用C#写一个Web自定义控件

王朝c#·作者佚名 2006-01-09

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原来写的用户控件，但是维护太麻烦，后来就写了一个自定义控件，比较好维护，使用也方便多了。

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();