LB_DIR message

Adds names to the list displayed by a list box. The message adds the names of directories and files that match a specified string and set of file attributes. LB_DIR can also add mapped drive letters to the list box.



The attributes of the files or directories to be added to the list box. This parameter can be one or more of the following values.

Value Meaning
Includes archived files.
Includes subdirectories. Subdirectory names are enclosed in square brackets ([ ]).
All mapped drives are added to the list. Drives are listed in the form [-x-], where x is the drive letter.
Includes only files with the specified attributes. By default, read/write files are listed even if DDL_READWRITE is not specified.
Includes hidden files.
Includes read-only files.
Includes read/write files with no additional attributes. This is the default setting.
Includes system files.


A pointer to the null-terminated string that specifies an absolute path, relative path, or filename. An absolute path can begin with a drive letter (for example, d:) or a UNC name (for example, \\ machinename\ sharename).

If the string specifies a filename or directory that has the attributes specified by the wParam parameter, the filename or directory is added to the list. If the filename or directory name contains wildcard characters (? or *), all files or directories that match the wildcard expression and have the attributes specified by the wParam parameter are added to the list.

Return value

If the message succeeds, the return value is the zero-based index of the last name added to the list.

If an error occurs, the return value is LB_ERR. If there is insufficient space to store the new strings, the return value is LB_ERRSPACE.


The LB_INITSTORAGE message helps speed up the initialization of list boxes that have a large number of items (more than 100). It reserves the specified amount of memory so that subsequent LB_DIR messages take the shortest possible time. You can use estimates for the wParam and lParam parameters. If you overestimate, the extra memory is allocated; if you underestimate, the normal allocation is used for items that exceed the requested amount.

If wParam includes the DDL_DIRECTORY flag and lParam specifies all the subdirectories of a first-level directory, such as C:\TEMP\*, the list box will always include a ".." entry for the root directory. This is true even if the root directory has hidden or system attributes and the DDL_HIDDEN and DDL_SYSTEM flags are not specified. The root directory of an NTFS volume has hidden and system attributes.

The list displays long filenames, if any.

For an ANSI application, the system converts the text in a list box to Unicode using CP_ACP. This can cause problems. For example, accented Roman characters in a non-Unicode list box in Japanese Windows will come out garbled. To fix this, either compile the application as Unicode or use an owner-drawn list box.


Requirement Value
Minimum supported client
Windows Vista [desktop apps only]
Minimum supported server
Windows Server 2003 [desktop apps only]
Winuser.h (include Windows.h)

See also