Web applications are dynamic- many requiring unique content and interfaces for each user. There are a myriad of ways to take user content out of a database and present it in a browser. This article focuses on the different ways it can be done in the Microsoft world (specifically in ASP.NET), why we chose XSLT for our own product, and finally a look at our technical implementation.

Planning for Dynamic Content

Whether you are in the process of building a new business web application or planning to build one, you most likely need to address how your web application will handle displaying different content for different users.

Considerations

When considering the different options for displaying dynamic content you generally need to take into account the following aspects:

• Usability
  Usability might be one of the most critical aspects in the success (or lack thereof) of your application.
• Development Time
  This includes the total amount of development time involved in satisfying your current application requirements.
• Flexibility
  Regardless of how comprehensive your current requirements are, applications tend to evolve over time. It’s important to evaluate the development effort and skill sets required to accommodate changes.
• Support, Maintenance & Ongoing Enhancements
  Commonly ignored by many when planning new development projects, it is generally responsible for a good chunk of the total cost of an application over the span of its life. This includes bug fixes, client customizations, minor application enhancements and of course, QA and testing.

The Options in ASP.NET

Generally web applications that use ASP.NET have two main options for displaying dynamic content:

• Server Controls
  • With Binding – retrieving the relevant data and binding it to the appropriate ASP.Net server controls on a web form
  • In Code – populating the appropriate ASP.Net server controls in code
• HTML
  • In Code – constructing the HTML to display in code based on the information retrieved from the database
  • With XSLT – retrieving the database information in XML format and then transforming it into HTML with XSLT

A third option is Silverlight, a new technology introduced as an option for web applications by Microsoft about a year ago. Silverlight provides a very rich GUI with the power of the .Net platform (a subset, actually) and tools that make web application development similar to the XAML interfaces found in the latest Windows application development. Silverlight is outside the scope of this particular article though.

Comparing the Different Options

Before you decide on the best route to take to display dynamic content you need to evaluate the impact of each approach on your application. You might find the table below helpful when making this decision.

Real-World Use Case: Scopings

When we started evaluating the requirements for Scopings, our homegrown recruiting platform, we needed a way to present complex content with a unique look and feel, a high level of usability, an infrastructure that can easily adapt to frequent and substantial changes, and built-in capabilities for globalization.

Very quickly we realized that although we can use ASP.Net server controls to build the first revision of Scopings in a relatively short period of time, this wouldn’t adapt well to the frequent changes we expected to be an inevitable part of the product lifecycle. This option would substantially increase our total cost of ownership.

After much analysis and many discussions, it became clear to us that designing our own infrastructure for constructing HTML using XML and XSLT would satisfy all of our requirements. We sat down and started to design an infrastructure that has ultimately been used for more than 80% of the functionality on Scopings.

Constructing the HTML

The idea behind the Scopings infrastructure was to allow us to make substantial changes to our user interface, while eliminating the need for any code changes and development staff involvement, and substantially decreasing the amount of QA required following any changes to the user interface.

To accommodate these requirements the Scopings infrastructure was built to be completely indifferent to the information retrieved from our database and to the way the information is ultimately displayed.

To achieve this we designed the infrastructure as follows:

<li>A separate stored procedure was built against each web content page to be displayed, and was designed to only return XML back to the calling code. </li>
<li>Upon loading a web page, the code behind would load the XML for the current user. The XSLT would then transform the XML to an HTML interface for the user. </li>
<li>The web page would be responsible for all functionality,<p class='post-footer'>
   original link:
   <a href='http://Apiaceae.github.io/blog/2009/03/27/%E7%BD%91%E7%BB%9C%E5%BA%94%E7%94%A8%E7%A8%8B%E5%BA%8F%E7%95%8C%E9%9D%A2%E5%BF%AB%E9%80%9F%E5%88%9B%E5%BB%BA/'>http://Apiaceae.github.io/blog/2009/03/27/%E7%BD%91%E7%BB%9C%E5%BA%94%E7%94%A8%E7%A8%8B%E5%BA%8F%E7%95%8C%E9%9D%A2%E5%BF%AB%E9%80%9F%E5%88%9B%E5%BB%BA/</a><br/>
   &nbsp;written by <a href='http://Apiaceae.github.io'>Hooker</a>
   &nbsp;posted at <a href='http://Apiaceae.github.io'>http://Apiaceae.github.io</a>
   </p>

