Adding meta tag programmatically in C#

Question

I'm trying to programmatically add a <meta>. It is working fine when there is a Head element with runat = "server" in the .aspx page.

The code behind is:

HtmlMeta meta = new HtmlMeta();
meta.Name = "robots";
meta.Content = "noindex,follow";
this.Page.Header.Controls.Add(meta);

But I have some script in the head tag which contains code blocks like <% ... %>, so I cannot keep the runat = "server" value.

The problem is I have to add the meta tag programmatically, because it depends on a value from the database.

Is there a way to solve this issue so that my script inside the head element works as usual and I can add a meta tag programmatically?

Community · Accepted Answer · 2017-05-23 11:46:51Z

43

OK, I tested the answer by veggerby, and it works perfectly:

In the <header> section:

<asp:PlaceHolder id="MetaPlaceHolder" runat="server" />

Note that Visual Studio might show a warning on the PlaceHolder tag, because it is not recognised as a known element inside the header, but you can ignore this. It works.

In the C# code:

HtmlMeta meta = new HtmlMeta();
meta.Name = "robots";
meta.Content = "noindex,follow";
MetaPlaceHolder.Controls.Add(meta);

Alternatively (since you already have code blocks using <% %> in your header section), you can tag the meta directly and retrieve only the value from server side:

<meta name="robots" content="<%=GetMetaRobotsValueFromDatabase()%>" />

edited May 23, 2017 at 11:46

CommunityBot

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answered Sep 16, 2009 at 11:59

awe

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1 Comment

Jonathan Williams Over a year ago

Apologies - The code was too long to post as a comment so I added an answer (using your code) below. Many thanks!

Community · Accepted Answer · 2017-05-23 12:25:52Z

Many thanks to Awe for the solution! I have implemented this code in a (error404.ascx) ASP.NET User Control as follows:

<%@ Control Language="C#"%>
<script runat="server">
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.TrySkipIisCustomErrors = true;  //Suppress IIS7 custom errors
        Response.StatusCode = 404;
        SetRobotsHeaderMetadata();
    }

    private void SetRobotsHeaderMetadata()
    {
        HtmlMeta meta = new HtmlMeta();
        meta.Name = "robots";
        meta.Content = "noindex,follow";
        this.Page.Master.FindControl("cphPageMetaData").Controls.Add(meta);
    }
</script>

With the following masterpage:

<%@ Master Language="C#" AutoEventWireup="true" Inherits="MyMaster" %>
<script runat="server">
    ...
</script>

<!DOCTYPE html>
<html lang="en-GB">
    <head>
        <title>Site title here</title>

        <asp:contentplaceholder runat="server" id="cphPageMetaData">
        </asp:contentplaceholder>
    </head>

    <body>
        ...
    </body>
</html>

SmartDev · Accepted Answer · 2014-03-06 21:49:35Z

7

I think this is the best approach:

this.Page.Header.Controls.Add(new LiteralControl(@"<meta ... />"));

Enjoy!

answered Mar 6, 2014 at 21:49

SmartDev

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2 Comments

Marie Over a year ago

I know it is a bit late but is there any reason you chose to use a LiteralControl over an HtmlMeta?

Marie Over a year ago

Additionally I dont think this answers the OPs question since the Header is not a server control. Page.Header will be null

Timothy Khouri · Accepted Answer · 2009-09-16 11:49:46Z

6

Or you could just put your meta-tag in the header, with an ID and a runat="server"... then in the code behind say

myMetaTag.Content = "noindex,follow";

or

myMetaTag.Visible = false;

or whatever you'd like.

answered Sep 16, 2009 at 11:49

Timothy Khouri

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Comments

Mike · Accepted Answer · 2009-09-16 11:39:16Z

5

Try moving whatever it is that you are doing in the <% .... %> to the code-behind. If you are using the script to add content into the page, you can replace it with an asp:Literal control and then set the value you were previously calculating in the script block to the code-behind and set Literal.Text to that value.

answered Sep 16, 2009 at 11:39

Mike

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Comments

Peter Mortensen · Accepted Answer · 2016-12-09 17:55:57Z

2

I haven't tested it, but maybe you can add an <asp:Placeholder> inside the <head></head> tag and add the meta tags to this.

edited Dec 9, 2016 at 17:55

Peter Mortensen

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answered Sep 16, 2009 at 11:39

veggerby

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Comments

Peter Mortensen · Accepted Answer · 2016-12-09 17:59:30Z

0

The best solution for this, which I successfully checked without any error or warning:

The JavaScript code, which contains the <% ... %> code, was removed from the head section and placed in the body section.

edited Dec 9, 2016 at 17:59

Peter Mortensen

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answered Mar 19, 2013 at 10:08

hemantrautela

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Comments

Peter Mortensen · Accepted Answer · 2016-12-09 18:01:32Z

0

You could define your meta tag as a static string like so:

Private Shared MetaLanguage As String =
    String.Format("<meta http-equiv=""Content-Language"" content=""{0}""/>", CultureInfo.CurrentUICulture.TwoLetterISOLanguageName)

Then place them in your head like so:

<head runat="server">
    <%=MetaLanguage%>
</head>

This allow you to use any meta tag values and is easy to read and customize. Note: The use of the Shared keyword (static) helps improve performance.

edited Dec 9, 2016 at 18:01

Peter Mortensen

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answered Apr 12, 2013 at 13:31

George Filippakos

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Comments

Nathan · Accepted Answer · 2013-05-26 12:15:29Z

-3

MetaDescription = "Your meta description goes here"; MetaKeywords = "Keyword1,Keyword2,Keyword3";

answered May 26, 2013 at 12:15

Nathan

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Comments

Peter Mortensen · Accepted Answer · 2016-12-09 18:03:06Z

-3

OK... I actually only use C#... Or HTML into C#. I never use codebehind, designer or webcontrols in the file aspx... So I program everything from classes... And dynamically.

Result:

HtmlMeta meta = new HtmlMeta();
meta.Name = "robots";
`meta.Content = "Here is what you want";`
var page=HttpContext.Current.Handler as Page;
page.Header.Controls.Add(meta);

edited Dec 9, 2016 at 18:03

Peter Mortensen

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answered Dec 18, 2014 at 19:37

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