Create a TreeView with a checkbox

void __fastcall tform1::formcreate (tobject *sender)
{
SetWindowLong (Treeview1->handle,gwl_style,
GetWindowLong (Treeview1->handle,gwl_style) | Tvs_checkboxes);
}
Determine if a node is in a checked state
BOOL Getnodechecked (Ttreenode *anode)
{
Tvitem Tvitem;
Tvitem.mask = Tvif_handle | Tvif_state;
Tvitem.hitem = anode->itemid;
Tvitem.statemask = Tvis_stateimagemask;
Treeview_getitem (Anode->treeview->handle, &tvitem);
Return ((BOOL) (tvitem.state >> 12)-1);
}
Sets a node to be a checked state or unchecked state, determined by the parameter issettochecked
void setnodechecked (Ttreenode *anode,bool issettochecked)
{
Tvitem Tvitem;
Tvitem.mask = Tvif_handle | Tvif_state;
Tvitem.hitem = anode->itemid;
Tvitem.statemask = Tvis_stateimagemask;
Tvitem.state = Indextostateimagemask (issettochecked?2:1);
Treeview_setitem (Anode->treeview->handle, &tvitem);
}
void setchildchecked (Ttreenode *anode,bool yn)
{//Put all its descendants in the same place.
int count=anode->count;
Setnodechecked (Anode,yn);
if (count!=0)
for (int i=0;i<count;i++)//recursive
Setchildchecked (Anode->item[i],yn);
}
Ttreenode *clicknode; Nodes in the Save point
BOOL nodechecked; Node checked in the Save point
void __fastcall Tform1::treeview1mousemove (TObject *sender,
Tshiftstate Shift, int X, int Y)
{
Clicknode=treeview1->getnodeat (X,y);
if (clicknode!=null)//Save the checked value of the original node
Nodechecked=getnodechecked (Clicknode);
}
void __fastcall Tform1::treeview1mousedown (TObject *sender,
Tmousebutton Button, tshiftstate Shift, int X, int Y)
{
if (clicknode!=null)
if (getnodechecked (clicknode)!=nodechecked)
{//Put all its descendants in the same place.
nodechecked=!　nodechecked; Update it
Setchildchecked (clicknode,nodechecked);
}
}