How to extract a rar file in C#?

Question

I want to extract .rar files using cmd shell so I wrote this code:

string commandLine = @"c:\progra~1\winrar\winrar e  c:\download\TestedU.rar c:\download";
ProcessStartInfo PSI = new ProcessStartInfo("cmd.exe");
PSI.RedirectStandardInput = true;
PSI.RedirectStandardOutput = true;
PSI.RedirectStandardError = true;
PSI.UseShellExecute = false;
Process p = Process.Start(PSI);
StreamWriter SW = p.StandardInput;
StreamReader SR = p.StandardOutput;
SW.WriteLine(commandLine);
SW.Close(); 

The first time it worked fine, the second time it displayed nothing.

Answer 1

Use SevenZipSharp as it's a bit better way of doing things then working with some .exe's.

private ReadOnlyCollection<string> ExtractArchive(string varPathToFile, string varDestinationDirectory) {
        ReadOnlyCollection<string> readOnlyArchiveFilenames;
        ReadOnlyCollection<string> readOnlyVolumeFilenames;
        varExtractionFinished = false;
        varExtractionFailed = false;
        SevenZipExtractor.SetLibraryPath(sevenZipDll);
        string fileName = "";
        string directory = "";
        Invoke(new SetNoArgsDelegate(() => {
                                         fileName = varPathToFile;
                                         directory = varDestinationDirectory;
                                     }));
        using (SevenZipExtractor extr = new SevenZipExtractor(fileName)) {
            //string[] test = extr.ArchiveFileNames.

            readOnlyArchiveFilenames = extr.ArchiveFileNames;
            readOnlyVolumeFilenames = extr.VolumeFileNames;
            //foreach (string dinosaur in readOnlyDinosaurs) {
            //MessageBox.Show(dinosaur);
            // }
            //foreach (string dinosaur in readOnlyDinosaurs1) {
            // // MessageBox.Show(dinosaur);
            // }
            try {
            extr.Extracting += extr_Extracting;
            extr.FileExtractionStarted += extr_FileExtractionStarted;
            extr.FileExists += extr_FileExists;
            extr.ExtractionFinished += extr_ExtractionFinished;

                extr.ExtractArchive(directory);
            } catch (FileNotFoundException error) {
                if (varExtractionCancel) {
                    LogBoxTextAdd("[EXTRACTION WAS CANCELED]");
                } else {
                    MessageBox.Show(error.ToString(), "Error with extraction");
                    varExtractionFailed = true;
                }
            }
        }
        varExtractionFinished = true;
        return readOnlyVolumeFilenames;
    }

  private void extr_FileExists(object sender, FileOverwriteEventArgs e) {
        listViewLogFile.Invoke(new SetOverwriteDelegate((args) => LogBoxTextAdd(String.Format("Warning: \"{0}\" already exists; overwritten\r\n", args.FileName))), e);
    }
    private void extr_FileExtractionStarted(object sender, FileInfoEventArgs e) {
        listViewLogFile.Invoke(new SetInfoDelegate((args) => LogBoxTextAdd(String.Format("Extracting \"{0}\"", args.FileInfo.FileName))), e);
    }
    private void extr_Extracting(object sender, ProgressEventArgs e) {
        progressBarCurrentExtract.Invoke(new SetProgressDelegate((args) => progressBarCurrentExtract.Increment(args.PercentDelta)), e);
    }
    private void extr_ExtractionFinished(object sender, EventArgs e) {
        Invoke(new SetNoArgsDelegate(() => {
                                         //pb_ExtractWork.Style = ProgressBarStyle.Blocks;
                                         progressBarCurrentExtract.Value = 0;
                                         varExtractionFinished = true;
                                         //l_ExtractProgress.Text = "Finished";
                                     }));
    }

Of course you need to adjust things a bit, and use some of your own stuff. But for the sake of example I've added some additional methods.

Answer 2

You might skip the middle step and call the winrar.exe with the parameters straight instead of first instanciating cmd.exe

Also you might take a look at the 7-zip SDK