[收藏]用C#写一个Web自定义控件

    技术2022-05-11  134

    这几天详细研究了一下msdn上Dino Esposito的分页控件</FONT>该控件是一个时间控件,通过下拉列表框选择时间的年、月、日、时、分、秒。初始化时要提供可选时间的 起始年份。 源代码如下: using System; using System.Web.UI; using System.Web.UI.WebControls; using System.ComponentModel; using System.ComponentModel.Design; namespace UserTime { /// <summary> /// 用户自定义时间控件,取到年、月、日、时、分、秒 /// </summary> [DefaultProperty("Text"), ToolboxData("<{0}:clsUserTime runat=server></{0}:clsUserTime>")] //INamingContainer为子控件提供了一个新的命名范围,保证子控件的ID唯一性 public class clsUserTime : System.Web.UI.WebControls.WebControl, INamingContainer { private System.Web.UI.WebControls.DropDownList ddlYear; private DropDownList ddlMonth; private DropDownList ddlDay; private DropDownList ddlHour; private DropDownList ddlMinite; private DropDownList ddlSecond; private static int beginYear = 0; //起始年号,这里必须使用static以防二次调用后变量被清零 private static bool IsInit = false; //是否已经初始化过,这里必须使用static以防二次调用后变量被清零 public int Year //取控件时间:年 { get { return ddlYear.SelectedIndex + beginYear; } } public int Month //取控件时间:月 { get { return ddlMonth.SelectedIndex + 1; } } public int Day //取控件时间:日 { get { return ddlDay.SelectedIndex + 1; } } public int Hour //取控件时间:时 { get { return ddlHour.SelectedIndex; } } public int Minite //取控件时间:分 { get { return ddlMinite.SelectedIndex; } } public int Second //取控件时间:秒 { get { return ddlSecond.SelectedIndex; } } //用起始年号初始化控件,如果已经初始化过控件,直接返回 public void InitControls(int startYear, int endYear) { if (IsInit) { return; } EnsureChildControls(); if (startYear > endYear) { int tmp = startYear; startYear = endYear; endYear = startYear; } beginYear = startYear; for (int i = startYear; i <= endYear; ++i) { ddlYear.Items.Add(i.ToString()); } for (int i = 1; i <=12; ++i) { ddlMonth.Items.Add(i.ToString()); } for (int i = 1; i <= 31; ++i) { ddlDay.Items.Add(i.ToString()); } for (int i = 0; i < 24; ++i) { ddlHour.Items.Add(i.ToString()); } for (int i = 0; i < 60; ++i) { ddlMinite.Items.Add(i.ToString()); ddlSecond.Items.Add(i.ToString()); } IsInit = true; } //重载Controls属性,取得ControlCollection对象,该对象表示UI层次结构中的服务器控件的子控件 public override ControlCollection Controls { get { //确定服务器是否包含子控件 EnsureChildControls(); return base.Controls; } } //动态创建子控件 protected override void CreateChildControls() { //创建年、月、日、时、分、秒下拉列表框 this.Controls.Clear(); ddlYear = new DropDownList(); ddlYear.ID = "ddlYear"; ddlYear.Width = 54; ddlMonth = new DropDownList(); ddlMonth.ID = "ddlMonth"; ddlMonth.Width = 40; ddlDay = new DropDownList(); ddlDay.ID = "ddlDay"; ddlDay.Width = 40; ddlHour = new DropDownList(); ddlHour.ID = "ddlHour"; ddlHour.Width = 40; ddlMinite = new DropDownList(); ddlMinite.ID = "ddlMinite"; ddlMinite.Width = 40; ddlSecond = new DropDownList(); ddlSecond.ID = "ddlSecond"; ddlSecond.Width = 40; this.Controls.Add(ddlYear); this.Controls.Add(ddlMonth); this.Controls.Add(ddlDay); this.Controls.Add(ddlHour); this.Controls.Add(ddlMinite); this.Controls.Add(ddlSecond); base.CreateChildControls (); } /// <summary> /// 将此控件呈现给指定的输出参数。 /// </summary> /// <param name="output"> 要写出到的 HTML 编写器 </param> protected override void Render(HtmlTextWriter output) { //将要呈现的HTML属性添加到指定的System.Web.HtmlTextWriter中 AddAttributesToRender(output); output.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Cellpadding, "0", false); //制定一个表,把子控件排在一行上 output.RenderBeginTag(HtmlTextWriterTag.Table); //表 output.RenderBeginTag(HtmlTextWriterTag.Tr); //行 //年下拉列表框 output.RenderBeginTag(HtmlTextWriterTag.Td); //列 ddlYear.RenderControl(output); output.RenderEndTag(); output.RenderBeginTag(HtmlTextWriterTag.Td); output.Write("年"); output.RenderEndTag(); //月下拉列表框 output.RenderBeginTag(HtmlTextWriterTag.Td); ddlMonth.RenderControl(output); output.RenderEndTag(); output.RenderBeginTag(HtmlTextWriterTag.Td); output.Write("月"); output.RenderEndTag(); //日下拉列表框 output.RenderBeginTag(HtmlTextWriterTag.Td); ddlDay.RenderControl(output); output.RenderEndTag(); output.RenderBeginTag(HtmlTextWriterTag.Td); output.Write("日"); output.RenderEndTag(); //时下拉列表框 output.RenderBeginTag(HtmlTextWriterTag.Td); ddlHour.RenderControl(output); output.RenderEndTag(); output.RenderBeginTag(HtmlTextWriterTag.Td); output.Write("时"); output.RenderEndTag(); //分下拉列表框 output.RenderBeginTag(HtmlTextWriterTag.Td); ddlMinite.RenderControl(output); output.RenderEndTag(); output.RenderBeginTag(HtmlTextWriterTag.Td); output.Write("分"); output.RenderEndTag(); //秒下拉列表框 output.RenderBeginTag(HtmlTextWriterTag.Td); ddlSecond.RenderControl(output); output.RenderEndTag(); output.RenderBeginTag(HtmlTextWriterTag.Td); output.Write("秒"); output.RenderEndTag(); output.RenderEndTag(); output.RenderEndTag(); } public DateTime GetTime() //取得选定的时间 { DateTime time = new DateTime(this.Year, this.Month, this.Day, this.Hour, this.Minite, this.Second, 0); return time; } //清除控件里所有下拉列表框的值 public void ClearControls() { ddlYear.Items.Clear(); ddlMonth.Items.Clear(); ddlDay.Items.Clear(); ddlHour.Items.Clear(); ddlMinite.Items.Clear(); ddlSecond.Items.Clear(); IsInit = false; } //撤消对所有下拉列表框的选项 public void ClearSelection() { ddlYear.ClearSelection(); ddlMonth.ClearSelection(); ddlDay.ClearSelection(); ddlHour.ClearSelection(); ddlMinite.ClearSelection(); ddlSecond.ClearSelection(); } } }

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