C# Winform 可空DateTimePicker V1.2

[csharp] 
using System; 
using System.Collections.Generic; 
using System.Text; 
using System.Windows.Forms; 
using System.ComponentModel; 
 
namespace WindowsFormsApplication1.Common 
{ 
    /// <summary> 
    /// 描述：可空值的DateTimePicker控件 v1.2 
    /// 作者：李偉波 
    /// 創建日期：2010-01-16 
    /// 修改日期：2012-07-17 修改賦值後不顯示時間的BUG、刪除時間後再打開面板未選擇時間也賦值的問題。 
    /// </summary> 
    public class DateTimePickerX : DateTimePicker 
    { 
        public DateTimePickerX() 
            : base() 
        { 
            SetNullText(); 
        } 
 
        /// <summary> 
        /// 值是否已改變 
        /// </summary> 
        private bool IsValueChanged = false; 
        /// <summary> 
        /// 原格式字符串 
        /// </summary> 
        private string _formatString = "yyyy年MM月dd日"; 
 
        /// <summary> 
        /// 原格式 
        /// </summary> 
        private DateTimePickerFormat _originalFormat = DateTimePickerFormat.Custom; 
 
        /// <summary> 
        /// 可空日期 
        /// </summary> 
        private DateTime? valueX = null; 
 
        /// <summary> 
        /// 日期(值改變前為null) 
        /// </summary> 
        [Browsable(true), Category("擴展屬性"), Description("可空日期(值改變前為null)")] 
        public DateTime? ValueX 
        { 
            get { return valueX; } 
            set 
            { 
                if (value == null) 
                { 
                    valueX = value; 
                    SetNullText(); 
                } 
                else 
                { 
                    this.CustomFormat = FormatString; 
                    this.Value = value.Value; 
                    valueX = value; 
                } 
            } 
        } 
        /// <summary> 
        /// 格式字符串 
        /// </summary> 
        [Browsable(true), Category("擴展屬性"), Description("格式字符串")] 
        public string FormatString 
        { 
            get { return _formatString; } 
            set { _formatString = value; } 
        } 
        /// <summary> 
        /// 設置格式 
        /// </summary> 
        [Browsable(true), Category("擴展屬性"), Description("設置格式")] 
        public DateTimePickerFormat OriginalFormat 
        { 
            get { return _originalFormat; } 
            set { _originalFormat = value; } 
        } 
        /// <summary> 
        /// 開始時間(該日期的00:00:00) 
        /// </summary> 
        [Browsable(true), Category("擴展屬性"), Description("開始時間(為當前選中日期的00:00:00)")] 
        public DateTime? BeginTime 
        { 
            get 
            { 
                if (ValueX.HasValue) 
                    return DateTime.Parse(ValueX.Value.ToString("yyyy-MM-dd 00:00:00")); 
                else 
                    return null; 
            } 
        } 
        /// <summary> 
        /// 結束時間(該日期的23:59:59) 
        /// </summary> 
        [Browsable(true), Category("擴展屬性"), Description("結束時間(為當前選中日期的23:59:59)")] 
        public DateTime? EndTime 
        { 
            get 
            { 
                if (ValueX.HasValue) 
                { 
                    return DateTime.Parse(ValueX.Value.ToString("yyyy-MM-dd 23:59:59")); 
                } 
                else 
                    return null; 
            } 
        } 
 
        /// <summary> 
        /// 設置空字符顯示 
        /// </summary> 
        private void SetNullText() 
        { 
            this.Format = System.Windows.Forms.DateTimePickerFormat.Custom; 
            this.CustomFormat = " "; 
        } 
 
        protected override void OnCloseUp(EventArgs eventargs) 
        { 
            if (IsValueChanged) 
            { 
                this.Format = _originalFormat; 
                this.CustomFormat = _formatString; 
                valueX = this.Value; 
                IsValueChanged = false; 
            } 
            base.OnCloseUp(eventargs); 
        } 
 
        protected override void OnValueChanged(EventArgs eventargs) 
        { 
            this.IsValueChanged = true; 
            base.OnValueChanged(eventargs); 
        } 
 
        protected override void OnKeyDown(KeyEventArgs e) 
        { 
            //刪除時間   www.2cto.com
            if (e.KeyCode == Keys.Back || e.KeyCode == Keys.Delete) 
            { 
                this.ValueX = null; 
                this.CustomFormat = " "; 
            } 
            base.OnKeyDown(e); 
        } 
 
    } 
} 
作者：ranbolwb