C#

this.Show();
TreeView v = new TreeView();
this.Controls.Add(v);

v.Nodes.Add("hello");
	
TreeNodeCollection tnc = v.Nodes;
tnc[0] = new TreeNode("hello again");
MessageBox.Show(tnc.Count.ToString()); // outputs 1, despite 2 nodes showing up in the tree

private void MyControl_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
  switch (e.KeyCode)
  {
    case Keys.Insert:
      if (e.Modifiers == Keys.Shift)
      {
           // Do a shift Insert action.
          e.Handled = true;
      }
      return;
    case Keys.Enter:
      // Do an Enter Action.
      e.Handled = true;
      return;
    case Keys.Up:
      if (e.Modifiers == Keys.Shift)
      {
        if (CanMoveItemUp)
        {
	  MoveItemUp();
	  e.Handled = true;
        }
      }
      return;
    default:
      //all other keys
      return;
  }
}

public class GenericExmaple<T>
{
  public GenericExample(T parameter) {}
  // ...
}

GenericExample<string> ge = new GenericExample<string>(null);

public class GenericExample
{
  public GenericExample(object parameter)
  {
    if (parameter == null) throw new ArgumentNullException("parameter");
  }
}

if (parameter == null) throw new ArgumentNullException("parameter");
if (parameter.Equals(string.Empty))
  throw new ArgumentException("Error", "parameter");

Type t = typeof(T);
if (!t.IsValueType)
{
  // Use conditions from first example
}