RXX SelectMany

Question

.NET 4.0 and latest version of RXX (validated the dll was 4.0)

Took the lab example of this code:

 public void DownloadHtmlPageExperiment()
    {
      Uri address = UserInputUrl(Text.PromptFormat, Instructions.EnterAUrl);

      TraceLine(Text.Subscribing);
      TraceLine();

      using (var client = new WebClient())
      {
        var htmlTagsWithIds = client
          .DownloadStringObservable(address)
          .SelectMany(response =>
            Regex.Matches(
              response,
              @"\< (?<Tag> \w+? ) \s [^\>]*? id= (?<Q> [""']? ) (?<ID> .+? ) \k<Q> .*? \>",
                RegexOptions.IgnoreCase
              | RegexOptions.ExplicitCapture
              | RegexOptions.IgnorePatternWhitespace
              | RegexOptions.Singleline)
            .Cast<Match>())
          .Select(match => new
          {
            Tag = match.Groups["Tag"].Value,
            Id = match.Groups["ID"].Value
          });

        using (htmlTagsWithIds.Subscribe(ConsoleOutput))
        {
          TraceLine(Instructions.PressAnyKeyToCancel);

          WaitForKey();
        }
      }
    }

Chopped it up in my code to look like this:

  public void DownloadHtmlPageExperiment()
        {
            Uri address = new Uri("http://www.test.com");

            using (var client = new WebClient())
            {
                var htmlTagsWithIds = client                   
                  .DownloadStringObservable(address)
                 
                  .SelectMany(response =>
                    Regex.Matches(
                      response,
                      @"\< (?<Tag> \w+? ) \s [^\>]*? id= (?<Q> [""']? ) (?<ID> .+? ) \k<Q> .*? \>",
                        RegexOptions.IgnoreCase
                      | RegexOptions.ExplicitCapture
                      | RegexOptions.IgnorePatternWhitespace
                      | RegexOptions.Singleline)
                    .Cast<Match>())
                  .Select(match => new
                  {
                      Tag = match.Groups["Tag"].Value,
                      Id = match.Groups["ID"].Value
                  });
            }
        }

VS2010 is telling me there's no support of SelectMany<IObservable<string>>....  Can't compile example...

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JP Cowboy Coders Unite!

Answer 1

a) Did you make sure that the reactive extensions are properly referenced?

b) Do you have System.Reactive.Linq in your using statements?

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DevBiker (aka J Sawyer)
Microsoft MVP - Sql Server (StreamInsight)

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Answer 2

Thanks for response, I'll give it a second look once I reopen project... I set it aside after this issue, but now I have to find it... egad!

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JP Cowboy Coders Unite!

Answer 3

Hi,

As DevBiker wrote, you need to add a using directive to the top of your file:

using System.Reactive.Linq;

It's probably better to copy the entire lab, not just a portion of it.  Other using statements specified at the top of the lab may also be required.

- Dave

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http://davesexton.com/blog