typedef struct tagTVINSERTSTRUCT {
    HTREEITEM hParent;
    HTREEITEM hInsertAfter;
#if (_WIN32_IE >= 0x0400)
    union
    {
        TVITEMEX itemex;
        TVITEM item;
    } DUMMYUNIONNAME;
#else
    TVITEM item;
#endif
} TVINSERTSTRUCT, FAR *LPTVINSERTSTRUCT;

TVITEM
 
typedef struct tagTVITEM{
    UINT      mask;
    HTREEITEM hItem;
    UINT      state;
    UINT      stateMask;
    LPTSTR    pszText;
    int       cchTextMax;
    int       iImage;
    int       iSelectedImage;
    int       cChildren;
    LPARAM    lParam;
} TVITEM, FAR *LPTVITEM;
 
Specifies or receives attributes of a tree view item. This structure is identical to the TV_ITEM structure, but it has been renamed to follow current naming conventions. New applications should use this structure.  
 
mask  
Array of flags that indicate which of the other structure members contain valid data. When this structure is used with the TVM_GETITEM message, the mask member indicates the item attributes to retrieve. This member can be one or more of the following values: TVIF_CHILDREN  The cChildren member is valid.  
TVIF_HANDLE  The hItem member is valid.  
TVIF_IMAGE  The iImage member is valid.  
TVIF_PARAM  The lParam member is valid.  
TVIF_SELECTEDIMAGE  The iSelectedImage member is valid.  
TVIF_STATE  The state and stateMask members are valid.  
TVIF_TEXT  The pszText and cchTextMax members are valid.  
 
hItem  
Identifies the item to which this structure refers.  
state  
A set of bit flags and image list indexes that indicate the item's state. When setting the state of an item, the stateMask member indicates the bits of this member that are valid. When retrieving the state of an item, this member returns the current state for the bits indicated in the stateMask member.  
Bits 0 through 7 of this member contain the item state flags. For a list of possible item state flags, see Tree View Control Item States.  
 
Bits 8 through 11 of this member specify the one-based overlay image index. The overlay image is superimposed over the item's icon image. If these bits are zero, the item has no overlay image. To isolate these bits, use the TVIS_OVERLAYMASK mask. To set the overlay image index in this member, you should use the INDEXTOOVERLAYMASK macro. The image list's overlay images are set with the ImageList_SetOverlayImage function.  
 
Bits 12 through 15 of this member specify the state image index. The state image is displayed next to an item's icon to indicate an application-defined state. If these bits are zero, the item has no state image. To isolate these bits, use the TVIS_STATEIMAGEMASK mask. To set the state image index, you should use the INDEXTOSTATEIMAGEMASK macro. The state image index specifies the index of the image in the state image list that should be drawn. The state image list is specified with the TVM_SETIMAGELIST message.  
 
stateMask  
Bits of the state member that are valid. If you are retrieving an item's state, set the bits of the stateMask member to indicate the bits to be returned in the state member. If you are setting an item's state, set the bits of the stateMask member to indicate the bits of the state member that you want to set. To set or retrieve an item's overlay image index, set the TVIS_OVERLAYMASK bits. To set or retrieve an item's state image index, set the TVIS_STATEIMAGEMASK bits.  
pszText  
Address of a null-terminated string that contains the item text if the structure specifies item attributes. If this member is the LPSTR_TEXTCALLBACK value, the parent window is responsible for storing the name. In this case, the tree view control sends the parent window a TVN_GETDISPINFO notification message when it needs the item text for displaying, sorting, or editing and a TVN_SETDISPINFO notification message when the item text changes.  
If the structure is receiving item attributes, this member is the address of the buffer that receives the item text.  
cchTextMax  
Size of the buffer pointed to by the pszText member, in characters. If this structure is being used to set item attributes, this member is ignored.  
iImage  
Index in the tree view control's image list of the icon image to use when the item is in the nonselected state.  
If this member is the I_IMAGECALLBACK value, the parent window is responsible for storing the index. In this case, the tree view control sends the parent a TVN_GETDISPINFO notification message to get the index when it needs to display the image.  
iSelectedImage  
Index in the tree view control's image list of the icon image to use when the item is in the selected state.  
If this member is the I_IMAGECALLBACK value, the parent window is responsible for storing the index. In this case, the tree view control sends the parent a TVN_GETDISPINFO notification message to get the index when it needs to display the image.  
cChildren  
Flag that indicates whether the item has associated child items. This member can be one of the following values: zero  The item has no child items.  
one  The item has one or more child items.  
I_CHILDRENCALLBACK  The parent window keeps track of whether the item has child items. In this case, when the tree view control needs to display the item, the control sends the parent a TVN_GETDISPINFO notification message to determine whether the item has child items.  
 If the tree view control has the TVS_HASBUTTONS style, it uses this member to determine whether to display the button indicating the presence of child items. You can use this member to force the control to display the button even though the item does not have any child items inserted. This allows you to display the button while minimizing the control's memory usage by inserting child items only when the item is visible or expanded.  
 
lParam  
A 32-bit value to associate with the item.