创建ASP.NET WEB自定义控件——例程2

创建ASP.NET WEB自定义控件——例程2(标准化越来越近了):namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

作者：大毛

本文通过一段完整的代码向读者介绍复合自定义控件的制作，包括：自定义属性、事件处理、控件间数据传递等方面的技术。

作者在http://damao.0538.org有一些控件和代码，并在更新中，有兴趣的读者可以去下载。

以下是一个登陆框的代码，包括：用户名输入TextBox、密码输入TextBox、提交Button、重置Button以及承载以上四项的Panel。控件类名为LoginCtrl。

（例程使用C#）

using System;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.ComponentModel;

using System.Drawing;

namespace TestLib

{

     [DefaultProperty("BackColor"),

         ToolboxData("<{0}:LoginCtrl runat=server></{0}:LoginCtrl>")]

     public class LoginCtrl : System.Web.UI.WebControls.WebControl

     {

         private Color _fontColor = Color.Black;//声明字体颜色变量

         private Color _backColor = Color.White;//声明控件背景变量

首先声明要在复合控件中使用的子控件。

         private Label lblUserName = new Label();//显示“用户名”的Label控件

         private Label lblPassWord = new Label();//显示“密码”的Label控件

         private TextBox txtUserName = new TextBox();//用户名输入的TextBox控件

         private TextBox txtPassWord = new TextBox();//密码输入的TextBox控件

         private Button submitButton = new Button();//提交Button控件

         private Button clearButton = new Button();//重置Button控件

         private System.Web.UI.WebControls.Panel pnlFrame = new System.Web.UI.WebControls.Panel();//承载其它控件的容器Panel控件

当然要在符合控件中使用的事件一定要声明的，它们会出现在属性框的事件栏里。

         public event EventHandler SubmitOnClick;//声明自定义控件LoginCtrl的提交事件

         public event EventHandler ClearOnClick;//声明自定义控件LoginCtrl的重置事件

         public LoginCtrl()

         {

刚刚声明的子控件和事件要在这里进行初始化处理。

//初始化控件的属性

              this.lblUserName.Text = "用户名:";

              this.lblPassWord.Text = "密  码:";

              this.txtPassWord.TextMode = System.Web.UI.WebControls.TextBoxMode.Password;

              this.pnlFrame.Width = 240;

              this.pnlFrame.Height = 120;

              this.pnlFrame.BackColor = Color.Empty;

//添加提交按钮点击事件

              submitButton.Text = "确定";

              submitButton.Click += new EventHandler(this.SubmitBtn_Click);

//添加重置按钮点击事件

              clearButton.Text = "重置";

              clearButton.Click += new EventHandler(this.ClearBtn_Click);

//将声明的各子控件添加到LoginCtrl中

              this.Controls.Add(this.submitButton);

              this.Controls.Add(this.clearButton);

              this.Controls.Add(this.txtUserName);

              this.Controls.Add(this.txtPassWord);

              this.Controls.Add(this.lblUserName);

              this.Controls.Add(this.lblPassWord);

              this.Controls.Add(this.pnlFrame);

         }

根据自己的需要添加或重载符合控件的公共属性

//字体颜色属性

         [Bindable(false),

              Category("Appearance"),

              DefaultValue("")]

         public override Color ForeColor

         {

              get

              {

                   return this._fontColor;

              }

              set

              {

                   this._fontColor = value;

              }

         }

//控件背景属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public override Color BackColor

         {

              get

              {

                   return this._backColor;

              }

              set

              {

                   this._backColor = value;

              }

         }

//用户名属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public string UserName

         {

              get

              {

                   return this.txtUserName.Text;

              }

              set

              {

                   this.txtUserName.Text = value;

              }

         }

//密码属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue(""), Browsable(false)]

         public string PassWord

         {

              get

              {

                   return this.txtPassWord.Text;

              }

              set

              {

                   this.txtPassWord.Text = value;

              }

         }

//控件宽度属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public override Unit Width

         {

              get

              {

                   return this.pnlFrame.Width;

              }

              set

              {

                   this.pnlFrame.Width = value;

              }

         }

//控件高度属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public override Unit Height

