checkedListBox1.SelectedIndexChanged

for (int i = 0; i < checkedListBox1.Items.Count; i++)           
{                
  if (checkedListBox1.GetItemChecked(i))                
  {                    
      checkedListBox1.SetItemChecked(i, false);                
  }                
  else                
  {                    
    checkedListBox1.SetItemChecked(i, true);                
  }           
 } 
SelectedIndexChanged   
SelectedValueChanged事件