ASP.NET Change facebook og properties from content page

Question

I want to dynamically change in code behind facebook og properties like

< meta property="og:image" content="image_link" />
< meta property="og:title" content="title" />

How to do this?

btw. I'm adding regular meta tags like this:

HtmlMeta tag = new HtmlMeta();
tag.Name = "description";
tag.Content = message;
Page.Header.Controls.Add(tag);

Solution 1

Here is how you add the proprietary Facebook "property" attribute to a standard META tag:

HtmlMeta tag = new HtmlMeta();
tag.Attributes.Add("property", "og:title");
tag.Content = "MyTitle"; // don't HtmlEncode() string. HtmlMeta already escapes characters.
Page.Header.Controls.Add(tag);

Solution 2

if what you want is to add a property attribute in c# to HtmlControl this should be like so:

tag.Attributes.Add(KEY, VALUE);  

where KEY = "property" and VALUE = "og:image"

hope this helps

Comments

[Josh Robinson]

doesn't work if you have code blocks <%%> in the header :(

[Doug S]

@JoshRobinson If you have <% %> code in the header, then just also hardcode the tag: <meta property="og:title" content="<%= HttpUtility.HtmlEncode(docTitle) %>" />. Of course, also set the docTitle variable in the code-behind or before that tag.

[Yannick Richard]

this is not working for me. Facebook crawler does not seems to read dynamically added meta tags

[Doug S]

@YannickRichard Facebook can't tell the difference between dynamically added meta tags or hardcoded meta tags. Facebook is just reading the HTML output. That means something else is wrong with your code.