Run-time Error for adding attribute in html meta tag

Question

Here is my code:

 public partial class Image : System.Web.UI.Page {
     protected void Page_Load(object sender, EventArgs e)
     {
         HtmlMeta tag = new HtmlMeta();
         tag.Attributes.Add("property", "og:type");
         Header.Controls.Add(tag);
     }
}

This is my error:

Server Error in '/Kidzania' Application. Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 18:         HtmlMeta tag = new HtmlMeta(); 
Line 19:         tag.Attributes.Add("property", "og:type"); 
Line 20:         Header.Controls.Add(tag);

Source File: d:\Kidzania\Image.aspx.cs Line: 20

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] Image.Page_Load(Object sender, EventArgs e) in d:\Kidzania\Image.aspx.cs:20
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +50
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

i am refer all stackoverflow answer but not solve that problem please any help to assisted me please. thanks in advance for your answers

bdoshi bdoshi · Accepted Answer · 2012-06-26T18:14:57

This how I think it will work.

HtmlMeta htmmeta = new HtmlMeta();
htmmeta.Attributes.Add("property", "og:type");
this.Header.Controls.Add(htmmeta);

Also you need to make sure that in your mark up header tag has runat server.

<head runat="server">

Run-time Error for adding attribute in html meta tag

1 Answers