using System;
using System.Windows.Forms;

namespace MyNamespace
{
    static class MyProgram
    {
        [STAThread]
        static void Main()
        {
            Application.Run(new MyForm());
        }
    }

    public class MyForm : Form
    {
        public MyForm()
        {
            this.Text = "My Program";
            this.Width = 800;
            this.Height = 600;
        }
    }
}

myForm.ControlBox = false;

myForm.MinimizeBox = false;
myForm.MaximizeBox = false;

private void InitMenus()
{
    MenuItem fileMenu = new MenuItem("File");
    fileMenu.MenuItems.Add("Open", new EventHandler(OpenFile));

    this.Menu = new MainMenu();
    this.Menu.MenuItems.Add(fileMenu);
}

private void OpenFile(object sender, EventArgs e)
{
}

ContextMenu contextMenu = new ContextMenu();
contextMenu.MenuItems.Add("Delete", OnDelete);

myControl.ContextMenu = contextMenu;

private void OnDelete(object sender, EventArgs e)
{
    Control myControl = (sender as MenuItem).GetContextMenu().SourceControl;
}

myForm.Icon = new Icon("icon.ico");

using System.IO;
using System.Reflection;

Assembly myAssembly = Assembly.GetAssembly(typeof(anyTypeInAssembly));
Stream iconStream = myAssembly.GetManifestResourceStream("MyFullNamespace.iconFilename.ico");
this.Icon = new Icon(iconStream);

using(Graphics graphics = this.CreateGraphics())
{
    SizeF size = graphics.MeasureString(text, font);
}
//versus
Size size = TextRenderer.MeasureText(text, font);

using System.Drawing;
...
Bitmap bitmap = new Bitmap(width, height);

protected override void OnPaint(PaintEventArgs paintEventArgs)
{
    paintEventArgs.Graphics.SmoothingMode = SmoothingMode.None; //allow pixelation
    paintEventArgs.Graphics.InterpolationMode = InterpolationMode.NearestNeighbor; //stop color smoothing
    paintEventArgs.Graphics.PixelOffsetMode = PixelOffsetMode.Half; //stops image from being shifted up-left by a half-pixel
    base.OnPaint(paintEventArgs);
}

Bitmap copy = (Bitmap)original.Clone();

Bitmap copy = new Bitmap(original);

private Bitmap SafeLoadImage(string fullFilename)
{
    byte[] imageBytes = File.ReadAllBytes(fullFilename);
    using(MemoryStream stream = new MemoryStream(imageBytes))
    {
        using(Image image = Image.FromStream(stream, false, true))
        {
            return new Bitmap(image);
        }
    }
}

private int CountLines(RichTextBox textBox)
{
    int lineCount = 1;
    while(textBox.GetFirstCharIndexFromLine(lineCount) > -1)
    {
        lineCount++;
    }
    return lineCount;
}

OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = "Image Files|*.BMP;*.PNG;*.JPG;*.JPEG";
openFileDialog.Title = "Select an Image File";

if(openFileDialog.ShowDialog() != System.Windows.Forms.DialogResult.OK)
{
    return;
}

//this will keep your dialog open
this.DialogResult = DialogResult.None;

//in owner
using(MyDialog form = new MyDialog())
{
    form.ShowDialog(this); //"this" sets the current form as the owner
}
//in dialog
public MyDialog()
{
    this.Shown += new EventHandler(Form_OnShown);
}
private void Form_OnShown(object sender, EventArgs e)
{
    Control owner = this.Owner;
    if(owner != null)
    {
        this.StartPosition = FormStartPosition.Manual;
        this.Location = new Point(owner.Location.X + (owner.Width - this.Width) / 2, owner.Location.Y + (owner.Height - this.Height) / 2);
    }
}

DialogResult result = MessageBox.Show("user message", "Title", MessageBoxButtons.OK, MessageBoxIcon.Error);

public class MyModal : Form
{
    public MyModal()
    {
        //create form
    }
    private void CloseForm()
    {
        this.DialogResult = DialogResult.OK;
        this.Close();
    }
}

public class MainForm : Form
{
    public MainForm()
    {
        //create form
    }
    public void DisplayModalForm()
    {
        using(MyModal myModal = new MyModal())
        {
            DialogResult result = myModal.ShowDialog();
        }
    }
}

using(MyModal form = new MyModal())
{
    form.StartPosition = FormStartPosition.Manual;
    form.Location = new Point(this.Location.X + 30, this.Location.Y + 30); //point on screen
    form.ShowDialog();
}

PictureBox pictureBox = new PictureBox();
pictureBox.Image = myBitmap; //load image from program memory
//or
pictureBox.ImageLocation = "myImage.png"; //load image from disk

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace PerpetualPaint
{
    public class PixelPictureBox : PictureBox
    {
        protected override void OnPaint(PaintEventArgs paintEventArgs)
        {
            if(ZoomedIn(paintEventArgs.Graphics))
            {
                paintEventArgs.Graphics.SmoothingMode = SmoothingMode.None; //allow pixelation
                paintEventArgs.Graphics.InterpolationMode = InterpolationMode.NearestNeighbor; //stop color smoothing
                paintEventArgs.Graphics.PixelOffsetMode = PixelOffsetMode.Half; //stops image from being shifted up-left by a half-pixel
            }
            base.OnPaint(paintEventArgs);
        }

        private bool ZoomedIn(Graphics graphics)
        {
            if(this.Image == null)
                return false;
            return (this.Image.Width < graphics.ClipBounds.Width || this.Image.Height < graphics.ClipBounds.Height);
        }
    }
}

public void OnClick(object sender, EventArgs e)
{
    Point screenPoint = new Point(MousePosition.X, MousePosition.Y);
}

public void OnClick(object sender, EventArgs e)
{
    Point screenPoint = new Point(MousePosition.X, MousePosition.Y);
    Point controlPoint = control.PointToClient(screenPoint);
}

using(Graphics graphics = Graphics.FromHwnd(IntPtr.Zero))
{
}