is finally working with one exception. When I click my calculate button only half of the calculations are done, I have to click it once more to get the code to finish. Im new to vb but it seems to me like the problem is the code is getting ahead of itself and since the end formula needs the results from several of my labels it cant finish. Im sure its a simple fix but I cant quit get it. Any assistance would be much appreciated.

Code:

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Private Sub butCalculate_Click(sender As Object, e As EventArgs) Handles butCalculate.Click
        Dim detracter As Double
        Dim neutral As Double
        Dim promoter As Double
        Dim total As Double
        Dim TOTAL1 As Double

        detracter = Double.Parse(lblD.Text)
        neutral = Double.Parse(lblN.Text)
        promoter = Double.Parse(lblP.Text)

        lblD.Text = Val(lblD.Text) + txtDetractor.Text
         
        lblN.Text = Val(lblN.Text) + txtNeutrals.Text

        lblP.Text = Val(lblP.Text) + txtPromoters.Text

            TOTAL1 = (promoter - detracter) / (promoter + neutral + detracter)
            lblTotal.Text = TOTAL1.ToString("P")
            lblTotal.Visible = True
            lblTotal.Left = (Me.ClientSize.Width / 2) - (lblTotal.Width / 2)

            txtDetractor.Text = "0"
            txtNeutrals.Text = "0"
        txtPromoters.Text = "0"

        total = detracter + neutral + promoter
        lblT.Text = total.ToString()

    End Sub

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Code does not ever get ahead of itself, it executes line by line top to bottom unless you code it to skip or loop lines along the way which here you have not.

Lines like this are a concern

Code:

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lblD.Text = Val(lblD.Text) + txtDetractor.Text

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I'm not sure there if you are trying to add those values or combine them. I assume that you are trying to add but one you are converting to a number and the other is a string so at best it is poor practice.
You should use numeric variables for math and strings for strings also should use & to put strings together.

That said it would seem that maybe your problem is the order of your code. You assign a value to 3 vars from your labels you then change those label values but those new values are not used in your calculation because they happen after you set your vars.

If you are getting the values you expect the first time when you click the button again then that indicates to me that you meant to add the adjusted values.


In other words it looks like these three lines

Code:

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detracter = Double.Parse(lblD.Text)
neutral = Double.Parse(lblN.Text)
promoter = Double.Parse(lblP.Text)

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Need to be moved down to a point after the next three lines.

So the code is not getting ahead of itself, it is just not coded correctly