Write HTML to string

Question

You're probably better off using an HtmlTextWriter or an XMLWriter than a plain StringWriter. They will take care of escaping for you, as well as making sure the document is well-formed.

This page shows the basics of using the HtmlTextWriter class, the gist of which being:

StringWriter stringWriter = new StringWriter();

using (HtmlTextWriter writer = new HtmlTextWriter(stringWriter))
{
    writer.AddAttribute(HtmlTextWriterAttribute.Class, classValue);
    writer.RenderBeginTag(HtmlTextWriterTag.Div); // Begin #1

    writer.AddAttribute(HtmlTextWriterAttribute.Href, urlValue);
    writer.RenderBeginTag(HtmlTextWriterTag.A); // Begin #2

    writer.AddAttribute(HtmlTextWriterAttribute.Src, imageValue);
    writer.AddAttribute(HtmlTextWriterAttribute.Width, "60");
    writer.AddAttribute(HtmlTextWriterAttribute.Height, "60");
    writer.AddAttribute(HtmlTextWriterAttribute.Alt, "");

    writer.RenderBeginTag(HtmlTextWriterTag.Img); // Begin #3
    writer.RenderEndTag(); // End #3

    writer.Write(word);

    writer.RenderEndTag(); // End #2
    writer.RenderEndTag(); // End #1
}
// Return the result.
return stringWriter.ToString();

When I deal with this problem in other languages I go for a separation of code and HTML. Something like:

1.) Create a HTML template. use [varname] placeholders to mark replaced/inserted content.
2.) Fill your template variables from an array or structure/mapping/dictionary

Write( FillTemplate(myHTMLTemplate, myVariables) ) # pseudo-code

Use an XDocument to create the DOM, then write it out using an XmlWriter. This will give you a wonderfully concise and readable notation as well as nicely formatted output.

Take this sample program:

using System.Xml;
using System.Xml.Linq;

class Program {
    static void Main() {
        var xDocument = new XDocument(
            new XDocumentType("html", null, null, null),
            new XElement("html",
                new XElement("head"),
                new XElement("body",
                    new XElement("p",
                        "This paragraph contains ", new XElement("b", "bold"), " text."
                    ),
                    new XElement("p",
                        "This paragraph has just plain text."
                    )
                )
            )
        );

        var settings = new XmlWriterSettings {
            OmitXmlDeclaration = true, Indent = true, IndentChars = "	"
        };
        using (var writer = XmlWriter.Create(@"C:\Users\wolf\Desktop	est.html", settings)) {
            xDocument.WriteTo(writer);
        }
    }
}

This generates the following output:

<!DOCTYPE html >
<html>
    <head />
    <body>
        <p>This paragraph contains <b>bold</b> text.</p>
        <p>This paragraph has just plain text.</p>
    </body>
</html>

I know you asked about C#, but if you're willing to use any .Net language then I highly recommend Visual Basic for this exact problem. Visual Basic has a feature called XML Literals that will allow you to write code like this.

Module Module1

    Sub Main()

        Dim myTitle = "Hello HTML"
        Dim myHTML = <html>
                         <head>
                             <title><%= myTitle %></title>
                         </head>
                         <body>
                             <h1>Welcome</h1>
                             <table>
                                 <tr><th>ID</th><th>Name</th></tr>
                                 <tr><td>1</td><td>CouldBeAVariable</td></tr>
                             </table>
                         </body>
                     </html>

        Console.WriteLine(myHTML)
    End Sub

End Module

This allows you to write straight HTML with expression holes in the old ASP style and makes your code super readable. Unfortunately this feature is not in C#, but you could write a single module in VB and add it as a reference to your C# project.

Writing in Visual Studio also allows proper indentation for most XML Literals and expression wholes. Indentation for the expression holes is better in VS2010.

return string.Format(@"<!DOCTYPE HTML PUBLIC ""-//W3C//DTD HTML 4.01//EN""      ""http://www.w3.org/TR/html4/strict.dtd"">
<html>
<title>{0}</title>
<link rel=""stylesheet"" type=""text/css"" href=""style.css"">
</head>
<body>
", title);

You could use System.Xml.Linq objects. They were totally redesigned from the old System.Xml days which made constructing XML from scratch really annoying.

Other than the doctype I guess, you could easily do something like:

var html = new XElement("html",
    new XElement("head",
        new XElement("title", "My Page")
    ),
    new XElement("body",
        "this is some text"
    )
);

The most straight forward way is to use an XmlWriter object. This can be used to produce valid HTML and will take care of all of the nasty escape sequences for you.

http://msdn.microsoft.com/en-us/library/system.xml.xmlwriter.aspx

Write HTML to string

Tags:

html

c#

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Write HTML to string

Tags:

html

c#

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