C#

for (int i = 0; i < dataGridView1.Rows.Count; i++)
              {
                  dataGridView1.BackgroundColor = Color.Red;
                  if (i % 2 == 0)
                  {
                      dataGridView1.BackgroundColor = Color.Blue;
                  }
              }

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
     {
         for (int i = 0; i < dataGridView1.Columns.Count; i++)
         {
             e.CellStyle.BackColor = Color.Red;
             if (i % 2 == 0)
             {
                 e.CellStyle.BackColor = Color.Blue;
             }
         }
     }

public void Dispose()
{
  if (img != null) img.Dispose();
}

using (var x = new MyThing()) // MyThing is IDisposable
{
   ... code block ...
}

// is equivalent to

var x = new MyThing();
try
{
   ... code block ...
}
finally
{
   if (x != null) x.Dispose();
}

public class MyBaseClass
{
  // Some stuff in here.
  public virtual void Dispose()
  {}
}
public class MyDisposableBaseClass : MyBaseClass, IDisposable
{
  // No need to implement the Dispose method here because this
  // class derives from a class that already has a Dispose, method
  // even though that class doesn't implement IDisposable.
}
// some code, which then gets called as:
using (MyBaseClass myClass = new MyDisposableBaseClass())
{
  // There's a problem, and this won't compile because MyBaseClass does not
  // implement IDisposable.
}
// Change the code to
using (MyDisposableBaseClass myClass = new MyDisposableBaseClass())
{
  // The code gets disposed automatically.
}