Exemple #1
0
        internal void RunParallelExamples()
        {
            Stopwatch watch = new Stopwatch();

            // --------------------------------------------------------------------------------------------
            // Mit der Klasse Parallel können relativ einfach parallele Aufgaben erzeugt und abgearbeitet werden
            //

            // --------------------------------------------------------------------------------------------
            // Gibt 0 bis 9 in beliebiger Reihenfolge aus, da jeder Thread
            //   zu einem anderen Zeitpunkt ausgeführt werden könnte.
            Console.Write("[Parallel.For] Results = ");
            Parallel.For(0, 10, a => Console.Write("{0}, ", a));
            Console.WriteLine();



            // --------------------------------------------------------------------------------------------
            //Parallel.For(0, 50, a => a).



            // --------------------------------------------------------------------------------------------
            // Parallel.ForEach
            //   With Parallel.ForEach() an IEnumerable can be used to create tasks easily.
            watch.Restart();
            string text = StringData.CreateLongString();

            Console.Write("[Parallel.ForEach.Simple] Results = ");
            List <string> searchWords = new List <string> {
                "Gott", "Mann", "Weib"
            };

            Parallel.ForEach(searchWords, a => Console.Write("{0}({1}) ", a, text
                                                             .Split(new char[] { ' ', '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries)
                                                             .Count(b => string.Compare(a, b, true) == 0)));
            Console.WriteLine("in {0:0.000}s", watch.Elapsed.TotalSeconds);

            // --------------------------------------------------------------------------------------------
            // Parallel.ForEach Options
            //   Additionally one can use the ParallelOptions to setup some stuff, here the max amount of Tasks used.
            //   Others are using a different TaskFactory oder including a CancelationToken.
            watch.Restart();
            Console.Write("[Parallel.ForEach.Complex] Results = ");
            Parallel.ForEach(
                searchWords,
                new ParallelOptions {
                MaxDegreeOfParallelism = 2,
            },                                                       // Default for MaxDegreeOfParallelism is -1
                (w, s) =>
            {
                int count = text
                            .Split(new char[] { ' ', '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries)
                            .Count(b => string.Compare(w, b, true) == 0);
                Console.Write("{0}({1}) ", w, count);
            });
            Console.WriteLine("in {0:0.000}s", watch.Elapsed.TotalSeconds);


            // --------------------------------------------------------------------------------------------
            // Parallel.ForEach Break
            //   With Break the Parallel exceution can be stopped. If break was called the next task will not be started.
            watch.Restart();
            searchWords = new List <string> {
                "Gott", "Mann", "Weib", "Mensch", "Teufel", // "Hass", "Gnade", "Brot", "Wein", "Hund", "Tot"
            };
            Console.Write("[Parallel.ForEach.Break] Break results ");
            ParallelLoopResult result = Parallel.ForEach(
                searchWords,
                new ParallelOptions {
                MaxDegreeOfParallelism = 2,
            },
                (w, s) =>
            {
                int count = text
                            .Split(new char[] { ' ', '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries)
                            .Count(b => string.Compare(w, b, true) == 0);
                if (count < 20)
                {
                    s.Break();
                }
            });

            Console.Write("in {0:0.000}s ", watch.Elapsed.TotalSeconds);
            Console.WriteLine("while LowestBreakIteration = {0}, Completed = {1}", result.LowestBreakIteration, result.IsCompleted);
        }
Exemple #2
0
        public void RunAdoNetExamples()
        {
            // --------------------------------------------------------------------------------------------
            // - ADO.NET https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/
            //
            // - SqlConnection class https://docs.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqlconnection
            //

            // Creating the abstract base classes
            string       path       = Path.Combine(Environment.CurrentDirectory, "database.mdf");
            DbConnection connection = new System.Data.SqlClient.SqlConnection(
                string.Format(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename={0};Integrated Security=True", path));

            connection.Open();
            DbProviderFactory factory = DbProviderFactories.GetFactory(connection);

            // --------------------------------------------------------------------------------------------
            // ExecuteNonQuery
            using (DbCommand createCommand = factory.CreateCommand())
            {
                createCommand.Connection  = connection;
                createCommand.CommandText = "CREATE TABLE [Words] ([Id] INT NOT NULL PRIMARY KEY, [Word] NVARCHAR(50) NOT NULL, [Count] INT NOT NULL)";
                createCommand.ExecuteNonQuery();
            }

            // --------------------------------------------------------------------------------------------
            // ExecuteNonQuery with parameters
            using (DbCommand insertCommand = factory.CreateCommand())
            {
                DateTime current = DateTime.UtcNow;
                insertCommand.Connection  = connection;
                insertCommand.CommandText = "INSERT INTO [Words] ([Id], [Word], [Count]) VALUES (@id, @word, @count)";

                DbParameter idParameter = factory.CreateParameter();
                idParameter.DbType        = System.Data.DbType.Int32;
                idParameter.ParameterName = "@id";
                idParameter.Size          = 4;
                idParameter.Value         = 0;
                insertCommand.Parameters.Add(idParameter);

                DbParameter wordParameter = factory.CreateParameter();
                wordParameter.DbType        = System.Data.DbType.String;
                wordParameter.ParameterName = "@word";
                wordParameter.Size          = 100;
                wordParameter.Value         = 0;
                insertCommand.Parameters.Add(wordParameter);

                DbParameter countParameter = factory.CreateParameter();
                countParameter.DbType        = System.Data.DbType.Int32;
                countParameter.Size          = 4;
                countParameter.ParameterName = "@count";
                countParameter.Value         = 0;
                insertCommand.Parameters.Add(countParameter);

                insertCommand.Prepare();

                int      id    = 0;
                string   text  = StringData.CreateMediumString();
                string[] words = text.Split(new char[] { ' ', '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries);
                foreach (string word in words.Distinct())
                {
                    idParameter.Value    = id++;
                    wordParameter.Value  = word;
                    countParameter.Value = words.Count(a => a == word);
                    insertCommand.ExecuteNonQuery();
                }
                Console.WriteLine("[DbCommand.Parameters] Inserted {0} rows in {1:0.000}s", id + 1, (DateTime.UtcNow - current).TotalSeconds);
            }

            // --------------------------------------------------------------------------------------------
            // ExecuteScalar
            //   TODO
            using (DbCommand countCommand = factory.CreateCommand())
            {
                DateTime current = DateTime.UtcNow;
                countCommand.Connection  = connection;
                countCommand.CommandText = "SELECT COUNT(*) FROM [Words]";
                int count = (int)countCommand.ExecuteScalar();
                Console.WriteLine("[DbCommand.ExecuteScalar] Result Count = {0} in {1:0.000}s", count, (DateTime.UtcNow - current).TotalSeconds);
            }
        }