VB.NET；输出有时不会出现在 richtextbox

Question

这是我的代码：

Public Class Form1
    Dim A, B, Tambah, Kurang, Kali, Bagi, Hasil, HasilUji, x, y As Double

    Private Sub Variabel()
        A = tbAngka1.Text : B = tbAngka2.Text
    End Sub

    Private Sub Kalkulasi()
        'Perhitungan Sederhana
        Tambah = A + B : Kurang = A - B : Kali = A * B : Bagi = A / B
    End Sub

    Private Sub btnUji_Click(sender As Object, e As EventArgs) Handles btnUji.Click
        rcHasil.Clear()

        Variabel()
        Kalkulasi()

'THE PROBLEM START HERE (WHILE)
'PLEASE HELP ME
'THIS SPAGGETTI CODE RUINING MY DAY :)

        'While
        'Segitiga
        If rbWhile.Checked Then
            Do While x <= Hasil '--> x = 1 : Hasil = 5
                y = 1
                Do While y <= x
                    rcHasil.Text += y.ToString
                    y += 1
                Loop
                rcHasil.Text += vbCrLf '--> vbCrLf : Utk ubah tampilan output Vertikal ke Horizontal
                x += 1
            Loop

            'Segitiga Terbalik
        ElseIf rbWhileTerbalik.Checked Then
            Do While x <= Hasil
                y = 1
                Do While y <= Hasil - x
                    rcHasil.Text += y.ToString
                    y += 1
                Loop
                rcHasil.Text += vbCrLf
                x += 1
            Loop

            'Play Button
        ElseIf rbWhilePlayButton.Checked Then
            Do While x <= Hasil
                y = 1
                Do While y <= x
                    rcHasil.Text += y.ToString
                    y += 1
                Loop
                rcHasil.Text += vbCrLf
                x += 1
            Loop

            Do While x >= 1
                y = 1
                Do While y < x - 1
                    rcHasil.Text += y.ToString
                    y += 1
                Loop
                rcHasil.Text += vbCrLf
                x -= 1
            Loop
        End If
    End Sub
End Class

While的输出有时不出现

需要帮助修复我的意大利面条代码:)