.net c# 一個簡單但是功能強大動態模板引擎

 .net c# 一個簡單但是功能強大動態模板引擎(一) 收藏
      注意:歡迎轉載,但是請註明出處.

      流行的模板引擎有很多,譬如velocity.但是他的範本語言比較簡,複雜的功能比較難實現,而且編輯模板比較麻煩容易出錯.

      但是利用UserControl就可以實現功能強大的一個動態模板引擎,編輯的模板的時候跟編輯一個使用者控制項沒有區別,並且支援任何.net語言譬如c#.

      下面就是代碼:

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using System;  
using System.Collections.Generic;  
using System.Text;  
 
namespace Template  
{  
    public class TemplateBody : System.Web.UI.UserControl  
    {  
        private IDictionary<string, object> _context = new Dictionary<string, object>();  
        protected void Page_Load(object sender, EventArgs e)  
        {  
 
        }  
 
        public IDictionary<string, object> ViewData  
        {  
            get { return _context; }  
        }  
    }  
} 
using System;
using System.Collections.Generic;
using System.Text;

namespace Template
{
    public class TemplateBody : System.Web.UI.UserControl
    {
        private IDictionary<string, object> _context = new Dictionary<string, object>();
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        public IDictionary<string, object> ViewData
        {
            get { return _context; }
        }
    }
}

TemplateBody類基本沒什麼代碼只是聲明了一個ViewData屬性,該屬性用於向模板添加資料由模板來擷取並展示.

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using System;  
using System.Collections.Generic;  
using System.Text;  
using System.IO;  
using System.Web.UI;  
 
namespace Template  
{  
    public class TemplateEngine:IDisposable  
    {  
        private UserControl _uc;  
        private TemplateBody _tpl;  
 
        public TemplateEngine()  
        {  
            _uc = new UserControl();  
        }  
        /// <summary>  
        /// 載入一個模板  
        /// </summary>  
        /// <param name="path">這個路徑為相對路徑</param>  
        public void Load(string path)  
        {  
            _tpl = _uc.LoadControl(path) as TemplateBody;  
            if (_tpl == null)  
            {  
                throw (new ArgumentException(path));  
            }  
        }  
        /// <summary>  
        /// 控制展示  
        /// </summary>  
        /// <returns>返回產生的字串</returns>  
        public string Render()  
        {  
            TextWriter tw = new StringWriter();  
            Render(tw);  
            return tw.ToString();  
        }  
        /// <summary>  
        /// 展示模板  
        /// </summary>  
        /// <param name="writer">TextWriter對象,可以傳Response.Output</param>  
        public void Render(TextWriter writer)  
        {  
            HtmlTextWriter htw = new HtmlTextWriter(writer);  
            _tpl.RenderControl(htw);  
        }  
        /// <summary>  
        /// 增加一個顯示資料的上下文  
        /// </summary>  
        /// <param name="key"></param>  
        /// <param name="obj"></param>  
        public void AddContext(string key, object obj)  
        {  
            _tpl.ViewData.Add(key, obj);  
        }  
 
        public object this[string key]  
        {  
            get{  
                object ret;  
                _tpl.ViewData.TryGetValue(key, out ret);  
                return ret;  
            }  
            set { AddContext(key, value); }  
        }  
        public void Dispose()  
        {  
            Dispose(true);  
            GC.SuppressFinalize(this);  
        }  
        protected void Dispose(bool disposing)  
        {  
            if (disposing)  
            {  
                _uc.Dispose();  
            }  
    
        }  
        ~TemplateEngine()  
        {  
            Dispose(false);  
        }  
    }  
} 
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Web.UI;

namespace Template
{
    public class TemplateEngine:IDisposable
    {
        private UserControl _uc;
        private TemplateBody _tpl;

