.NET自定义控件开发1

1.了解控件之间的继承关系

  首先先看看System.Web.UI命名空间

(1)Control 类，所有的控件都共享的一个类，你需要去看下其里面受保护的几个方法和属性，虽然一下看不完，以后会发现常常用到这些方法

大家可以在MSDN看一下其派生类

(2)HtmlTextWriter 类

不得不了解的一个类，主要工作就是我们写的标记字符和文本输出

 

示例一

首先先创建一个类库，命名OurControl

using System;
using System.Web.UI;

/// <summary>
/// OurControl的摘要说明
/// </summary>
public class OurControl: Control
{
    protected override void Render(HtmlTextWriter writer)
    {
        writer.Write("<table style='width:287px;height:124px;border-width:0;'>");
        writer.Write("<tr>");
        writer.Write("<td><strong>Payment Method</strong></td>");
        writer.Write("<td>");
        writer.Write("<select name='PaymentMethod' id='PaymentMethod' style='width:100%;'>");
        writer.Write("<option value='0'>Visa</option>");
        writer.Write("<option value='1'>MasterCard</option>");
        writer.Write("</select>");
        writer.Write("</td>");
        writer.Write("</tr>");
        writer.Write("<tr>");
        writer.Write("<td><strong>Credit Card No.</strong></td>");
        writer.Write("<td><input name='CreditCardNo' id='CreditCardNo' type='text' /></td>");
        writer.Write("</tr>");
        writer.Write("<tr>");
        writer.Write("<td><strong>Cardholder's Name</strong></td>");
        writer.Write("<td><input name='CardholderName' id='CardholderName' type='text' /></td>");
        writer.Write("</tr>");
        writer.Write("<tr>");
        writer.Write("<td><strong>Expiration Date</strong></td>");
        writer.Write("<td>");
        writer.Write("<select name='Month' id='Month'>");
        for (int day = 1; day < 13; day++)
        {
            if (day < 10)
                writer.Write("<option value='" + day.ToString() + "'>" + "0" + day.ToString() + "</option>");
            else
                writer.Write("<option value='" + day.ToString() + "'>" + day.ToString() + "</option>");
        }
        writer.Write("</select>");
        writer.Write("&nbsp");
        writer.Write("<select name='Year' id='Year'>");
        for (int year = 2005; year < 2015; year++)
        {
            writer.Write("<option value='" + year.ToString() + "'>" + year.ToString() + "</option>");
        }
        writer.Write("</select>");
        writer.Write("</td>");
        writer.Write("</tr>");
        writer.Write("<tr>");
        writer.Write("<td align='center' colspan='2'>");
        writer.Write("<input type='submit' value='Submit' />");
        writer.Write("</td>");
        writer.Write("</tr>");
        writer.Write("</table>");

        base.Render(writer);
    }
}

使用控件

(1).需要先注册一下

<%@ Register Assembly="ClassLibrary1" Namespace="ClassLibrary1" TagPrefix="cc1" %>

(2) 然后就使用标签输出效果

<cc1:OurControl runat="server" ID="ccf" >

</cc1:OurControl>