我想把一个控件封装起来.DateTimePicker
因为他的value的类型为DateTime所以不可以为Null
但是数据库里有一些日期是为空的.如离职日期
现在我写了一个类继承至DateTimePicker
使用public object Value覆盖了基类的Value方法
这样它就可以为NULL了.
在使用时.我使用的是绑定
private MDateTimePicker dtpQuotationDate;
this.dtpQuotationDate.DataBindings.Add("Value", this.bindingSource1, "QuotationDate");
但是他一直只使用我这个类Value的Set方法,不使用我这个类的Value的Get方法,还是调动Base.Value.不知道为什么啊 ,请各位高手指点.谢谢!
using System;using System.Collections.Generic;using System.Text;using System.Windows.Forms;using System.ComponentModel;using System.Text.RegularExpressions;namespace WinUI
{ 
/**//// 
/// 用于处理DBNull问题的DateTimePicker
/// public class MDateTimePicker :DateTimePicker { private object dateValue; public new string Text { get { return this.dateValue.ToString(); } set { this.dateValue = value; } } public object Value { get { if (dateValue==null) { Format = DateTimePickerFormat.Custom; this.CustomFormat = " "; } else { this.Format = DateTimePickerFormat.Short; } return dateValue; } set { dateValue = value; base.Value = Convert.ToDateTime(value); } } protected override void OnTextChanged(EventArgs e) { //base.OnTextChanged(e); //if (Convert.ToDateTime(Value) == MaxDate) //{ // Format = DateTimePickerFormat.Custom; // CustomFormat = " "; //} //else //{ // Format = DateTimePickerFormat.Long; //} } protected override void OnClick(EventArgs e) { //base.OnClick(e); //onEdit(); } protected override void OnKeyDown(KeyEventArgs e) { base.OnKeyDown(e); if (e.KeyCode == Keys.Delete) { this.Value = null; } else { //onEdit(); } } private void onEdit() { Format = DateTimePickerFormat.Long; Value = DateTime.Now; } }
}