[مشروع] عمل آلة حاسبة بسيطة استعانة بـ Regex

كود :

Imports System.Text.RegularExpressions

Public Class Form1

    Dim res As String = String.Empty

    Private Sub b0_Click(sender As Object, e As EventArgs) Handles b0.Click, b1.Click, b2.Click, b3.Click, b4.Click, b5.Click, b6.Click, b7.Click, b8.Click, b9.Click

        If lblscreen.Text.Trim = "0" Then

            lblscreen.Text = sender.text

        Else

            lblscreen.Text &= sender.text

        End If

    End Sub

    Private Sub plus_Click(sender As Object, e As EventArgs) Handles plus.Click, minus.Click, mul.Click, div.Click

        If lblscreen.Text.IndexOf("+") > 0 Or lblscreen.Text.IndexOf("-") > 0 Or lblscreen.Text.IndexOf("*") > 0 Or lblscreen.Text.IndexOf("/") > 0 Then Exit Sub

        If lblscreen.Text.Trim = "0" Then

        Else

            lblscreen.Text &= sender.text

        End If

    End Sub

    Private Sub eq_Click(sender As Object, e As EventArgs) Handles eq.Click

        Dim str As String = "([0-9.]{1,})([/*\-+]{1,1})([0-9.]{1,})"

        Dim reg As New Regex(str)

        Dim ma As Match = reg.Match(lblscreen.Text.Trim)

        If ma.Success Then

            Select Case ma.Groups(2).Value

                Case "+"

                    res = ma.Groups(1).Value + Val(ma.Groups(3).Value)

                Case "-"

                    res = ma.Groups(1).Value - Val(ma.Groups(3).Value)

                Case "*"

                    res = ma.Groups(1).Value * Val(ma.Groups(3).Value)

                Case "/"

                    res = ma.Groups(1).Value / Val(ma.Groups(3).Value)

            End Select

            Dim the As String = " = " & res

            If lblscreen.Text.IndexOf(the) > 0 Then Exit Sub

            lblscreen.Text = ma.Groups(1).Value & " " & ma.Groups(2).Value & " " & ma.Groups(3).Value & " " & the

        End If

    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        lblscreen.Text = "0"

        res = String.Empty

    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub

    Private Function isfound() As Boolean

        If lblscreen.Text.Contains("/") Or

            lblscreen.Text.Contains("*") Or

            lblscreen.Text.Contains("-") Or

                lblscreen.Text.Contains("+") Then

            Return True

        Else

            Return False

        End If

    End Function

    Private Sub point_Click(sender As Object, e As EventArgs) Handles point.Click

        If lblscreen.Text.Trim = "0" Then

            Exit Sub

        Else

            Dim lapo As Integer = lblscreen.Text.LastIndexOf(".")

            If isfound() = False Then

                If lapo > 0 Then Exit Sub

            Else

                If lapo > 1 Then Exit Sub

            End If

            lblscreen.Text &= sender.text

        End If

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

        about.ShowDialog()

    End Sub

End Class