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);
}
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);
}
}
