HtmlGenericControl("br") rendering twice

I'm adding some content to a given web page from code behind. When I want to add a break after some text, I try to do that this way:

pDoc.Controls.Add(New Label With {.Text = "whatever"})
pDoc.Controls.Add(New HtmlGenericControl("br"))

,where pDoc is the Panel in which I'm adding the content. But it adds two br tags into the final HTML.

I've avoid this behaviour this way:

pDoc.Controls.Add(New Label With {.Text = "whatever" & "<br />"})

Anyway, I'm so curious and I want to know why

pDoc.Controls.Add(New HtmlGenericControl("br"))

is acting that way. I also think my approach is not too fancy.

Regards,

Solution

After some testing it looks like the reason is that HtmlGenericControl doesn't support self closing. On server side the HtmlGenericControl("br") is treated as:

<br runat="server"></br>

There is no </br> tag in HTML, so the browser shows it as there are two <br /> tags. Nice way out of this is to create HtmlGenericSelfCloseControl like this (sorry for C# code but you should have no issue with rewritting this in VB.NET):

public class HtmlGenericSelfCloseControl : HtmlGenericControl
{
    public HtmlGenericSelfCloseControl()
        : base()
    {
    }

    public HtmlGenericSelfCloseControl(string tag)
        : base(tag)
    {
    }

    protected override void Render(HtmlTextWriter writer)
    {
        writer.Write(HtmlTextWriter.TagLeftChar + this.TagName);
        Attributes.Render(writer);
        writer.Write(HtmlTextWriter.SelfClosingTagEnd);
    }

    public override ControlCollection Controls
    {
        get { throw new Exception("Self closing tag can't have child controls"); }
    }

    public override string InnerHtml
    {
        get { return String.Empty; }
        set { throw new Exception("Self closing tag can't have inner content"); }
    }

    public override string InnerText
    {
        get { return String.Empty; }
        set { throw new Exception("Self closing tag can't have inner text"); }
    }
}

And use it instead:

pDoc.Controls.Add(New Label With {.Text = "whatever"})
pDoc.Controls.Add(New HtmlGenericSelfCloseControl("br"))

As a simpler alternative (if you have reference to the Page) you can try using Page.ParseControl:

pDoc.Controls.Add(New Label With {.Text = "whatever"})
pDoc.Controls.Add(Page.ParseControl("br"))