可用来显示空值的时间选择控件2

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;

namespace XPangLib
{
///

/// DateInput 的摘要说明。
///

public class DateInput : System.Windows.Forms.UserControl
{
#region 成员控件

private System.Windows.Forms.MonthCalendar Calendar ;
private System.Windows.Forms.Form frmCalendar ;
private System.Windows.Forms.Panel panel3;
private System.Windows.Forms.Button btnMain;
private System.Windows.Forms.VScrollBar UpDown;
private System.Windows.Forms.Panel panel1;
private System.Windows.Forms.Panel panel2;
private System.Windows.Forms.Label lbSep3;
private System.Windows.Forms.TextBox tbDay;
private System.Windows.Forms.Label lbSep2;
private System.Windows.Forms.TextBox tbMonth;
private System.Windows.Forms.Label lbSep1;
private System.Windows.Forms.TextBox tbYear;
private System.Windows.Forms.Label label2;
private System.Windows.Forms.Label lbSpace;
#endregion

///

/// 必需的设计器变量。
///

private System.ComponentModel.Container components = null;

private ContextMenu mnu = new ContextMenu() ;