This one is easy. If you set a ListView column's width to -1, it automatically resizes to fit the data it contains. If you set the width to -2, it resizes to fit its data and column header.

This example displays buttons that let you set the ListView's column widths to 100 pixels, -1, or -2. The program uses the SetListViewColumnSizes method to set all of the column widths at once.

// Set the listView's column sizes to the same value.
private void SetListViewColumnSizes(ListView lvw, int width)
{
    foreach (ColumnHeader col in lvw.Columns)
    {
        col.Width = width;
    }
}