InputBox en C#

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Windows.Forms;
namespace ProyectoABC //aqui va el nombre del proyecto
{
public static class Inputbox
{
static Form f;
static Label l;
static TextBox t;
static Button b1;
static Button b2;
static string Valor;

public static string Show(string title, string prompt, FormStartPosition posicion)
{
f = new Form();
f.Text = title;
f.ShowIcon = false;
f.Icon = null;
f.KeyPreview = true;
f.ShowInTaskbar = false;
f.MaximizeBox = false;
f.MinimizeBox = false;
f.Width = 200;
f.FormBorderStyle = FormBorderStyle.FixedDialog;
f.Height = 120;
f.StartPosition = posicion;
f.KeyPress += new KeyPressEventHandler(f_KeyPress);

l = new Label();
l.AutoSize = true;
l.Text = prompt;


t = new TextBox();
t.Width = 182;
t.Top = 40;

b1 = new Button();
b1.Text = "Aceptar";
b1.Click += new EventHandler(b1_Click);


b2 = new Button();
b2.Text = "Cancelar";
b2.Click += new EventHandler(b2_Click);

f.Controls.Add(l);
f.Controls.Add(t);
f.Controls.Add(b1);
f.Controls.Add(b2);

l.Top = 10;
t.Left = 5;
t.Top = 30;

b1.Left = 5;
b1.Top = 60;

b2.Left = 112;
b2.Top = 60;

f.ShowDialog();
return (Valor);
}

static void f_KeyPress(object sender, KeyPressEventArgs e)
{
switch (Convert.ToChar(e.KeyChar))
{

case ('\r'):
Acepta();
break; ;
case (''):
Cancela();
break; ;
}
}
static void b2_Click(object sender, EventArgs e)
{
Cancela();
}
static void b1_Click(object sender, EventArgs e)
{
Acepta();
}
private static string Val
{
get { return (Valor); }
set { Valor = value; }
}
private static void Acepta()
{
Val = t.Text;
f.Dispose();
}
private static void Cancela()
{
Val = null;
f.Dispose();
}
}
}