An application can add the names of files or subdirectories to a combo box by sending the CB_DIR message to it. The wParam parameter for the window procedure specifies the attributes of the files to add, and the lParam parameter points to the text string that defines the file specification.
Within a dialog box, an application can also use DlgDirListComboBox. If the specified filename includes a drive, path, or both, DlgDirListComboBox changes the current drive or directory and removes the drive and path from the filename string. To show the directory name, the function updates the specified static control, if any. It then resets the contents of the combo box, and sends the CB_DIR message to the combo box to add the specified filenames.
To remove the selected filename, directory name, or drive letter from a combo box that has been filled by using DlgDirListComboBox, an application can use the DlgDirSelectComboBoxEx function.
The DlgDirListComboBox and DlgDirSelectComboBoxEx functions and the CB_DIR message are similar to the DlgDirList and DlgDirSelectEx functions and the LB_DIR message used with list boxes.