As you can see, event handling is hardly challenging. Listing 9-4 is a fun little program that jumps your Win Form around the screen depending on where your mouse pointer is and which mouse button you press within the client area of the form. If you have already written the method, select the method from the drop-down list next to the event that you want it to handle. MouseDown -= gcnew MouseEventHandler(this, Mouse_Clicked) Р В РІР‚СњР вЂ™Р’В®nter the name of the new method in the text box next to the event handler you are creating. If at a later time you no longer want this handler to handle the MouseDown event, all you need to do is remove the delegated method. MouseDown += gcnew MouseEventHandler(this, Mouse_Clicked) As you may recall from Chapter 4, C++/CLI uses multicast delegates therefore, you can chain as many handler methods as you need to complete the MouseDown event. Once you have the handler, all you need to do is delegate it onto the MouseDown event. Void Mouse_Clicked(System::Object^ sender, System::Windows::Forms::MouseEventArgs^ e) You donР В Р вЂ Р В РІР‚С™Р Р†РІР‚С›РЎС›t want any outside method calling this event by accident, as itР В Р вЂ Р В РІР‚С™Р Р†РІР‚С›РЎС›s only intended to be called within the event receiver class. Notice also that you make the handler private.

So, in the case of MouseDown, you need to create a method with the same signature as MouseEventHandler. The first step in creating an event receiver class is to create the event handler that will handle the event generated by the event source class.

Y: The vertical location of the mouse where it was clicked.

X: The horizontal location of the mouse where it was clicked.

A detent is one notch of the mouse wheel.

Delta: The number of detents the mouse wheel was rotated.

Clicks: The number of times the mouse was pressed and released.

Button: An enum class specifying which mouse button was pressed down.

Public delegate void MouseEventHandler(Object^ sender, MouseEventArgs^ e) Р В РІР‚СњР В РІР‚РЋor those of you who are curious, the class MouseEventArgs provides five properties that you can use to figure out information about the MouseDown event:

This event uses the MouseEventHandler delegate, which is defined in the

You need to define the event receiver class.Р В РІР‚СњР В РІР‚РЋor the following example, youР В Р вЂ Р В РІР‚С™Р Р†РІР‚С›РЎС›ll use the MouseDown event thatР В Р вЂ Р В РІР‚С™Р Р†РІР‚С›РЎС›s defined in the event source class System::Windows::Forms::Control: (You might want to revisit Chapter 4 if this means nothing to you.) Fortunately, many of the delegates and event source classes you need to worry about are already part of the. This requires a delegate, an event source class, and an event receiver class. NET FrameworkР В Р вЂ Р В РІР‚С™Р Р†РІР‚С›РЎС›s event model to handle all the events that take place within the form. This is exactly how the Win Form handles its userand system-generated events. Remember back in Chapter 4 when I discussed delegates and events and you thought to yourself, Р В Р вЂ Р В РІР‚С™Р РЋРЎв„ўThat would be a great way to handle an event-driven GUI application!Р В Р вЂ Р В РІР‚С™Р РЋРЎС™ You know what? You were right. For instance, this form has no control box and no minimize or maximize button, and in the bottom right there is a form-sizing grip and an up-arrow cursor.Р В РІР‚СњР вЂ™Р’В¬ H A P T E R 9 Р В Р вЂ Р Р†Р вЂљРІР‚СљР вЂ™Р’В B A S I C W I N D O W S F O R M S A P P L I C A T I O N S Notice that this form is quite a bit different from the default form generated by the previous example, Hello.exe. The running of CustomHello.exe results in the display in Figure 9-4. This->TopMost = true this->ResumeLayout(false) This->SizeGripStyle = System::Windows::Forms::SizeGripStyle::Show this->Text = L'Custom Form' System::Windows::Forms::FormBorderStyle::SizableToolWindow this->Name = L'Form1' This->ClientSize = System::Drawing::Size(692, 274) this->Cursor = System::Windows::Forms::Cursors::UpArrow this->FormBorderStyle = This->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font this->BackColor = System::Drawing::Color::Black

318 C H A P T E R 9 Р В Р вЂ Р Р†Р вЂљРІР‚СљР вЂ™Р’В B A S I C W I N D O W S F O R M S A P P L I C A T I O N S

Usercontrol autoscalemode inherit font