Question

I have a simple Windows service, which runs only once per day. It performs some queries in database, generates appropriate html content (tables, divs, …) and sends it in body of an e-mail to multiple recipients.

The body of the e-mail is created like this:

private static string GenerateBody()
{
    using (var stringWriter = new StringWriter())
    using (var htmlWriter = new HtmlTextWriter(stringWriter))
    {
        htmlWriter.RenderBeginTag("html");
        htmlWriter.RenderBeginTag(HtmlTextWriterTag.Head);
        htmlWriter.WriteLine("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />");
        htmlWriter.RenderEndTag();
        htmlWriter.RenderBeginTag("body");

        htmlWriter.Write(
            new StringBuilder()
                .Append(OverviewParagraph.GenerateHTMLContent())
                .Append(PackageWeightParagraph.GenerateHTMLContent())
                .Append(BoxWeightParagraph.GenerateHTMLContent())
                .Append(CodeQualityParagraph.GenerateHTMLContent())
                .Append(ChecksParagraph.GenerateHTMLContent())
                .ToString()
        );

        htmlWriter.RenderEndTag();
        htmlWriter.RenderEndTag();

        return stringWriter.ToString();
    }
}

All the GenerateHTMLContent methods are pretty much the same – they execute a query in my database, build an HTML table with the help of a HTMLTextWriter and return the table as a string.

Can this code be improved with the use of multithreading or maybe async-await pattern? The code in question is where I append lines to the StringBuilder object.

EDIT: I asked the question because I never worked with multithreading before, just wanted to know if it is possible. Besides, the program runs fast enough now.

Answer 1

StringBuilder sb = new StringBuilder();
Parallel.Invoke(
    () => { var s = OverviewParagraph.GenerateHTMLContent(); lock (sb) sb.Append(s); },
    () => { var s = PackageWeightParagraph.GenerateHTMLContent(); lock (sb) sb.Append(s); },
    () => { var s = BoxWeightParagraph.GenerateHTMLContent(); lock (sb) sb.Append(s); },
    () => { var s = CodeQualityParagraph.GenerateHTMLContent(); lock (sb) sb.Append(s); },
    () => { var s = CodeQualityParagraph.GenerateHTMLContent(); lock (sb) sb.Append(s); }
);