C++ Windows Forms L02 - Controls P1

C++.NET
Windows Forms Course
L02 – Controls Part 1

Mohammad Shaker
mohammadshakergtr.wordpress.com
C++.NET Windows Forms Course
@ZGTRShaker

Controls
•
•
•
•
•
•
•
•

Form
Button
CheckBox
CheckedListBox
ComboBox
Label
ListBox
PictureBox

•
•
•
•
•
•
•

ProgressBar
RadioButton
TextBox
Panel
TabControl
DataGridView
Timer

Form’s Properties
Form’s Events

The Form is selected

Control Properties and Events
• Applications :
– Design Time VS runtime

• Controls :
– Properties
• Width , color .. etc

– Events
• MouseClick , MouseHover , DragDrop .. etc

Form’s Properties
– Properties :
•
•
•
•
•
•
•

BackColor
AutoSize
Font
Location
Opacity
Size (width , Height )
Text

Form’s Events
– Event :
•
•
•
•
•
•
•
•
•

Load
Click
KeyUp down ….
MouseOver Down leave …
ResizeBegin End
TextChange
Validation
FormClosing
Form Closed

(imp.)

Form at Design Time
With Form1 being selected

Forms Live Testing
Changing 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

Changing properties at runtime
• Considering we have the following design (at design time)

• Adding the following button event

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


After clicking the button


{
Form1 -> Text=" Hello World ”;
}

Member

Valid value

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

{
Form1 -> Text=" Hello World ”;
}

Member

Valid value


{
this -> Text="Hello World";
}

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

Member

Value


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

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

Let the .NET write for you.
Intellisense is ready to help you!
(Problem in 2010 and afterward)

Form Hide() vs Close()
What’s the difference between these two:

System::EventArgs^ e)
{
this->Hide();
}

sender,

{
this->Close();
}

sender,

Form – Hide problem!
Consider that we have only one form and we write the
following code:
private: System::Void Form1_Load(System::Object^
{
this->Hide();
}

The form won’t be hidden on loading!

Form – Hide problem!
What happens now when breaking the project and run it again?

{
this->Hide();
}

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

The applications are hidden but
not closed. All the memory
allocated by each hidden
application is still there

Application class
• Hierarchy :
– System.Windows.Forms

• Methods :
– Run
– Exit

Application class – Exit Method
• 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
• What will happen now?
The whole application (with all forms) will simply close and
the resources will be freed.
private: System::Void Form1_Load(System::Object^
{
}

sender,

Exit() vs Close()
• What’s the difference?
this->Close();

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

• gcnew
– Garbage collector

• Stack heap “Un-Managed heap” managed heap
int MyVar=10;

stack

int *Ptr=new int;

Un-Managed heap

int ^Ptr=gcnew int; managed heap

• What’s the problem then?!!

• Let’s have the following, anything wrong?

int *Ptr=new int;
Ptr=NULL;

Un-Managed heap

It’s a leaking in memory!

Ptr=NULL;
Not a leak anymore!

• Let’s have the following, anything wrong?
int *Ptr=new int;
Ptr=NULL;

Un-Managed heap

It’s a leaking in memory!

Ptr=NULL;
Not a leak anymore!

Which one of these works?
private: System::Void button1_Click_1(System::Object^ sender,
{
Drawing::Size *S;
S->Height=200;
S->Width=300;
this->Size=*S;
}
there’s no new unmanaged
{
Drawing::Size *S=gcnew Drawing::Size;
S->Height=200;
S->Width=300;
this->Size=*S;
gcnew with * unmanaged with managed
}
{
Drawing::Size *S=new Drawing::Size;
S->Height=200;
S->Width=300;
this->Size=*S;
WORKS! unmanaged
}

{
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

private: System::Void button1_Click_1(System::Object^
{
Drawing::Size ^S;
S->Height=200;
S->Width=300;
this->S=^S;
}
Error .. ^

sender,

{
Drawing::Size ^S=new Drawing::Size;
S->Height=200;
S->Width=300;
this->Size=^S;
}
Should be gcnew , not new


private: System::Void button1_Click_1(System::Object^
{
this->Size=Drawing::Size(200,300);
}
Works!

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

C++ Windows Forms L02 - Controls P1

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