Stop asp:PlaceHolder from removing whitespaces

Question

I came across some strange behavior of asp:PlaceHolder, it removes whitespaces between the asp:Literals within it.

For example for this code:

<asp:PlaceHolder ID="PlaceHolder1" runat="server">
    <asp:Literal ID="Literal1" Text="aa" runat="server"></asp:Literal>
    <asp:Literal ID="Literal2" Text="bb" runat="server"></asp:Literal>
</asp:PlaceHolder>
<asp:Literal ID="Literal3" Text="cc" runat="server"></asp:Literal>
<asp:Literal ID="Literal4" Text="dd" runat="server"></asp:Literal>

The output will be aabb cc dd.

Is there is a way to stop it from removing the whitespaces (and not by adding   between the literals or Text="aa ")?

Answer 1

The most elegant solution is to simply override PlaceHolder:

using System.Web.UI;
using System.Web.UI.WebControls;

namespace CustomControls
{
    [ToolboxData("<{0}:Holder ID='Holder1' runat='server'></{0}:Holder>"), ControlBuilder(typeof(ControlBuilder))]
    public sealed class Holder: PlaceHolder
    {
    }
}

The key here is using ControlBuilder instead of PlaceHolderControlBuilder, which just overrides it to always return false for AllowWhiteSpaceLiterals.

You use it as any other web control:

<%@ Register TagPrefix="asp" Namespace="CustomControls" %>
<asp:Holder runat="server">...</asp:Holder>

Answer 2

I came up with two solutions:

First: To replace the asp:PlaceHolder with asp:Panel. The disadvantage is that you get a wrapping div.

Second: To put an empty HTML comment between the literals

<asp:PlaceHolder ID="PlaceHolder1" runat="server">
    <asp:Literal ID="Literal1" Text="aa" runat="server"></asp:Literal><!>
    <asp:Literal ID="Literal2" Text="bb" runat="server"></asp:Literal>
</asp:PlaceHolder>

And yes, <!> is a legal HTML comment.