display images in datalist which are not in database

<ItemTemplate>
< %#getSoldProductImages(Eval("CategoryId"))%>

</ItemTemplate>


protected string getSoldProductImages(object categoryId)
{
              Find all the soldout product image ref from database

StringBuilder strb=new StringBuilder() ;
      foreach(var img in imagelist)
{
    strb.append("< img src='path\"+img+"'>");
}
return strb.ToString()
}