VCL.MDIApp Sample

This sample shows the use of the customized tab preview in the Windows task bar for a Delphi/C++ application.

Location

You can find the MDIApp sample project at:

• Start | Programs | Embarcadero RAD Studio Berlin | Samples and then navigate to either:
  • Object Pascal\VCL\Taskbar\MDI
  • CPP\VCL\Taskbar\MDIApp
• Subversion Repository for Delphi: http://sourceforge.net/p/radstudiodemos/code/HEAD/tree/branches/RADStudio_Berlin/Object%20Pascal/VCL/Taskbar/MDI
• Subversion Repository for C++: http://sourceforge.net/p/radstudiodemos/code/HEAD/tree/branches/RADStudio_Berlin/CPP/VCL/Taskbar/MDIApp

Description

The application creates a main form that has the functionality to open images in a new child form. The application shows a thumbnail preview of each new image in the Windows task bar. You can close a tab by clicking the close button in the thumbnail preview in Windows task bar.

Note: Only .bmp images can be opened.

How to Use the Sample

1. Navigate to Start | Programs | Embarcadero RAD Studio Berlin | Samples and open:
   • Delphi: MDIApp.dproj
   • C++: CPPMDIApp.cbproj
2. Press F9 or choose Run > Run.

Files

This project has two source files:

File	Contains
MainMDIForm	The main form where new images are open and the child forms are created.
MDIChild	The child form where customized task bar preview functionality is done.

Classes

• TForm2, the form class, implements the main visual component of the application. It contains a TMainMenu component and a TActionList to open a image file in a child form.
• TFrMDIChild, the child form class, contains a TImage and the customized TTaskbar component. It implements the functionality to close the child form.

Implementation

• For the main form, in the Object Inspector set the FormStyle property to fsMDIForm. For the child form, in the Object Inspector set the FormStyle property to fsMDIChild.
• The menu item in the TMainMenu of the application is linked to the open file action in the TActionList, and a new child form is created for each opened image file.
• The TTaskbar component registers each new form as a new tab.
• For the TTaskbar component, in the Object Inspector set the CustomizedPreview property of the TabProperties to True. A preview thumbnail of each image is shown in the application Windows task bar.

Uses

• Vcl.Taskbar.TTaskbar
• Vcl.Taskbar.TTaskbar.TabProperties
• Vcl.ActnList
• Vcl.ImgList

See Also

• VCL Taskbars
• Building a VCL Forms MDI Application Without Using a Wizard
• MDI Applications
• VCL.OneFormApp_Sample
• VCL.VideoPlayer Sample