CPropTree v1.0 - Property Tree Control

• Download demo project - 37 Kb
• Download demo source - 50 Kb

Introduction

The CPropTree class implements a tree control that is similar to the property view seen in Visual Studio .Net. The source project compiles to a DLL so you can easily incorporate it into your project. You can check my web page for more information on the control.

The control has two window areas:

• Tree Control
• Descriptive area

The tree control section functions just a like a normal tree control with an addition of a splitter bar separating the tree item properties. Tree item properties are inherited from the CPropTreeItem class. These items can be edit controls, static text, dropdown combo list, or any type of control you wish to create. Items on the root level of the tree control do not have editable properties. They are used as section headers.

Tree items can contain checkboxes. By default properties that are editable (non-readonly), are displayed in bold lettering. Read only or non-editable items are displayed in a normal font.

The descriptive area displays the selected item's text and any informational text. This section can be displayed or hidden by calling CPropTree::ShowInfoText().

Implementation

To use the control, create an instance of the class in your dialog or view class header. In the OnInitDialog() or OnCreate() initialize the control:

DWORD dwStyle;
CRect rc;

// PTS_NOTIFY - CPropTree will send notification messages to the parent window
dwStyle = WS_CHILD|WS_VISIBLE|PTS_NOTIFY;

// Init the control's size to cover the entire client area
GetClientRect(rc);

// Create CPropTree control
m_Tree.Create(dwStyle, rc, this, IDC_PROPERTYTREE);

To add items to the control, dynamically create objects inherited by the CPropTreeItem class and call the CPropTree::InsertItem() method.

CPropTreeItem* pItem1;

pItem1 = m_Tree.InsertItem(new CPropTreeItem());
pItem1->SetLabelText(_T("Properties"));
pItem1->SetInfoText(_T("This is a root level item"));

CPropTreeItem* pItem2;

pItem2 = m_Tree.InsertItem(new CPropTreeItemEdit(), pItem1);
pItem2->SetLabelText(_T("EditItem"));
pItem2->SetInfoText(_T("This is a child item of Properties, with an edit control"));

pItem2->SetItemValue((LPARAM)_T("This is some default text for the edit control"));

Advanced Features

Notification Messages

The control uses WM_NOTIFY notification messages to signal events. Add a ON_NOTIFY message handler to the parent window to process notifications. The control supports most of the common NM_ codes with addition of the following CPropTree specific WM_NOTIFY codes.

• PTN_INSERTITEM when an item is inserted
• PTN_DELETEITEM when an item is about to be deleted
• PTN_DELETEALLITEMS when a call is made to delete all items
• PTN_ITEMCHANGED when an item's property has been modified
• PTN_SELCHANGE when the current selection changed
• PTN_ITEMEXPANDING when an item is about to expand or close
• PTN_COLUMNCLICK when the mouse clicks on the splitter bar
• PTN_PROPCLICK when the mouse clicks on an item's property area
• PTN_CHECKCLICK when the mouse clicks on an item's checkbox

PTN_ notification messages returns the NMPROPTREE structure. You can use this structure along with the CPropTreeItem::SetCtrlID() method to determine the tree item that sent an event.

[...]
	//}}AFX_MSG_MAP
	ON_NOTIFY(PTN_ITEMCHANGED, IDC_PROPERTYTREE, OnItemChanged)
END_MESSAGE_MAP()


void CMyDialog::OnItemChanged(NMHDR* pNotifyStruct, LRESULT* plResult)
{
	LPNMPROPTREE pNMPropTree = (LPNMPROPTREE)pNotifyStruct;

	if (pNMPropTree->pItem)
	{
		// retrieve pItem's changed data
	}

	*plResult = 0;
}

Custom Property Items

The library already has some default derived CPropTreeItem classes ready to use. Such as an edit control CPropTreeItemEdit, color picker CPropTreeItemColor, dropdown combobox CPropTreeItemCombo and static text CPropTreeItemStatic. To create your own custom property items:

• Create your own class inherited by CPropTreeItem. This class usually will have multiple inheritance depending on what type of item you want to create.

  class CMyCustomEditPropItem : public CEdit, public CPropTreeItem
  {
  public:
  	CMyCustomEditPropItem();
  	virtual ~CMyCustomEditPropItem();
  
  	[...]
  };
  

  class CMyCustomComboBoxPropItem : public CComboBox, public CPropTreeItem
  {
  public:
  	CMyCustomComboBoxPropItem();
  	virtual ~CMyCustomComboBoxPropItem();
  
  	[...]
  };
  

• Override the CPropTreeItem virtual methods to implement your property item.
• Dynamically create an instance of your class and insert it into a CPropTree control.

The methods most often overriden from CPropTreeItem are:

• CPropTreeItem::OnActivate(). Called when the property area is clicked by the mouse or the enter key has been pressed on the selected item. The OnActivate() method is where you show the property item's window if it has one (such as an edit control or a popup menu).
• CPropTreeItem::OnCommit(). Called when data has been commited. In this method you would extract the changed data and hide the property's item's window. OnCommit() gets called when CommitChanges() is called. A derived CPropTreeItem class would call CommitChanges() during a loss of the input focus or if the "Enter" key is press as in a edit control.
• CPropTreeItem::DrawAttribute(). CPropTree calls DrawAttribute() when the property item needs to be displayed. Drawing is done directly on the display context of the PropTree control.