Calculadora

Public Class Form1

    Dim op1 As Double
    Dim op2 As Double
    Dim operacion As String 'operacion solicitada
    Dim resultado As Double

    Private Sub btn1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn1.Click
        txtOperacion.Text += "1"
    End Sub

    Private Sub btn2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn2.Click
        txtOperacion.Text += "2"
    End Sub
    Private Sub btn3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn3.Click
        txtOperacion.Text += "3"
    End Sub

    Private Sub btn4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn4.Click
        txtOperacion.Text += "4"
    End Sub
    Private Sub btn5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn5.Click
        txtOperacion.Text += "5"
    End Sub

    Private Sub btn6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn6.Click
        txtOperacion.Text += "6"
    End Sub
    Private Sub btn7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn7.Click
        txtOperacion.Text += "7"
    End Sub

    Private Sub btn8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn8.Click
        txtOperacion.Text += "8"
    End Sub
    Private Sub btn9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn9.Click
        txtOperacion.Text += "9"
    End Sub

    Private Sub btn0_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn0.Click
        txtOperacion.Text += "0"
    End Sub

    Private Sub btnSumar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSumar.Click
        op1 = Convert.ToDouble(txtOperacion.Text)
        txtOperacion.Text = ""
        operacion = "+"
    End Sub

    Private Sub btnRestar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRestar.Click
        op1 = Convert.ToDouble(txtOperacion.Text)
        txtOperacion.Text = ""
        operacion = "-"
    End Sub

    Private Sub btnMultiplicar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnMultiplicar.Click
        op1 = Convert.ToDouble(txtOperacion.Text)
        txtOperacion.Text = ""
        operacion = "*"
    End Sub

    Private Sub btnDividir_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDividir.Click
        op1 = Convert.ToDouble(txtOperacion.Text)
        txtOperacion.Text = ""
        operacion = "/"
    End Sub

    Private Sub btnIgual_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnIgual.Click
        op2 = Convert.ToDouble(txtOperacion.Text)
        txtOperacion.Text = ""

        Select Case operacion
            Case "+"
                resultado = op1 + op2
            Case "-"
                resultado = op1 - op2
            Case "*"
                resultado = op1 * op2
            Case "/"
                resultado = op1 / op2
        End Select

        txtResultado.Text = resultado.ToString


    End Sub

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        txtOperacion.Text = ""
    End Sub
End Class