C#

Details: Written by: Stanko Milosev; Category: C#; Published: 19 February 2022; Last Updated: 13 December 2023; Hits: 2192

core

One example of await and async from the book Pro C# 9 with .NET 5: Foundational Principles and Practices in Programming

using System;
using System.Threading;
using System.Threading.Tasks;

namespace AwaitAsyncExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Task.Run(async () =>
            {
                await MultipleAwaits();
            });

            Console.ReadKey();
        }

        static async Task MultipleAwaits()
        {
            Task task1 = Task.Run(() =>
            {
                Thread.Sleep(2_000);
                Console.WriteLine("Done with first task!");
            });
            Task task2 = Task.Run(() =>
            {
                Thread.Sleep(1_000);
                Console.WriteLine("Done with second task!");
            });
            Task task3 = Task.Run(() =>
            {
                Thread.Sleep(1_000);
                Console.WriteLine("Done with third task!");
            });
            await Task.WhenAll(task1, task2, task3);
        }
    }
}

Another example:

private static readonly Object ThisLock = new Object();

static void Main(string[] args)
{
  Task.Run(async () =>
  {
	await MultipleAwaits();
  });

  Console.ReadKey();
}

static async Task MultipleAwaits()
{
  Task task1 = Task.Run(() =>
  {
	lock (ThisLock)
	{
	  File.AppendAllText("test.txt", "test 1");
	}
  });
  Task task2 = Task.Run(() =>
  {
	lock (ThisLock)
	{
	  File.AppendAllText("test.txt", "test 2");
	}
  });
  Task task3 = Task.Run(() =>
  {
	lock (ThisLock)
	{
	  File.AppendAllText("test.txt", "test 3");
	}
  });
  await Task.WhenAll(task1, task2, task3);
}

Notice:

lock (ThisLock)
{
  File.AppendAllText("test.txt", "test 2");
}

Without lock exception "The process cannot access the file 'test.txt' because it is being used by another process." will be raised.

One more example in Windows forms:

namespace AsyncTest;

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        btnStart.Click += DoSomeWork;
    }

    async void DoSomeWork(object sender, EventArgs e)
    {
        label1.Text = "start";
        string text = await DoWait();
        label1.Text = text;
    }

    private Task<string> DoWait()
    {
        Task<string> task1 = Task.Run(() =>
        {
            Thread.Sleep(2_000);
            return Task.FromResult("did it");
        });

        return task1;
    }
}

Details: Written by: Stanko Milosev; Category: C#; Published: 21 November 2021; Last Updated: 30 November 2021; Hits: 3024

Here is one my example of in-memory DataTables master - detail relationship.
Create table with code like:

DataTable dtMaster = new DataTable("Master");

In this example I will add Columns without specifying type:

dtMaster.Columns.Add("Id");

Create new row:

DataRow drMaster = dtMaster.NewRow();
drMaster["Id"] = 1;

Add row to DataTable:

dtMaster.Rows.Add(drMaster);

Now details table:

DataTable dtDetail = new DataTable("Details");
dtDetail.Columns.Add("Id");
dtDetail.Columns.Add("FkDetailMasterId");

DataRow drDetail = dtDetail.NewRow();
drDetail["Id"] = 1;
drDetail["FkDetailMasterId"] = 1;
dtDetail.Rows.Add(drDetail);

Create DataSet and add relation:

DataSet ds = new DataSet();

ds.Tables.Add(dtMaster);
ds.Tables.Add(dtDetail);

DataRelation relMasterDetail = new DataRelation("MyRelation"
	, ds.Tables["Master"].Columns["Id"]
	, ds.Tables["Details"].Columns["FkDetailMasterId"]
);

ds.Relations.Add(relMasterDetail);

Example download from here.

Details: Written by: Stanko Milosev; Category: C#; Published: 17 October 2021; Last Updated: 07 November 2021; Hits: 2652

I have added a class library, and introduced one private method. Invoke looks like:

MethodInfoClass mic = new MethodInfoClass();

const BindingFlags bindingFlags = BindingFlags.InvokeMethod |
								  BindingFlags.Public |
								  BindingFlags.NonPublic |
								  BindingFlags.Static |
								  BindingFlags.Instance;

System.Reflection.MethodInfo privateTestMethod = typeof(MethodInfoClass).GetMethod("PrivateTestMethod", bindingFlags);

if (privateTestMethod is not null)
{
	string returnFromPrivateTestMethod = (string)privateTestMethod.Invoke(mic, null);
	Console.WriteLine($"privateTestMethod: {returnFromPrivateTestMethod}");
}

Example project download from here.

Details: Written by: Stanko Milosev; Category: C#; Published: 29 August 2021; Last Updated: 29 August 2021; Hits: 2455

As title said:

using System;
using System.Collections;
using System.Linq;

namespace IEnumarable
{
  class Program
  {
    static void Main(string[] args)
    {
      MyIEnumerable myIEnumerable = new MyIEnumerable();

      foreach (string test in myIEnumerable.Cast<string>().ToList())
      {
        Console.WriteLine(test);
      }
    }

    class MyIEnumerable : IEnumerable
    {
      private string _names = "stanko, milosev, elizabeta, lazarevic";

      public IEnumerator GetEnumerator()
      {
        string[] aryNames = _names.Split();

        foreach (string name in aryNames)
        {
          yield return name;
        }
      }
    }
  }
}

Await and async

Master - Detail example

Invoke private method with reflection

Example of IEnumerable casting

Subcategories

WPF

Beginning

Code snippets

NUnit

LINQ

Windows Forms