/// <summary>
/// Updates a <see cref="ListViewGroup"/> item's state within current instance as collapsible
/// </summary>
/// <param name="groupItemIndex">Group item index</param>
private void SetGroupCollapsible(int groupItemIndex)
{
LvGroup group = new LvGroup();
group.cbSize = Marshal.SizeOf(group);
group.state = LVGS_COLLAPSIBLE;
group.mask = LVGF_STATE;
group.iGroupId = groupItemIndex;
IntPtr ip = IntPtr.Zero;
try
{
ip = Marshal.AllocHGlobal(group.cbSize);
Marshal.StructureToPtr(group, ip, false);
SendMessage(Handle, LVM_SETGROUPINFO, groupItemIndex, ip);
}
finally
{
if (ip != IntPtr.Zero)
{
Marshal.FreeHGlobal(ip);
}
}
}
private static void SetGroupCollapsible(ListView listView, int state)
{
if (listView == null)
{
return;
}
foreach (ListViewGroup grp in listView.Groups)
{
object tmprtnval = propListVireGroupID?.GetValue(grp, null);
if (tmprtnval is int id)
{
LvGroup group = new LvGroup();
group.cbSize = Marshal.SizeOf(group);
group.state = (int)state; // LVGS_COLLAPSIBLE
group.mask = 4; // LVGF_STATE
group.iGroupId = id;
IntPtr ip = IntPtr.Zero;
try
{
ip = Marshal.AllocHGlobal(group.cbSize);
Marshal.StructureToPtr(group, ip, false);
SendMessage(listView.Handle, LVM_SETGROUPINFO, id, ip);
}
catch (Exception ex)
{
Trace.WriteLine(ex.Message + Environment.NewLine + ex.StackTrace);
}
finally
{
Marshal.FreeHGlobal(ip);
}
}
}
}
private static void ToggleGroupCollapseState(IntPtr handle, int id)
{
int i = id;
LvGroup group = new LvGroup();
group.cbSize = Marshal.SizeOf(group);
group.mask = 4; // LVGF_STATE
group.iGroupId = i;
IntPtr ip = IntPtr.Zero;
try
{
ip = Marshal.AllocHGlobal(group.cbSize);
Marshal.StructureToPtr(group, ip, false);
var rst = SendMessage(handle, LVM_GETGROUPSTATE, i, Collapsed); // #define LVM_GETGROUPINFO (LVM_FIRST + 149)
if (rst == Collapsed)
{
group.state = Collapsible;
}
else
{
group.state = Collapsible + Collapsed;
}
Marshal.StructureToPtr(group, ip, false);
SendMessage(handle, LVM_SETGROUPINFO, i, ip); // #define LVM_SETGROUPINFO (LVM_FIRST + 147)
}
catch (Exception ex)
{
Trace.WriteLine(ex.Message + Environment.NewLine + ex.StackTrace);
}
finally
{
Marshal.FreeHGlobal(ip);
}
}
