Introduction

To assist you with visually getting a list of files inside a directory, the VCL provides an object named the file list box. To get it, in the Win 3.1 section of the Toolbox, click the TFileListBox control and click the form (or other container). In the VCL, this control is represented by a class of the same name.

1. Start Embarcadero RAD Studio
2. To create a new project, on the main menu, click File -> New -> VCL Forms Application - C++Builder
3. Change the Caption of the form to File Viewer
4. On the main menu, click File -> New -> Other
5. On the main menu, click File -> New -> Other
6. In the right list of the New Items dialog box, double-click Frame
7. Notice the name on the tab of the new frame
8. In the top section of the Code Edirtor, click Unit1.cpp
9. In the Standard section of the Tool Palette, click Frame and click the form
10. In the Select Frame to Insert dialog box, select the name of the new frame (it should be the last in the list) and click OK
11. In the top section of the Code Editor, click the UnitX.cpp of the last frame
12. In the Tool Palette, click Win 3.1
13. Click the TDriveComboBox button and click inside the frame
14. Press F9 to execute
15. Click the down-point button of the drive combo box
16. Close the form and return to your programming environment
17. In the Win 3.1 section of the Tool Palette, click the TDirectoryListBox control and click inside the frame
18. Adjust the design as follows:
     
    
19. On the Tool Palette, click Standard
20. Click the TLabel control and click inside the frame under the directory list box
     
    
21. In the frame, click the directory list box to select it
22. In the Object Inspector, click DirLabel and select Label1
23. Press F9 to execute
24. Change a drive in the combo box
25. Close the form and return to your programming environment
26. In the frame, click the drive combo box to select it
27. In the Object Inspector, click DirList and select DirectoryListBox1
28. Press F9 to execute
29. Change a drive in the combo box
30. Close the form and return to your programming environment

1. In the Tool Palette, cllick Win 3.1
2. In the Win 3.1 section, click the TFileListBox control and click inside the frame
3. Adjust the design as follows:
    
   

A file list box is used to show a list of files:

Normally, before uing it, a user should first select a directory, which is not possible in the file list box. To make this possible, you should add a directory list box and possibly a drive combo box:

After adding a directory list box, you should assign the file list box to it to allow the file list box to show the files of the currently selected directory. To support this, the TDirectoryListBox class is equipped with a property named FileList. This property is of type TFileListBox:

__property Filectrl::TFileListBox * FileList =
  		{read=FFileList,write=SetFileListBox};

To visually assign the file list box, access the Object Inspector for the directory list box. In the FileList field, select the name of the file list box.

1. In the frame, click the directory list box to select it
2. In the Object Inspector, click FileList and select FileListBox1
3. Press F9 to execute
4. Double-click a folder in the directory list box
5. Close the form and return to your programming environment

Before accessing a file, the user should first select the apppropriate drive in the drive combo box. The drive that is currently selected is identified by the Drive property of the TFileListBox class:

__property wchar_t Drive = {read=GetDrive,write=SetDrive};

This property behaves as its counterpart of the directory list box.

To use a directory list box, the user can click a directory to select it. When this is happens, the control fires an OnChange event. The file that is currently selected is represented by the FileName prpoperty:

__property System::UnicodeString FileName =
 		   {read=GetFilePath,write=ApplyFilePath};

To get the complete path and the name of the file that is currently selected, get the value of this property;

//---------------------------------------------------------------------------
void __fastcall TForm1::FileListBox1Change(TObject *Sender)
{
    ShowMessage(FileListBox1->FileName);
}
//---------------------------------------------------------------------------

By contrast, and because TFileListBox::FileName is a read-write property, to select a file, assign its complete path and name to this property. When you do this, make sure you provide a path that exists. Otherwise, you would receive an error.

When a file is selected, if you want, you can show its name in an edit box. To suppport this, the TFileListBox class is equipped with a property named EditFile:

__property Stdctrls::TEdit * FileEdit = {read=FFileEdit,write=SetFileEdit};

To visually use this property, add a TEdit control to your form. On the form, select the file list box. In the Object Inspector, select the name of the edit box in the EditFile field.

1. In the Tool Palette, click Standard
2. Click the TEdit control and click inside the frame
3. Adjust the design as follows:
    
   
4. In the Object Inspector, click the file list box to select it
5. In the Object Inspector, click FileEdit and select the Edit1 object
6. Press F9 to execute
7. Double-click a folder in the directory list box
8. Close the form and return to your programming environment