title: how to clean datagridview in C# - but stay with the originals columns header
body: <p>i have DatagridView in my C# program and i want to clean the grid</p>
  
  <p>(that the grid will be empty)</p>
  
  <p>i try <code>dataGridView1.DataSource = null;</code></p>
  
  <p>but it clean my header columns too</p>
  
  <p>how i can only clean the grid and leave the originals columns ?</p>
  
  <p>thank's in advance</p>