是一个风格TVS_CHECKBOXES
Version 4.70. Enables check boxes for items in a tree view control. A check box is displayed only if an image is associated with the item. When set to this style, the control effectively uses DrawFrameControl to create and set a state image list containing two images. State image 1 is the unchecked box and state image 2 is the checked box. Setting the state image to zero removes the check box altogether. For more information, see Working with state image indexes.
Version 5.80. Displays a check box even if no image is associated with the item.Note Once a tree view control is created with this style, the style cannot be removed. Instead, you must destroy the control and create a new one in its place. Destroying the tree view control does not destroy the check box state image list. You must destroy it explicitly. Get the handle to the state image list by sending the tree view control a TVM_GETIMAGELIST message. Then destroy the image list with ImageList_Destroy.If you want to use this style, you must set the TVS_CHECKBOXES style with SetWindowLong after you create the treeview control, and before you populate the tree. Otherwise, the checkboxes might appear unchecked, depending on timing issues.
Version 4.70. Enables check boxes for items in a tree view control. A check box is displayed only if an image is associated with the item. When set to this style, the control effectively uses DrawFrameControl to create and set a state image list containing two images. State image 1 is the unchecked box and state image 2 is the checked box. Setting the state image to zero removes the check box altogether. For more information, see Working with state image indexes.
Version 5.80. Displays a check box even if no image is associated with the item.Note Once a tree view control is created with this style, the style cannot be removed. Instead, you must destroy the control and create a new one in its place. Destroying the tree view control does not destroy the check box state image list. You must destroy it explicitly. Get the handle to the state image list by sending the tree view control a TVM_GETIMAGELIST message. Then destroy the image list with ImageList_Destroy.If you want to use this style, you must set the TVS_CHECKBOXES style with SetWindowLong after you create the treeview control, and before you populate the tree. Otherwise, the checkboxes might appear unchecked, depending on timing issues.
那是自己设的StateImage
GetCheck(HTREEITEM hItem);成员函数