RETO 4 – Operación Aritmética

Public Class Form1

    Private Sub txtb_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtb.TextChanged

        If txta.Text <> "" And txtb.Text <> "" Then

            btncalcular.Enabled = True

        Else

            btncalcular.Enabled = False

        End If

    End Sub

    Private Sub txta_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txta.TextChanged

        If txta.Text <> "" And txtb.Text <> "" Then

            btncalcular.Enabled = True

        Else

            btncalcular.Enabled = False

        End If

    End Sub

    Private Sub btncalcular_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btncalcular.Click

        Dim m, d, s, r As Double

        s = Val(txta.Text) + Val(txtb.Text)

        r = Val(txta.Text) - Val(txtb.Text)

        m = Val(txta.Text) * Val(txtb.Text)

        d = Val(txta.Text) / Val(txtb.Text)

        lstresultado.Items.Clear()

        If chkloperacion.GetItemCheckState(0) = CheckState.Checked Then

            lstresultado.Items.Add(Val(txta.Text) & " + " & Val(txtb.Text) & "  = " & s)

        End If

        If chkloperacion.GetItemCheckState(1) = CheckState.Checked Then

            lstresultado.Items.Add(Val(txta.Text) & " - " & Val(txtb.Text) & "   = " & r)

        End If

        If chkloperacion.GetItemCheckState(2) = CheckState.Checked Then

            lstresultado.Items.Add(Val(txta.Text) & " * " & Val(txtb.Text) & "   = " & m)

        End If

        If chkloperacion.GetItemCheckState(3) = CheckState.Checked Then

            lstresultado.Items.Add(Val(txta.Text) & " / " & Val(txtb.Text) & "   = " & d)

        End If

    End Sub

    Private Sub btnsalir_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnsalir.Click

        Dim salida As Integer = MsgBox("desea salir de verdad?", MsgBoxStyle.YesNo + 32, "Mensaje")

        If salida = 6 Then

            End

        End If

    End Sub

    Private Sub txta_Validating(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txta.Validating

        If Not IsNumeric(txta.Text) Then

            Me.epcod.SetError(Me.txta, "Error ingrese dato tipo Numerico")

            Me.txta.Focus()

        Else

            Me.epcod.SetError(Me.txta, "")

        End If

    End Sub

    Private Sub txtb_Validating(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtb.Validating

        If Not IsNumeric(txtb.Text) Then

            Me.epcod.SetError(Me.txtb, "Error ingrese dato tipo Numerico")

            Me.txtb.Focus()

        Else

            Me.epcod.SetError(Me.txtb, "")

        End If

    End Sub

End Class