original link: http://Apiaceae.github.io/blog/2009/03/27/%E5%90%8E%E5%88%86%E7%B1%BB%E5%AD%A6%E5%AE%B6%E7%9A%84%E6%97%B6%E4%BB%A3/
 written by Hooker  posted at http://Apiaceae.github.io

今天编译一些学习处理XML文档的代码，结果调试出现上图的错误。网络搜索的解决方案如下：

解决的方法是在命令行窗口(开始–运行–cmd)中输入“C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis.exe -i”。这样问题就解决了。发现，在原先在IIS>默认网站>属性>主目录>配置>映射应用程序映射中，比原先多出了许多扩展名，如我就需要运行了.aspx等，这样，在IIS中就注册完成了。
或者点开始–程序–Microsoft Visual Studio .net 2005–Visual Studio Tools–Visual Studio 命令提示行
在里面写aspnet_regiis.exe -i
重新注册IIS

不管用

 示例代码如下：

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
using System.Xml.XPath;

public partial class UpdateXML : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //Response.ContentType = "txt/xml";//错误的问题就出在这里，注释掉就好了。
        string xmlPath = Request.PhysicalApplicationPath + @"App_Data\Books.xml";
        XmlDocument document = new XmlDocument();
        document.Load(xmlPath);
        XPathNavigator navigator = document.CreateNavigator();
        int count = navigator.Select("/bookstore/book").Count;
        navigator.MoveToChild("bookstore", "");
        navigator.MoveToChild("book", "");
        for (int i = 0; i < count; i++)
        {
            navigator.MoveToChild("price", "");
            double discount = navigator.ValueAsDouble * (.1);
            navigator.CreateAttribute("","discount","",discount.ToString());
            navigator.MoveToParent();
            navigator.MoveToNext();
        }
        navigator.MoveToRoot();
        Response.Write(navigator.OuterXml);
    }
}

另外一段代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
using System.Xml.Schema;
using System.IO;

public partial class Default3 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //Response.ContentType = "text/xml";//注释掉也不管用，还是出现老问题
        string xmlFilePath = Request.PhysicalApplicationPath + @"App_Data\Authors.xml";
        XmlReader reader = XmlReader.Create(xmlFilePath);
        XmlSchemaSet schemaSet = new XmlSchemaSet();
        XmlSchemaInference schema = new XmlSchemaInference();
        schemaSet = schema.InferSchema(reader);
        foreach (XmlSchema schemaObj in schemaSet.Schemas())
        {
            schemaObj.Write(Response.Output);
        }
    }
}

original link: http://Apiaceae.github.io/blog/2009/03/27/XML%E6%98%BE%E7%A4%BA%E5%87%BA%E9%94%99/
 written by Hooker  posted at http://Apiaceae.github.io

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
using System.Xml.Schema;

public partial class ShowXpath : System.Web.UI.Page
{
    /// <summary>
    /// Handles the Load event of the Page control.
    /// </summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            ddlExpressions.Items.Add("//book/title");
            ddlExpressions.Items.Add("//book/[@genre='novel']/title");
            ddlExpressions.Items.Add("//book/author/first-name");
            ddlExpressions.Items.Add("//book/[@genre='philosophy']/title");
            ddlExpressions.Items.Add("//book/price");
            ddlExpressions.Items.Add("//book[3]/title");
            ddlExpressions.SelectedIndex = 0;
            UpdateDisplay();
        }

