protected unsafe override void WndProc(ref Message m)
{
switch (m.Msg)
{
case 8270:
NMHDR *ptr = (NMHDR *)((void *)m.LParam);
if (ptr->code == NM_CUSTOMDRAW)
{
NMTVCUSTOMDRAW nMTVCUSTOMDRAW = (NMTVCUSTOMDRAW)m.GetLParam(typeof(NMTVCUSTOMDRAW));
int dwDrawStage = nMTVCUSTOMDRAW.nmcd.dwDrawStage;
if (dwDrawStage == (CDDS_ITEM | CDDS_PREPAINT))
{
TreeNode treeNode = TreeNode.FromHandle(this, nMTVCUSTOMDRAW.nmcd.dwItemSpec);
if (treeNode != null)
{
using (Graphics graphics = Graphics.FromHdcInternal(nMTVCUSTOMDRAW.nmcd.hdc))
{
var bounds = treeNode.Bounds;
using (var brush = new SolidBrush(GetNodeRowBackgroundColor(treeNode)))
{
graphics.FillRectangle(brush, new Rectangle(0, bounds.Top, this.Width, bounds.Height));
}
}
}
}
}
break;
case WM_ERASEBKGND:
// in this handler erase only part of background that is not covered by nodes
TreeNode lastVisible = FindLastVisible(Nodes);
Rectangle r;
if (lastVisible != null)
{
r = new Rectangle(0, lastVisible.Bounds.Bottom, Width, Height);
}
else
{
r = new Rectangle(0, 0, Width, Height);
}
using (var g = CreateGraphics())
g.FillRectangle(Brushes.White, r);
m.Result = (IntPtr)1;
return; // skip default processing
case WM_HSCROLL:
Invalidate();
break;
}
base.WndProc(ref m);
}
protected void HideCheckBox(TV_ITEM tv_item)
{
if (tv_item.ItemHandle != IntPtr.Zero && tv_item.ItemHandle != hidingItemHandle)
{
// get TreeNode-object, that corresponds to TV_ITEM-object
TreeNode currentTN = TreeNode.FromHandle(this, tv_item.ItemHandle);
HiddenCheckBoxTreeNode hiddenCheckBoxTreeNode = currentTN as HiddenCheckBoxTreeNode;
// check if it's HiddenCheckBoxTreeNode and
// if its checkbox already has been hidden
if (hiddenCheckBoxTreeNode != null)
{
HandleRef treeHandleRef = new HandleRef(this, Handle);
// check if checkbox already has been hidden
TV_ITEM currentTvItem = new TV_ITEM();
currentTvItem.ItemHandle = tv_item.ItemHandle;
currentTvItem.StateMask = TVIS_STATEIMAGEMASK;
currentTvItem.State = 0;
IntPtr res = SendMessage(treeHandleRef, TVM_GETITEM, 0, ref currentTvItem);
bool needToHide = res.ToInt32() > 0 && currentTvItem.State != 0;
if (needToHide)
{
// specify attributes to update
TV_ITEM updatedTvItem = new TV_ITEM();
updatedTvItem.ItemHandle = tv_item.ItemHandle;
updatedTvItem.Mask = TVIF_STATE;
updatedTvItem.StateMask = TVIS_STATEIMAGEMASK;
updatedTvItem.State = 0;
hidingItemHandle = tv_item.ItemHandle;
try
{
// send TVM_SETITEM message
SendMessage(treeHandleRef, TVM_SETITEM, 0, ref updatedTvItem);
}
finally
{
hidingItemHandle = IntPtr.Zero;
}
}
}
}
}
