default keyword c#

C# > Keywords > default

This keyword is used in two ways.

• default label in switch statement
• generics: the default value
• null for reference type
• 0 for value type

Dependency Injection in C# with Autofac - real world example

C# > Patterns > Dependency Injection  > Autofac

Autofac is an addictive Inversion of Control container for .NET 4.5, Silverlight 5, Windows Store apps, and Windows Phone 8 apps

Source: http://autofac.org/

Dependency Injection in C# with Autofac - real world example

using Autofac;

using System;

using System.Linq;

using System.Collections.Generic;

using System.Windows.Forms;

namespace WindowsFormsApplication4

{

    public class Programmer

    {

        public string Name { get; set; }

        public IList<string> Skills { get; set; }

    }

    public class Project

    {

        public string Name { get; set; }

        readonly IList<Programmer> _programmers;

        readonly IDispatcher _dispatcher;

        public Project(IList<Programmer> programmers, IDispatcher dispatcher)

        {

            _programmers = programmers;

            _dispatcher = dispatcher;

        }

        public void FindProgrammers()

        {

            var programmers = _programmers.Where(e => e.Skills.Contains("VB"));

            foreach (var p in programmers)

                _dispatcher.Notify(p);

        }

    }

    public interface IDispatcher

    {

        void Notify(Programmer programmer);

    }

    public class Email : IDispatcher

    {

        private readonly string _message;

        public Email(string message)

        {

            _message = message;

        }

        public void Notify(Programmer programmer)

        {

            Console.WriteLine("Sent message {0} to {1}", _message,  programmer.Name);

        }

    }

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            List<Programmer> lst = new List<Programmer>();

            Programmer p = new Programmer();

            p.Name = "Dan";

            p.Skills = new List<string>();

            p.Skills.Add("VB");

            lst.Add(p);

            Email email = new Email("Notification email message");

            ContainerBuilder autofac = new ContainerBuilder();

            autofac.Register(o => new Project(o.Resolve<IList<Programmer>>(), o.Resolve<IDispatcher>()));

            autofac.RegisterType<Email>().As<IDispatcher>();

            autofac.RegisterInstance(lst).As<IList<Programmer>>();

            autofac.RegisterInstance(email).As<IDispatcher>();

           

            using (var container = autofac.Build())

            {

                container.Resolve<Project>().FindProgrammers();

            }

        }

    }

}

OrderBy Key Dictionary C#

C# > LINQ Query Expressions > OrderBy Key Dictionary

dictionary.OrderBy(key => key.Key);

Find max value of a column in a DataTable c#

C# > System.Data   > DataTable > Max Value

Find max value of a column in a DataTable C#.

var maxValue = DataTable1.AsEnumerable().Max(r => r.Field<double>("value"));

Appends text to a file C#

C# > Files > File Class > AppendText

Appends text to an existing file or create a new file if the specified file does not exist.

Example

using(System.IO.StreamWriter sw = System.IO.File.AppendText(@"c:\log.txt"))

{
      sw.WriteLine("logline");
}

Convert to double TimeSpan C#

C# > System > TimeSpan Structure

TimeSpan represents a time structure.

Examples

1. Convert to double

   

  TimeSpan ts = TimeSpan.FromMinutes(12.45);

  double time = ts.TotalMinutes;

Pow C# Example

C#  > System > Math class > Pow

Pow  number raise a  number to the specified power.

Example:

double pow = Math.Pow(2, 8); // 256

Scroll to selected index DataGridView

C# > DataGridView > FirstDisplayedScrollingRowIndex 

Setting this property raises scroll event to match selected index.

Example

dataGridView1.FirstDisplayedScrollingRowIndex = dataGridView1.Rows.Count - 1;

Read fast text file line by line C#

C# > Files > File Class > OpenText

Open text file for reading line by line.

Example

Read fast text file line by line C#

using (StreamReader sr = File.OpenText(@"c:\filename.txt"))

{

   while (!sr.EndOfStream)

   {

     sr.ReadLine();

    }
}

Print PictureBox Image C# Example Using PrintDocument

C# > Print  > PrintDocument

PrintDocument sends out to the printer.


Example

Print image

using System;

using System.Drawing;

using System.Windows.Forms;

namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            printPreviewDialog1.Document = printDocument1;

            printPreviewDialog1.ShowDialog();

        }

        private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)

        {

            e.Graphics.DrawImage(pictureBox1.Image, 100, 100, 700, 600);
        }
    }
}

C# unit test using Moq verify property has been set

C# > Unit test > Moq > Verify property has been set

SetupSet : Specifies a setup on the mocked type for a call to a property setter.

VerifySet : Verifies that a property has been set on the mock, regardless of its value.

Example

using System;

namespace UnitTestProject1

{

    public interface Interface1

    {

        int Id { get; set; }

    }

}

using Microsoft.VisualStudio.TestTools.UnitTesting;

using Moq;

namespace UnitTestProject1

{

    [TestClass]

    public class UnitTest1

    {

        [TestMethod]

        public void TestMethod1()

        {

            var mocker = new Mock<Interface1>();

            mocker.SetupSet(x => x.Id = 1);

            mocker.Object.Id = 1;

            mocker.VerifySet(x => x.Id);

        }

    }

}

Convert string to date C# example

C# > System Namespace > DateTime > Parse

Parse converts string to a date.

Example

string value = "5/15/2015";

var dte = DateTime.Parse(value, CultureInfo.InvariantCulture); // {5/15/2015 12:00:00 AM}

Reflection to find all classes implementing interface c#

C# > Reflection >  Find classes implementing interface

var iTtype = typeof(Interface);

var types = AppDomain.CurrentDomain.GetAssemblies()

           .SelectMany(a => a.GetTypes())

           .Where(t => iTtype.IsAssignableFrom(t));

Write, read XML to memory stream using XmlWriter and XmlReader C#

C# > XML > XmlWriter

XmlWriter  writes XML data to a file, stream,, text reader, or string.
It is fast, noncached and forward only.

Example
Write/read XML to memory stream.

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.IO;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Xml;

namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            MemoryStream stream = new MemoryStream();

            XmlWriter writer = XmlWriter.Create(stream);

            writer.WriteStartDocument();

            writer.WriteStartElement("Root");

            writer.WriteElementString("Child", "1");

            writer.WriteEndElement();

            writer.WriteEndDocument();

            writer.Flush();

            writer.Close();

            stream.Position = 0; // Resets the position to 0 so we can read.

            XmlReader reader = XmlReader.Create(stream);

            while (reader.Read())

            {

                //

            }

            reader.Close();

        }

    }

}