7.4 Drive, Directory and File List boxes
With just a few lines of code, you can add functionality to your programs by allowing users to
select files when needed in a program. This example application when completed, will let the
user see three different types of Windows images on the screen. The program uses five controls:
a drive list box, a directory list box, a file list box, an image control, and a label.
Activity 7.4 Picture Viewer
Steps:
1) Choose New Project from the File menu.
2) Create 5 controls: a drive list box, a directory list box, a file list box, an image control, and a
label.
3) In the properties window, set properties for the objects according to the following table:
Object
Property
Setting
Form
Caption
Picture Viewer
Drive list box
Name
drvList
Directory list box
Name
dirList
File list box
Pattern
*.BMP; *.WMF; *.ICO
Name
filList
BorderStyle
1 - fixed single
Name
imgOpen
Stretch
True
BorderStyle
1 - fixed single
Caption
(Empty)
Name
lblPathName
Image Control
Label
Your screen should resemble:
4) To make the drive, directory and file list boxes work in conjunction with each other, you need
to add the following code to the drvList_Change and dirList_Change event procedures:
Private Sub drvList_Change ()
dirList.Path = drvList.Drive ' Update directory path if drive changes
End Sub
Private Sub dirList_Change ()
filList.Path = dirList.Path ' Update file path if directory changes
End Sub
5) When a user double clicks on a file listed in the file list box, we want the filList_DblClick
event procedure to display the full path name of the selected file in the label control and display
the picture itself in the image control. This is how this is done:
Private Sub filList_DblClick ()
If Right (filList.Path, 1) <> "\" Then ' If current path doesn't end in a \
lblPathName.Caption = filList.Path & "\" & filList.FileName ' add it
Else ' If it already has a \
lblPathName.Caption = filList.Path & filList.FileName ' add name
End If
imgOpen.Picture = LoadPicture(lblPathName.Caption) ' load picture
End Sub