C#

public class MaskedTextBox : TextBox
{
	private string mask;
	public string Mask
	{
		get
		{
			return mask;
		}
		set
		{
			mask = value;
			this.Text = mask;
		}
	}

	protected override void OnKeyPress(KeyPressEventArgs e)
	{
		if (Mask != "")
		{
			e.Handled = true;
			string newText = this.Text;
			bool finished = false;
			for (int i = this.SelectionStart; i < mask.Length; i++)
			{
				switch (mask[i].ToString())
				{

						
					case "0" :
						if (Char.IsDigit(e.KeyChar) )
						{
							if(this.TextLength < mask.Length)
							{
								newText += e.KeyChar.ToString();
								finished = true;
								break;
							}
							else
							{
								newText=newText.Remove(i,this.SelectionLength);
								newText=newText.Insert(i,e.KeyChar.ToString());
							
								finished = true;
								break;
							}
						}
						else
						{
							// Invalid entry; exit and don't change the text.
							return;
						}
					default :
						// Insert the mask character.
						newText += mask[i];
						break;
				}
				if (finished)
				{ break; }
			}

			// Update the text.
			this.Text = newText;
			this.SelectionStart = this.Text.Length;
		}
	}

	protected override void OnKeyDown(KeyEventArgs e)
	{
		// Stop special characters.
		e.Handled = true;
	}
}

// Create a Matrix object
Matrix matrix = new Matrix();
// Rotate by 90 degrees
Point p=new Point(100,100);
matrix.RotateAt(90,p);
// Apply Matrix object to the Graphics object
g.Transform = matrix;
// Draw String
SizeF size=g.MeasureString("Vertical String",this.Font);
RectangleF rect=new RectangleF(0,0,size.Width,size.Height);
g.DrawString("Vertical String",this.Font,new SolidBrush(Color.Blue),rect);
// Dispose of object
g.Dispose();