/// <summary>
        /// Modify the space between groups
        /// </summary>
        /// <param name="olv"></param>
        /// <returns></returns>
        protected int SetGroupSpacing()
        {
            if (this.ListView.SpaceBetweenGroups <= 0)
            {
                return(0);
            }

            NativeMethods.LVGROUPMETRICS metrics = new NativeMethods.LVGROUPMETRICS();
            metrics.cbSize = ((uint)Marshal.SizeOf(typeof(NativeMethods.LVGROUPMETRICS)));
            metrics.mask   = (uint)GroupMetricsMask.LVGMF_BORDERSIZE;
            metrics.Bottom = (uint)this.ListView.SpaceBetweenGroups;
            return(NativeMethods.SetGroupMetrics(this.ListView, this.GroupId, metrics));
        }
        /// <summary>
        /// Modify the space between groups
        /// </summary>
        /// <param name="olv"></param>
        /// <returns></returns>
        protected int SetGroupSpacing() {
            if (this.ListView.SpaceBetweenGroups <= 0)
                return 0;

            NativeMethods.LVGROUPMETRICS metrics = new NativeMethods.LVGROUPMETRICS();
            metrics.cbSize = ((uint)Marshal.SizeOf(typeof(NativeMethods.LVGROUPMETRICS)));
            metrics.mask = (uint)GroupMetricsMask.LVGMF_BORDERSIZE;
            metrics.Bottom = (uint)this.ListView.SpaceBetweenGroups;
            return NativeMethods.SetGroupMetrics(this.ListView, this.GroupId, metrics);
        }