在Visual Basics中，我无法将输出显示在列表框中

Question

我试图编写Pythagorean三元组，但我不知道为什么添加到列表框不起作用。

Private Sub BtnCom_Click(sender As Object, e As EventArgs) Handles BtnCom.Click
    Dim A, B, C As Integer
    Dim num As Integer = 1
    Dim result As Integer
    C = hypotenuse(A, B)
    For A = 1 To 100
        For B = 1 To 100
            If (A ^ 2) + (B ^ 2) = (C ^ 2) And A < B Then
                num = num + 1
                result = num & "." & A & B & C & vbCr
                ListBox1.Items.Add(result)
            End If
        Next
    Next
End Sub

Function hypotenuse(A, B)
    Dim c2, c3 As Single
    c2 = (A ^ 2) + (B ^ 2)
    c3 = Math.Sqrt(c2)
    Return c3
End Function