The Controls collection cannot be modified because the control contains code blocks i e

Question

I am trying to create dynamic meta tags in C  but it gives the following error      The Controls collection cannot be modified because the control   contains code blocks  i e   lt             This is the code I added   HtmlMeta meta   new HtmlMeta    meta Name    keywords   meta Content    book paper   Page Header Controls Add meta     Thank you very much

User · Answer

Not really solve your question but it s an important alternative   If you want to add custom html to the beginning of the page  inside  lt body gt  element   you may use Page ClientScript RegisterClientScriptBlock     Although the method is called  script   but you can add arbitary string  including html

User · Answer

It s hard to tell for sure because you haven t included many details  but I think what is going on is that there are  lt         gt  code blocks inside your Page Header  which is referring to  lt head runat  server  gt  - possibly in a master page   Therefore  when you try to add an item to the Controls collection of that control  you get the error message in the title of this question   If I m right  then the workaround is to wrap a  lt asp placeholder runat  server  gt  tag around the  lt         gt  code block  This makes the code block a child of the Placeholder control  instead of being a direct child of the Page Header control  but it doesn t change the rendered output at all  Now that the code block is not a direct child of Page Header you can add things to the header s controls collection without error   Again  there is a code block somewhere or you wouldn t be seeing this error  If it s not in your aspx page  then the first place I would look is the file referenced by the MasterPageFile attribute at the top of your aspx

User · Answer

Just in case if you are using Telerik components and you have a reference in your javascript with  lt            then wrap your script tag with a RadScriptBlock      lt telerik RadScriptBlock ID  radSript1  runat  server  gt      lt script type  text javascript  gt            Your javascript     lt  script gt   lt  telerik gt    Regards   rvar

User · Answer

Check out the solutions at  quot The Controls collection cannot be modified because the control contains code blocks quot   The accepted solution on the other question worked for me -- change instances of  lt    to  lt     which converts the code block from Response Write to an evaluation block  which isn t restricted by the same limitations   In this case though  like the accepted solution here suggests  you should add the controls to something other than a masterpage ContentPlaceHolder element  namely the asp Placeholder control suggested

User · Answer

I have had the same issue that I solved this way   Instead of adding the meta to the current page header that caused the same error as you had   Page Header Controls Add meta     I used this instead    Master FindControl  YourHeadContentPlaceHolder   Controls Add meta     and it works like a charm

User · Answer

For those using Telerik as mentioned by Ovar  make sure you wrap your javascript in         lt telerik RadScriptBlock ID  radSript1  runat  server  gt      lt script type  text javascript  gt            Your javascript     lt  script gt   lt  telerik gt    Since Telerik doesn t recognize  lt       when looking for an element and  lt       will give you an error if your javascript code isn t wrapped

User · Answer

Inside ContentPlaceholder  put the placeholder control For Example like this    lt asp Content ID  header  ContentPlaceHolderID  head  runat  server  gt          lt asp PlaceHolder ID  metatags  runat  server  gt           lt  asp PlaceHolder gt   lt  asp Content gt    Code Behind   HtmlMeta hm1   new HtmlMeta    hm1 Name    Description   hm1 Content    Content here   metatags Controls Add hm1

[c#] The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>)

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