[مشروع] آلة حاسبة عن طريقة مناداة الدالة من ملف dll

كود :

Public Class myfunc

    Public Function retv(ByVal v1 As Double, ByVal v2 As Double, ByVal o As String)

        Dim res As Double

        Select Case o

            Case "/"

                res = v1 / v2

            Case "*"

                res = v1 * v2

            Case "-"

                res = v1 - v2

            Case "+"

                res = v1 + v2

        End Select

        Return res

    End Function

End Class

كود :

Imports Mydll

Public Class Form1

    Dim i1, i2 As String

    Dim o As String = ""

    Dim v As New myfunc

    Private Function isfound() As Boolean

        If o = "" Then

            Return False

        Else

            Return True

        End If

    End Function

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

        Dim ne As String = " = "

        If t1.Text.IndexOf(ne) > 0 Then Exit Sub

        t1.Text = i1 & " " & i2 & " " & ne & v.retv(i1, i2, o)

    End Sub

    Private Sub btn0_Click(sender As Object, e As EventArgs) Handles btn0.Click, btn1.Click, btn2.Click, btn3.Click, btn4.Click, btn5.Click, btn6.Click, btn7.Click, btn8.Click, btn9.Click

        If o = "" Then

            i1 &= sender.text

            t1.Text &= sender.text

        Else

            i2 &= sender.text

            t1.Text &= sender.text

        End If

    End Sub

    Private Sub Button11_Click(sender As Object, e As EventArgs) Handles btndiv.Click, btnmul.Click, btnmin.Click, btnplus.Click

        o = sender.text

        t1.Text &= sender.text

    End Sub

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

        o = ""

        i1 = ""

        i2 = ""

        t1.Clear()

    End Sub

    Private Sub poin_Click(sender As Object, e As EventArgs) Handles poin.Click

        If isfound() = False Then

            i1 &= "."

        Else

            i2 &= "."

        End If

        t1.Text &= "."

    End Sub

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

    End Sub

End Class