private static void setGrpState(ListViewGroup lstvwgrp, ListViewGroupState state)
{
if (Environment.OSVersion.Version.Major < 6) //Only Vista and forward
// allows collapse of ListViewGroups
{
return;
}
if (lstvwgrp == null || lstvwgrp.ListView == null)
{
return;
}
if (lstvwgrp.ListView.InvokeRequired)
{
lstvwgrp.ListView.Invoke(new CallBackSetGroupState(setGrpState),
lstvwgrp, state);
}
else
{
int? GrpId = GetGroupID(lstvwgrp);
int gIndex = lstvwgrp.ListView.Groups.IndexOf(lstvwgrp);
LVGROUP group = new LVGROUP();
group.CbSize = Marshal.SizeOf(group);
group.State = state;
group.Mask = ListViewGroupMask.State;
if (GrpId != null)
{
group.IGroupId = GrpId.Value;
SendMessage(lstvwgrp.ListView.Handle,
LVM_SETGROUPINFO, GrpId.Value, group);
SendMessage(lstvwgrp.ListView.Handle,
LVM_SETGROUPINFO, GrpId.Value, group);
}
else
{
group.IGroupId = gIndex;
SendMessage(lstvwgrp.ListView.Handle, LVM_SETGROUPINFO, gIndex, group);
SendMessage(lstvwgrp.ListView.Handle, LVM_SETGROUPINFO, gIndex, group);
}
}
}
private static extern int SendMessage
(IntPtr hWnd, int Msg, int wParam, LVGROUP lParam);