服务端控件开发包含处理机制—— 子控件中调用住空间委托的事件实例

最新推荐文章于 2025-11-04 16:42:09 发布

转载最新推荐文章于 2025-11-04 16:42:09 发布 · 515 阅读

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#textbox #object #button #string #class #null

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本文介绍了一个自定义ASP.NET服务器控件——搜索控件的实现细节。该控件包括一个按钮和一个文本框，通过按钮点击触发搜索事件并传递文本框中的值。文章详细展示了控件的创建过程及如何响应事件。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace ServerControl
{
    [DefaultProperty("Text")]
    [ToolboxData("<{0}:SearchControl runat=server></{0}:SearchControl>")]
    public class SearchControl : CompositeControl
    {
        private Button btnSearch;
        private TextBox tbSearchText;

        [Category("搜索")]
        [DefaultValue("")]
        [Description("获取文本的值")]
        public string Text
        {
            get
            {
                this.EnsureChildControls();
                return tbSearchText.Text;
            }
        }

        private static readonly object ButtonSearchClickObject = new object();

        public event SearchEventHandler ButtonSearchClick
        {
            add
            {
                base.Events.AddHandler(ButtonSearchClickObject, value);
            }
            remove
            {
                base.Events.RemoveHandler(ButtonSearchClickObject, value);
            }
        }

        protected override void CreateChildControls()
        {
            //base.CreateChildControls();
            this.Controls.Clear();
            btnSearch = new Button();
            btnSearch.ID = "btn";
            btnSearch.Text = "搜索";
            btnSearch.Click += new EventHandler(btnSearch_Click);

            tbSearchText = new TextBox();
            tbSearchText.ID = "tb";
            this.Controls.Add(btnSearch);
            this.Controls.Add(tbSearchText);
        }

        protected virtual void OnButtonSearchClick(SearchEventArgs e)
        { 
            SearchEventHandler ButtonSearchClickHandler=(SearchEventHandler)base.Events[ButtonSearchClickObject];
            if (ButtonSearchClickHandler != null)
            {
                ButtonSearchClickHandler(this, e);
            }
        }

        void btnSearch_Click(object sender, EventArgs e)
        {
            //throw new NotImplementedException();
            SearchEventArgs args = new SearchEventArgs();
            args.SearchValue = this.Text;
            OnButtonSearchClick(args);
        }

        protected override void Render(HtmlTextWriter writer)
        {
            writer.AddAttribute(HtmlTextWriterAttribute.Border, "0px");
            writer.AddAttribute(HtmlTextWriterAttribute.Cellpadding, "0px");
            writer.AddAttribute(HtmlTextWriterAttribute.Cellspacing, "0px");
            writer.RenderBeginTag(HtmlTextWriterTag.Table);
            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            tbSearchText.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            btnSearch.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();
            writer.RenderEndTag();
        }

        public delegate void SearchEventHandler(object sender, SearchEventArgs e);
    }

    public class SearchEventArgs : EventArgs
    {
        public SearchEventArgs() { }

        public string SearchValue { get; set; }
    }
}