JoshSalwen.com

I highly recommend watching (or at least listening to) the Warren Buffett interview with Charlie Rose.

A bit about me:

• I am web developer
• I am a .NET developer (ASP.NET, C#, VB)
• I am a Web Standards freak

OK, those last two don’t go very well together, and that has been my cross to bear.

For years, I have been looking for an open source ASP.NET CMS/blogging engine that I could use for myself and for other small websites. The catch was it had to adhere to Web Standards (valid XHTML 1.0 Strict markup, CSS for layout, etc). I found a few that sort of worked and I even wrote a few custom ones myself, but I was never satisfied.

Well, I give up.

For the last few months, I have been working on the website for my son’s (now former — he started kindergarten on Wednesday) preschool. As usual, I had no problem getting the site working using ASP.NET (everything validated, cleanish CSS), BUT I hadn’t tackled how I was going to handle the CMS.

I started down the road of using the MVC pattern in ASP.NET 3.5 with the help of Chris Tavares’ article, Building Web Apps without Web Forms. But then …

While attending Kelly Goto’s presentation at (the best conference I’ve yet attended) An Event Apart in San Francisco, she made an offhand comment about creating a website for her mom. She talked about simply getting WordPress up and running for her mom in about 15 minutes, and letting her mom take over. Preso … a website.

Now, I don’t know much about WordPress or PHP or MySql, but if Kelly’s mom can do it …

I then spent the next few evening doing some pilot projects to see how easy or hard it would be to get WordPress to act more like a CMS, and I’m converted. So far I haven’t found any gotchas that will prevent me from using WordPress for smaller websites. And even giving my handicap of not knowing PHP, it has been easier to write themes for WordPress than it would have been to write my own CMS in ASP.NET.

The Problem

I was recently looking for a way to programmatically add and update Meta Tags in ASP.NET 2.0. This is a fairly simple thing to do with standard .aspx pages. Just add ID and Runat attributes to the Head element and reference the control in the code behind. However, this is not so simple when working with MasterPages, which I am. What I wanted was a way to:

• Add a new Meta tag
• Change the content attribute of an existing Meta Tag
• Append data into the content attribute of an existing Meta Tag
• Do any of the above from a MasterPage, Page or User Control

AddMetaTag Utility in App_Code

Initially, in my Master Pages I added a AddMetaTag method, which the Content Pages could call. However, this did not allow me to call the method from User Controls. It was also a maintenance pain, since the code had to be added to each Master Page.

A simple solution was to take advantage of the App_Code folder and add a Utility Class, which could be called from anywhere in the Web project. The AddMetaTag method needs three parameters passed, the Page reference and strings for the Name and Content attributes of the Meta Tag.

C#

Utilities.cs (in App_Code)

public class Utilities {
  public static void AddMetaTag(Page thisPage, string name, string content) {
    ...
  }
}

Default.aspx.cs

protected void Page_Load(object sender, EventArgs e) {
  Utilities.AddMetaTag(this.Page, "author", "Josh Salwen");
}

VB

Utilities.vb (in App_Code)

Public Class Utilities
  Public Shared Sub AddMetaTag(ByVal thisPage As Page, ByVal name As String, ByVal content As String)
    ...
  End Sub
End Class

Default.aspx.vb

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  Utilities.AddMetaTag(Me.Page, "author", "Josh Salwen")
End Sub

Adding a New Meta Tag

Using the System.Web.UI.HtmlControls.HtmlMeta class makes it easy to create a Meta Tag.

C#

HtmlMeta meta = new HtmlMeta();
meta.Name = "Author";
meta.Content = "Josh Salwen";

VB

Dim meta As New HtmlMeta
meta.Name = "Author"
meta.Content = "Josh Salwen"

The trick is adding it into the HTML Head element.

By default, Visual Studio 2005 adds a runat="server" to the Head element in both .master pages and .aspx pages (if it is not a content page which references a Master Page). As long as the runat="server" is not removed, the Page.Header property can be accessed. If it is removed, then it is not possible to access the Page.Header, so when referencing the Header is is important to make sure it is not null (or Nothing).

Once the Page.Header is referenced, then you create a new HtmlMeta object and add it to the Page.Header Controls.

C#

public static void AddMetaTag(Page thisPage, String name, String content) {
  HtmlHead header = (HtmlHead)thisPage.Header;
  if (header != null) {
    HtmlMeta meta = new HtmlMeta();
    meta.Name = name;
    meta.Content = content;
    header.Controls.Add(meta);
  }
}

VB

Public Shared Sub AddMetaTag(ByVal thisPage As Page, ByVal name As String, ByVal content As String)
  Dim header As HtmlHead = DirectCast(thisPage.Header, HtmlHead)
  If Not IsNothing(header) Then
    Dim meta As New HtmlMeta
    meta.Name = name
    meta.Content = content
    header.Controls.Add(meta)
  End If
End Sub

Updating an Existing Meta Tag

Once the functionality was in place to add a Meta Tag, I just needed to add the ability to update an existing tag. In order to do this, the method does the following:

• Loops through the Controls in the Header
• Checks if the Control is an HtmlMeta
• Checks if the Name attributes are the same
• Updates the Content attribute and exits the method

C#

public static void AddMetaTag(Page thisPage, String name, String content) {
  HtmlHead header = (HtmlHead)thisPage.Header;
  if (header != null) {
    HtmlMeta meta = new HtmlMeta();
    // Loop through all the controls in the Header
    foreach (Control ctrl in header.Controls) {
      // Check if the control is a Meta Tag
      if (ctrl is HtmlMeta) {
        // Get the Meta Tag and check if the name is the same
        meta = (HtmlMeta)ctrl;
        if (name.Equals(meta.Name, StringComparison.InvariantCultureIgnoreCase)) {
          // Since the Meta Tag already exists, simply update and exit
          meta.Content = content;
          return;
        }
      }
    }
    meta = new HtmlMeta();
    meta.Name = name;
    meta.Content = content;
    header.Controls.Add(meta);
  }
}

VB

Public Shared Sub AddMetaTag(ByVal thisPage As Page, ByVal name As String, ByVal content As String)
  Dim header As HtmlHead = DirectCast(thisPage.Header, HtmlHead)
  If Not IsNothing(header) Then
    Dim meta As New HtmlMeta

    ' Loop through all the controls in the Header
    For Each ctrl as Control in header.Controls
      ' Check if the control is a Meta Tag
      If TypeOf ctrl Is HtmlMeta Then
        ' Get the Meta Tag and check if the name is the same
        meta = DirectCast(ctrl, HtmlMeta)
        If name.Equals(meta.Name, StringComparison.InvariantCultureIgnoreCase) Then
          ' Since the Meta Tag already exists, simply update and exit
          meta.Content = content
          Return
        End If
      End If
    Next
    meta = New HtmlMeta
    meta.Name = name
    meta.Content = content
    header.Controls.Add(meta)
  End If
End Sub

… And a Few More Things

I noted above that I want to be able to append data as well. I also want to compare the Name and Lang attributes, since you can add the same Meta Tag for different languages. I have included this code in the source code, if you want to check it out.

And finally, in the ASP.NET 2.0 Alpha, the Header had MetaData.Add (I think that is what it was called), so Microsoft was thinking about this at one point. I’m not sure what happened.