    }
    /// <summary>
    /// Handles the SelectedIndexChanged event of the ddlExpressions control.
    /// </summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
    protected void ddlExpressions_SelectedIndexChanged(object sender, EventArgs e)
    {
        UpdateDisplay();
    }
    /// <summary>
    /// Updates the display.
    /// </summary>
    void UpdateDisplay()
    {
        lstOutput.Items.Clear();
        string xmlFilePath = Request.PhysicalApplicationPath + @"App_Data\Books.xml";
        XmlDocument doc = new XmlDocument();
        doc.Load(xmlFilePath);
        XmlNodeList nodeList = doc.DocumentElement.SelectNodes(ddlExpressions.SelectedItem.Text);
        foreach (XmlNode child in nodeList)
        {
            lstOutput.Items.Add("Node name: " + child.Name);
            lstOutput.Items.Add("Node value: " + child.FirstChild.Value);
        }
 
    }
}

original link: http://Apiaceae.github.io/blog/2009/03/27/%E8%B0%83%E7%94%A8XPath%E6%98%BE%E7%A4%BAXML%E6%96%87%E6%A1%A3/
 written by Hooker  posted at http://Apiaceae.github.io

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;
using System.IO;

public partial class CreateXML : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnSave_Click(object sender, EventArgs e)
    {
        string xmlFilePath = Request.PhysicalApplicationPath + @"\App_Data\NewBooks.xml";
        XmlDocument doc = new XmlDocument();
        if (File.Exists(xmlFilePath))
        {
            doc.Load(xmlFilePath);
            XmlNode bookNode = CreateBookNode(doc);
            XmlNode bookStoreNode = doc.SelectSingleNode("bookstore");
            bookStoreNode.AppendChild(bookNode);
            lblResult.Text = "文件写入成功！";
        }
        else
        {
            XmlNode declarationNode = doc.CreateXmlDeclaration("1.0", "", "");
            doc.AppendChild(declarationNode);
            XmlComment comment = doc.CreateComment("这是一个测试性XML文档");
            doc.AppendChild(comment);

            XmlNode bookStoreNode = doc.CreateElement("bookstore");
            XmlNode bookNode = CreateBookNode(doc);

            bookStoreNode.AppendChild(bookNode);
            doc.AppendChild(bookStoreNode);

            lblResult.Text = "文件成功写入！";
        }
        doc.Save(xmlFilePath);
    }
    XmlNode CreateBookNode(XmlDocument doc)
    {
       
        XmlNode bookNode = doc.CreateElement("book");
        XmlAttribute genreAttribute = doc.CreateAttribute("genre");
        genreAttribute.Value = txtGenre.Text;
        bookNode.Attributes.Append(genreAttribute);

        XmlNode titleNode = doc.CreateElement("title");
        titleNode.InnerText = txtTitle.Text;
        bookNode.AppendChild(titleNode);

        XmlNode authorNode = doc.CreateElement("author");
        XmlNode firstNameNode = doc.CreateElement("first-name");
        firstNameNode.InnerText = txtFirstName.Text;
        authorNode.AppendChild(firstNameNode);

        XmlNode lastNameNode = doc.CreateElement("last-name");
        lastNameNode.InnerText = txtLastName.Text;
        authorNode.AppendChild(lastNameNode);

        bookNode.AppendChild(authorNode);

        XmlNode priceNode = doc.CreateElement("price");
        priceNode.InnerText = txtPrice.Text;
        bookNode.AppendChild(priceNode);

        return bookNode;
    }
    XmlNode CreateBookNodeFragment(XmlDocument doc)
    {
        XmlDocumentFragment docFragment = doc.CreateDocumentFragment();
        docFragment.InnerXml = "<book genre='" + txtGenre.Text + "'>" + "<title>" + txtTitle.Text + "</title>" + "<author><first-name>" + txtFirstName.Text + "</first-name>" + "<last-name>" + txtLastName.Text + "</last-name></author>" + "<price>" + txtPrice.Text + "</price></book>";
        return docFragment;

    }
}

original link: http://Apiaceae.github.io/blog/2009/03/27/%E5%88%9B%E5%BB%BAXML%E6%96%87%E6%A1%A3/
 written by Hooker  posted at http://Apiaceae.github.io

Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling.

