create an XML file that contains the data for the meta tags. Right click the website and choose Add > New Item > XML File. Name the file TagData.xml and add the following XML:
<tags pageName="/WebForm1.aspx">
<tag name="keyword" value="This is a keyword"></tag>
<tag name="description" value="This is a description"></tag>
<tag name="author" value="malcolm sheridan"></tag>
</tags>
<tags pageName="/ChildFolder/WebForm1.aspx">
<tag name="keyword" value="This is a keyword for the child pages"></tag>
<tag name="description" value="This is a description for the child pages"></tag>
<tag name="author" value="malcolm sheridan for this page too"></tag>
</tags>
In the XML above I have created a parent node called metaTags. Inside I have created a tags node which contains a pageName attribute. That value is how we will match the current requested page to the XML data. Each tags node contains a tag node that corresponds to the meta data we want sent to the browser. In this example I want to set meta tags for the all the pages to have keyword, description and author meta tags, but the values rendered to the browser will differ depending on what page the user is on. In a real world scenario this information would be stored inside a database, but I decided to keep this data inside an XML file to keep it simple and focus on how to do this.
Having outlined what meta tags we want sent to the browser, we now have to write the code that will read the XML file and dynamically add the meta tags at runtime. Seeing as though we’re using Master Pages this is the ideal spot to add it. Add the following code to read the XML file:
C#
XDocument doc = XDocument.Load(Server.MapPath("~/TagData.xml"));
var metaTags = doc.Descendants("tag")
.Where(o => o.Parent.Attribute("pageName").Value == Request.Url.AbsolutePath)
.Select(o => new
{
Value = o.Attribute("value").Value,
Name = o.Attribute("name").Value
});
VB.NET
Dim doc As XDocument = XDocument.Load(Server.MapPath("~/TagData.xml"))
Dim metaTags = doc.Descendants("tag").Where(Function(o) o.Parent.Attribute("pageName").Value = Request.Url.AbsolutePath).Select(Function(o) New With {Key .Value = o.Attribute("value").Value, Key .Name = o.Attribute("name").Value})
For flexibility and ease of use I have decided to use the power of LINQ to XML to read the XML data. To start with the XML document is load into an XDocument object. From there I have created a LINQ query to return all the tag nodes where the parent node has an attribute called pageName and the value is equal to the current page. Then the object returned is an anonymous type that has a Value and Name property. The values of those properties are the value and name attribute values.
Now that we have the data in memory, the next step is to create the meta tag and add it to the page dynamically. To do this you use the HtmlMeta class. This allows you programmatic access to the HTML meta tags. Add the following code below to your project:
C#
foreach (var item in metaTags)
{
HtmlMeta meta = new HtmlMeta();
meta.Name = item.Name;
meta.Content = item.Value;
Page.Header.Controls.Add(meta);
}
VB.NET
For Each item In metaTags
Dim meta As New HtmlMeta()
meta.Name = item.Name
meta.Content = item.Value
Page.Header.Controls.Add(meta)
Next item
The foreach loop enumerates through each item returned from the LINQ query. It assigns the Name and Content value to the HtmlMeta object. Finally the object is added to the page by calling Page.Header.Controls.Add(meta). Run the project and once the default page has loaded
