C++ Windows Forms L02 - Controls P1

Mohammad Shakermohammadshakergtr.wordpress.com

C++.NET Windows Forms Course@ZGTRShaker

C++.NET Windows Forms Course

L02 – Controls Part 1

Controls

• Form• Button• CheckBox• CheckedListBox• ComboBox• Label• ListBox• PictureBox

• ProgressBar• RadioButton• TextBox• Panel• TabControl• DataGridView• Timer

Windows Forms

Form’s Properties

Form’s Events

The Form is selected

• Applications :– Design Time VS runtime

• Controls :– Properties

• Width , color .. etc

– Events• MouseClick , MouseHover , DragDrop .. etc

Control Properties and Events

Your First Form: Form1

– Properties :• BackColor• AutoSize• Font• Location• Opacity• Size (width , Height )• Text

Form’s Properties

– Event :• Load (imp.)• Click• KeyUp \ down \ ….• MouseOver \ Down \ leave \ … • ResizeBegin \ End• TextChange• Validation• FormClosing• Form Closed

Form’s Events

Form at Design Time

With Form1 being selected

.ico extension

Forms Live TestingChanging Properties at runtime through Events

Button

– Properties :– Name , Text , Font , image , Location , Size , TabStop , TabIndex ,

Visible , BackColor

– Event :– MouseClick , MouseDown , MouseLeave , Resize , SizeChange ,

TextChanged , VisibleChanged , KeyUp , KeyDown , DragDrop

Button

Changing properties at runtime

• Considering we have the following design (at design time)

private: System::Void button1_Click(System::Object^

sender, System::EventArgs^ e)

{

button1 -> Text="I'm button1!!";

}

Control Property Valid value


• Adding the following button event



{

button1 -> Text="I'm button1!!";

}

Object (intsance)Reference button by

its name

Data Member Valid value


• Adding the following button event

After clicking the button




{

Form1 -> Text=" Hello World ”;

}

Member Valid value




{

Form1 -> Text=" Hello World ”;

}

Member Valid value


• Now , let’s change the “Form”’s Text property .



{

this -> Text="Hello World";

}

Member Value


Object at runtime (reference to Form1)Since we are inside

the Form1 class

After Clicking the Button



• Now , let’s change the “Form”’s Opacity property .



{

this -> Opacity=20; }

Class Member Valid value


• Now , let’s change the “Form”’s Opacity property .



{

this -> Opacity=0.2; }

Class Member Valid value

After Clicking the Button


Message Box



{

MessageBox::Show("Hello!!!");

}

MessageBox

Let the .NET write for you.Intellisense is ready to help you!

(Problem in 2010 and afterward)

21 Overload!

FormHide() vs Close()

What’s the difference between these two:

private: System::Void button1_Click(System::Object^ sender,

System::EventArgs^ e)

{

this->Hide();

}

private: System::Void button1_Click(System::Object^ sender,


{

this->Close();

}

Form Hide() vs Close()

private: System::Void Form1_Load(System::Object^


{

this->Hide();

}

Consider that we have only one form and we write the following code:

The form won’t be hidden on loading!

Form – Hide problem!



{

this->Hide();

}

What happens now when breaking the project and run it again?

It won’t compile! When hiding the form , the project is still processed!!!So we should terminate its process first from task manager

Form – Hide problem!

Opacity Problem , too!

The applications are hidden butnot closed. All the memoryallocated by each hiddenapplication is still there

Application class

Application class

• Hierarchy :– System.Windows.Forms

• Methods :– Run – Exit

• Informs all message pumps that they must terminate, and then closes all application windows after the messages have been processed.

Application::Exit();

Application class – Exit Method

private: System::Void Form1_Load(System::Object^ sender,


{


}

Application class – Exit Method

• What will happen now? The whole application (with all forms) will simply close and the resources will be freed.

• What’s the difference?


this->Close();

Exit() vs Close()

Managed vs Un-ManagedCODE

• Usually …– Managed : .NET– Un-Managed : C++

• gcnew

– Garbage collector

Managed VS Un-Managed

• Stack \ heap “Un-Managed heap” \ managed heap

• What’s the problem then?!!

int MyVar=10; \\ stack

int *Ptr=new int; \\ Un-Managed heap

int ^Ptr=gcnew int; \\ managed heap


• Let’s have the following, anything wrong?

int *Ptr=new int; \\ Un-Managed heap

Ptr=NULL;

It’s a leaking in memory!

int ^Ptr=gcnew int; \\ managed heap

Ptr=NULL;

Not a leak anymore!


private: System::Void button1_Click_1(System::Object^ sender,


{

Drawing::Size *S;

S->Height=200;

S->Width=300;

this->Size=*S;

}



{

Drawing::Size *S=gcnew Drawing::Size;

S->Height=200;

S->Width=300;

this->Size=*S;

}



{

Drawing::Size *S=new Drawing::Size;

S->Height=200;

S->Width=300;

this->Size=*S;

}

there’s no new \ unmanaged

gcnew with * \ unmanaged with managed

WORKS! \ unmanaged

Which one of these works?



{

Drawing::Size *S=new Size;

S->Height=200;

S->Width=300;

this->Size=*S;

} Un-Known Size identifier “3’laza :D”



{

Drawing::Size ^S=gcnew Drawing::Size;

S->Height=200;

S->Width=300;

this->Size=*S;

} Works! \ managed



{

Drawing::Size ^S=gcnew Drawing::Size;

S->Height=200;

S->Width=300;

this->Size=^S;

} Compiler error .. No such ^




{

Drawing::Size ^S;

S->Height=200;

S->Width=300;

this->S=^S;

}



{

Drawing::Size ^S=new Drawing::Size;

S->Height=200;

S->Width=300;

this->Size=^S;

}

Error .. ^

Should be gcnew , not new


private: System::Void button1_Click_1(System::Object^


{

this->Size=Drawing::Size(200,300);

}

Works!


References

msdn Awesome libraryC++ , C# , VB.NET , ASP.NET , XNA , XML ... etchttp://msdn.microsoft.com/en-us/library/default.aspx

http://msdn.microsoft.com/en-us/library/default.aspx

That’s it for today!

C++ Windows Forms L02 - Controls P1

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