SoloCodigo

Imports vb = Microsoft.VisualBasic
Public Class Form1
    Public cad As String

    Private Sub btnconvertir_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnconvertir.Click
        Dim x, y As String
        Dim i, n, dec As Integer
        dec = 0
        x = vb.Trim(txtnum.Text)
        n = vb.Len(x)

        For i = 1 To n
            y = vb.Mid(x, i, 1)
            dec = dec + Val(y) * (2 ^ (n - i))

        Next
        txtresul.Text = dec
    End Sub

    Private Sub txtnum_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtnum.KeyPress
        Select Case e.KeyChar
            Case Chr(13) ' Enter
                btnconvertir.Focus()

            Case Chr(27) ' Escape
                End

            Case Chr(8) ' retroceso
            Case "0" ' el cero
            Case "1" ' el uno
            Case Else
                Beep()      ' Beep, prendé los parlantes
                e.Handled = True  'Impide el ingreso de caracteres ilegales
        End Select
    End Sub

    Private Sub txtnum_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtnum.TextChanged
        If txtnum.Text = "" Then
            btnconvertir.Enabled = False
        Else
            btnconvertir.Enabled = True
        End If
    End Sub

    Private Sub btnnuevo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnnuevo.Click
        txtnum.Text = ""
        txtresul.Text = ""
        txtnum.Focus()

    End Sub

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

    End Sub
End Class