         {

              get

              {

                   return this.pnlFrame.Height;

              }

              set

              {

                   this.pnlFrame.Height = value;

              }

         }

//控件边框颜色属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public override Color BorderColor

         {

              get

              {

                   return this.pnlFrame.BorderColor;

              }

              set

              {

                   this.pnlFrame.BorderColor = value;

              }

         }

//控件边框样式属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public override BorderStyle BorderStyle

         {

              get

              {

                   return this.pnlFrame.BorderStyle;

              }

              set

              {

                   this.pnlFrame.BorderStyle = value;

              }

         }

//控件边框宽度属性

         [Bindable(false),

         Category("Appearance"),

         DefaultValue("")]

         public override Unit BorderWidth

         {

              get

              {

                   return this.pnlFrame.BorderWidth;

              }

              set

              {

                   this.pnlFrame.BorderWidth = value;

              }

         }

下面要把控件输出出去，展示在页面上。

         /// <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)

         {

              this.pnlFrame.RenderBeginTag(output);//输出Panel控件

     //在Panel中绘制表格

              output.AddAttribute(HtmlTextWriterAttribute.Border,"0");

              output.AddAttribute(HtmlTextWriterAttribute.Cellpadding,"0");

              output.AddAttribute(HtmlTextWriterAttribute.Cellspacing,"0");

              output.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Width,"100%");

              output.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Height,"100%");

              output.AddAttribute(HtmlTextWriterAttribute.Bgcolor,this._backColor.Name);

              output.RenderBeginTag(HtmlTextWriterTag.Table);

              output.RenderBeginTag(HtmlTextWriterTag.Tr);

              output.RenderBeginTag(HtmlTextWriterTag.Td);

              //在表格中添加Label控件

              this.lblUserName.ForeColor = this._fontColor;

              this.lblUserName.RenderControl(output);

              output.RenderEndTag();

              output.RenderBeginTag(HtmlTextWriterTag.Td);

              //在表格中添加TextBox控件

              this.txtUserName.RenderControl(output);

              output.RenderEndTag();

              output.RenderEndTag();

              output.RenderBeginTag(HtmlTextWriterTag.Tr);

              output.RenderBeginTag(HtmlTextWriterTag.Td);

              //在表格中添加Label控件

              this.lblPassWord.ForeColor = this._fontColor;

              this.lblPassWord.RenderControl(output);

              output.RenderEndTag();

              output.RenderBeginTag(HtmlTextWriterTag.Td);

//在表格中添加TextBox控件

              this.txtPassWord.RenderControl(output);

              output.RenderEndTag();

              output.RenderEndTag();

              output.RenderBeginTag(HtmlTextWriterTag.Tr);

              output.AddAttribute(HtmlTextWriterAttribute.Align,"right");

              output.RenderBeginTag(HtmlTextWriterTag.Td);

              //在表格中添加Button控件

              this.submitButton.RenderControl(output);

              output.RenderEndTag();

              output.AddAttribute(HtmlTextWriterAttribute.Align,"center");

              output.RenderBeginTag(HtmlTextWriterTag.Td);

              //在表格中添加Button控件

              this.clearButton.RenderControl(output);

              output.RenderEndTag();

              output.RenderEndTag();

              output.RenderEndTag();

              this.pnlFrame.RenderEndTag(output);

         }

当按钮点击时怎么做呢？这是个事件冒泡。

         //处理提交按钮点击事件

         private void SubmitBtn_Click(object sender, EventArgs e)

         {

              EventArgs e1 = new EventArgs();

              if(this.SubmitOnClick!=null)

                   this.SubmitOnClick(this.submitButton,e1);

         }

         //处理重置按钮点击事件

         private void ClearBtn_Click(object sender, EventArgs e)

         {

              this.txtPassWord.Text = "";

              this.txtUserName.Text = "";

              EventArgs e1 = new EventArgs();

              if(this.ClearOnClick!=null)

                   this.ClearOnClick(this.clearButton,e1);

         }

     }

}

编译一下，OK！

这个控件没有什么实际的使用价值，本文制作这个例子是为了向读者展示复合控件的制作方法，也很简单，是吧？