Calculater

السلام عليكم

بداية قمت بتعريف عملية الجمع ولكن المشكلة في الناتح لا يعرض على الـ txtDisplay بعد ان اضغط على الـ =

Partial Class _Default
    Inherits System.Web.UI.Page
    Dim pm, num1, num2, sum As Double       'Variable
    Dim plu, min, multiplay, dec As Integer 'Operation

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        txtDisplay.Text = ("")
        dec = 0
    End Sub

    Protected Sub Button9_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button9.Click
        txtDisplay.Text = txtDisplay.Text & Button9.Text

    End Sub

    Protected Sub Button10_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button10.Click
        txtDisplay.Text = txtDisplay.Text & Button10.Text
    End Sub

    Protected Sub Button11_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button11.Click
        txtDisplay.Text = txtDisplay.Text & Button11.Text
    End Sub

    Protected Sub Button13_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button13.Click
        txtDisplay.Text = txtDisplay.Text & Button13.Text
    End Sub

    Protected Sub Button14_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button14.Click
        txtDisplay.Text = txtDisplay.Text & Button14.Text
    End Sub

    Protected Sub Button15_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button15.Click
        txtDisplay.Text = txtDisplay.Text & Button15.Text
    End Sub

    Protected Sub Button17_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button17.Click
        txtDisplay.Text = txtDisplay.Text & Button17.Text
    End Sub

    Protected Sub Button18_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button18.Click
        txtDisplay.Text = txtDisplay.Text & Button18.Text
    End Sub

    Protected Sub Button19_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button19.Click
        txtDisplay.Text = txtDisplay.Text & Button19.Text
    End Sub

    Protected Sub Button21_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button21.Click
        txtDisplay.Text = txtDisplay.Text & Button21.Text
    End Sub

    Protected Sub Button16_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button16.Click
        num1 = (Convert.ToDouble(txtDisplay.Text))
        num2 = (Convert.ToDouble(txtDisplay.Text))
        txtDisplay.Text = ("")
        plu = 1
        dec = 0
    End Sub

    Protected Sub Button24_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button24.Click
        If (plu > 0) Then   (هذا كود الـ = button)
            sum = num1 + num2
            txtDisplay.Text = sum.ToString()
            num1 = 0.0
            num2 = 0.0
            plu = 0
        End If


    End Sub
End Class