Classic problems in historical biogeography are where did penguins originate, and why are such mobile birds restricted to the Southern Hemisphere?

Competing hypotheses posit they arose in tropical–warm temperate waters, species-diverse cool temperate regions, or in Gondwanaland w100 mya when it was further north.

To test these hypotheses we constructed a strongly supported phylogeny of extant penguins from 5851 bp of mitochondrial and nuclear DNA. Using Bayesian inference of ancestral areas we show that an Antarctic origin of extant taxa is highly likely, and that more derived taxa occur in lower latitudes. Molecular dating estimated penguins originated about 71 million years ago in Gondwanaland when it was further south and cooler.

Moreover, extant taxa are inferred to have originated in the Eocene, coincident with the extinction of the larger-bodied fossil taxa as global climate cooled. We hypothesize that, as Antarctica became ice-encrusted, modern penguins expanded via the circumpolar current to oceanic islands within the Antarctic Convergence, and later to the southern continents.

Thus, global cooling has had a major impact on penguin evolution, as it has on vertebrates generally. Penguins only reached cooler tropical waters in the Galapagos about 4 mya, and have not crossed the equatorial thermal barrier.

Keywords: penguins; divergence time; biogeography; nuclear DNA; mitochondrial DNA

original link: http://Apiaceae.github.io/blog/2009/03/27/phylogeography/
 written by Hooker  posted at http://Apiaceae.github.io

由于缺乏对植物物种长距离散布频度好的量化估计，我们对它们的分布在气候变化条件下的响应情况的理解受到很大限制。通过分析分布与北极岛屿和Svalbard及其邻近地区的9个有花植物种的超过4000个取样的遗传变异分析，Alsos等的研究表明，自从最后大大冰期以来，在Svalbard岛屿居群的建立过程中，长距离散布的种类来源于多个地区。因此，长距离散布现象比我们所通常认为的那样要普遍的多，这反过来也表明这些种类分布范围的向北转移可能在全球变暖后发生地相当快速。

original link: http://Apiaceae.github.io/blog/2009/03/26/biogeograph-ldd/
 written by Hooker  posted at http://Apiaceae.github.io

本来以为这也是经典的红皮书系列，但是当你真真读几章后会有种大失所望的感觉。主要原因是作者的叙述和写书的风格实在不敢恭维。太啰嗦，不该讲的讲了一大堆，当该仔细的讲代码的时候却又简略的让人有些晕，不知道实际如何动手。完全就是一本“纸上谈兵”的书，比较空洞。看起来花的时间和收获实在不能成正比啊。

original link: http://Apiaceae.github.io/blog/2009/03/26/ASP.NET+WebPart%E6%8E%A7%E4%BB%B6%E4%BB%8B%E7%BB%8D/
 written by Hooker  posted at http://Apiaceae.github.io

   original link:
   <a href='http://Apiaceae.github.io/blog/2009/03/25/ASP.NET%E7%BD%91%E7%AB%99%E7%AE%A1%E7%90%86%E5%B7%A5%E5%85%B7%E7%9A%84%E4%BD%BF%E7%94%A8/'>http://Apiaceae.github.io/blog/2009/03/25/ASP.NET%E7%BD%91%E7%AB%99%E7%AE%A1%E7%90%86%E5%B7%A5%E5%85%B7%E7%9A%84%E4%BD%BF%E7%94%A8/</a><br/>
   &nbsp;written by <a href='http://Apiaceae.github.io'>Hooker</a>
   &nbsp;posted at <a href='http://Apiaceae.github.io'>http://Apiaceae.github.io</a>
   </p>

original link: http://Apiaceae.github.io/blog/2009/03/25/Navicat%E8%B6%85%E5%BC%BA%E7%9A%84%E6%95%B0%E6%8D%AE%E6%A0%BC%E5%BC%8F%E8%BD%AC%E6%8D%A2%E5%92%8C%E5%A4%84%E7%90%86%E8%83%BD%E5%8A%9B/
 written by Hooker  posted at http://Apiaceae.github.io