        public TemplateEngine()
        {
            _uc = new UserControl();
        }
        /// <summary>
        /// 載入一個模板
        /// </summary>
        /// <param name="path">這個路徑為相對路徑</param>
        public void Load(string path)
        {
            _tpl = _uc.LoadControl(path) as TemplateBody;
            if (_tpl == null)
            {
                throw (new ArgumentException(path));
            }
        }
        /// <summary>
        /// 控制展示
        /// </summary>
        /// <returns>返回產生的字串</returns>
        public string Render()
        {
            TextWriter tw = new StringWriter();
            Render(tw);
            return tw.ToString();
        }
        /// <summary>
        /// 展示模板
        /// </summary>
        /// <param name="writer">TextWriter對象,可以傳Response.Output</param>
        public void Render(TextWriter writer)
        {
            HtmlTextWriter htw = new HtmlTextWriter(writer);
            _tpl.RenderControl(htw);
        }
        /// <summary>
        /// 增加一個顯示資料的上下文
        /// </summary>
        /// <param name="key"></param>
        /// <param name="obj"></param>
        public void AddContext(string key, object obj)
        {
            _tpl.ViewData.Add(key, obj);
        }

        public object this[string key]
        {
            get{
                object ret;
                _tpl.ViewData.TryGetValue(key, out ret);
                return ret;
            }
            set { AddContext(key, value); }
        }
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
        protected void Dispose(bool disposing)
        {
            if (disposing)
            {
                _uc.Dispose();
            }
 
        }
        ~TemplateEngine()
        {
            Dispose(false);
        }
    }
}
 

TemplateEngine 是負責顯示的類,核心代碼也就是調用了RenderControl函數.

下面是具體使用:

1.建立一個web工程,注意其他工程可能不支援.

2.添加預設頁面Default.aspx

3.根目錄添加一個TemplateTest.ascx的模板檔案 副檔名預設是ascx,如果需要更改別的副檔名的話需要在web.config裡在compilation節點增加下列代碼:

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<buildProviders>   
  <add extension=".view" type="System.Web.Compilation.UserControlBuildProvider"/> 
</buildProviders> 
      <buildProviders>
        <add extension=".view" type="System.Web.Compilation.UserControlBuildProvider"/>
      </buildProviders>

4.直接運行就可以.

Default.aspx代碼:

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using System;  
using System.Collections;  
using System.Configuration;  
using System.Data;  
using System.Web;  
using System.Web.Security;  
using System.Web.UI;  
using System.Web.UI.HtmlControls;  
using System.Web.UI.WebControls;  
using System.Web.UI.WebControls.WebParts;  
 
using Template;  
 
namespace TemplateDemo  
{  
    public partial class _Default : System.Web.UI.Page  
    {  
        protected void Page_Load(object sender, EventArgs e)  
        {  
           TemplateEngine te = new TemplateEngine();  
           te.Load("TemplateTest.ascx");  
           te.AddContext("Text", "Super Man");  
           te.Render(Response.Output);  
        }  
    }  
} 
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

using Template;

namespace TemplateDemo
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
           TemplateEngine te = new TemplateEngine();
           te.Load("TemplateTest.ascx");
           te.AddContext("Text", "Super Man");
           te.Render(Response.Output);
        }
    }
}

 TemplateTest.ascx代碼:

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<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="TemplateBody.cs" Inherits="Template.TemplateBody" %>  
 
 
<% for (int i = 0; i < 10; i++){  
   %>  
<%=ViewData["Text"]%>  
<% }%> 
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="TemplateBody.cs" Inherits="Template.TemplateBody" %>

<% for (int i = 0; i < 10; i++){
   %>
<%=ViewData["Text"]%>
<% }%> 

記住,模板必須要加這個頭:

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="TemplateBody.cs" Inherits="Template.TemplateBody" %>

下面是顯示結果:

 Super Man Super Man Super Man Super Man Super Man Super Man Super Man Super Man Super Man Super Man

需要改進的地方:

目前模板只支援相對路徑,因為.net他對檔案進行緩衝處理,這樣運行一次模板後即編譯模板並進行緩衝,如果檔案被更改將重新編譯,提高效率.

如果您需要從資料庫或者從一個Stream裡載入模板的話,需要重寫VirtualPathProvide,並且重寫判斷模板被更改的函數CacheDependency,還有擷取虛擬檔案的函數GetFile, 這樣很容易實現從任何地方擷取模板.如果您有興趣可以進行改進,完善.

 

本文來自CSDN部落格，轉載請標明出處：http://blog.csdn.net/baoaya/archive/2009/07/27/4384178.aspx