title: How to clear data from list view in c#
body: <p>I have a button "Show data". When click it, data will display in list view. But I want to clear it and then click "Show data" again to display new data. Because I don't want when I click "Show data" again It duplicated data. So I want to clear old data to show new data (no duplicated data). But its header no clear (still keep header). What is the source code?</p>
  
  <p>One more question. I want to show data from table in access to Datagridview in c# (eg. table in access contain: Name, Position, salary and Datagridview in c# has 3 column also: Name, Position and Salary by click on button "Show". What is the source code?</p>