Multi Document interfaceu
While designing an application with multiple forms init, we are setting the startup form under the program class, but as we don’t provide source code to client, When we develop a application, he doesn’t have chance to edit the class program and specify his startup Form. In that case we use Mdi Approach.
- In this approach we will be having only one form as a startup
form, so client doesn’t required to change it each time. Rest of the form in
application will be under the control of Main Form or start up Form.
- Here we will be having two parts:
- MDI Parent
- MDI Child
- The form which is going to be the startup form is MDI parent
and to make it as Mdi parent we need to set the IsMdiProperty of form as true.
Note –
An application can have only one MdiParent, all the other forms should be child
of parent, which comes and sits under parent;
Eg. Visual
Studio is an MdiParent which launches all the remaining form under it as
Childs.
- To launch a form as child of parent, create object of form
class we want to launch, set its MdiParent property with parent forms reference
and then call show method.
Layout: -
When we have more than one child form to be launched under parent the way how child form gets arranged in parent can be set with a layout, which has 4 options like:
i.
Cascade (D): - child
forms are arranged one on the top of the other
ii.
Tile Vertical: - child forms are arranged one beside the
other
iii.
Tile Horizontal: - child forms are arranged one blow the
other
iv.
ArrangeIcons: - all child icone are arranged with in
the parent.
Way to define a project with one MdiParent and its child:
-
- Take a new form on the project and sets its IsMdiContainer
property as true, so that it becomes as MdiParent and also set the windowstate
property as maximize, so that the form gets launched to the full size of the
screen.
- Place a menu strip control on a form and add two menus on it.
1. Forms,
2. Arrange
- Under Form menu add separator menu item for each form we want
to launch
E.g. Form1, Form2, Form3 etc.
- Under Arrange menu add the menu items – ArrangeIcons, Cascade,
vertical and Horizontal.
- Now write the following code:
Under Each Forms Menu Item:
Form1 f = new Form1();
f.MdiParent = this;
f.Show();
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Under arrange icons menu Strip:
this.LayoutMdi(MdiLayout.ArrangeIcons);
Under Cascade menu Strip:
this.LayoutMdi(MdiLayout.Casecade);
Under Vertical menu Strip:
this.LayoutMdi(MdiLayout.TileVertical);
Under Horizontal menu Strip:
this.LayoutMdi(MdiLayout.TileHorizontal);
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User Control
User Control These are controls that are created or developed by the
programmers. To consume under your application there are of two types –
- Creating a new control from existing controls.
- Inherited or Extended Controls.
- In the first case, we create new controls making use of
existing controls, so to design the control first we need to define a class
inheriting from the predefined class i.e. user control, which provide the
container required for designing.
** Image con not be displayed
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Syntax
public class StopClock : UserControl
{
// Design the control
// write behavior for the
control
}
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- In the second case without designing any control we only copy
the design of an existing control and add functionalities or behavior to the
control.
In this case, we define a class inheriting from the control
class and we have to add new behavior.
public class NumericTextBox : TextBox
{
// write the code for
accepting only numeric’s
}
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Note –
To create a control in the first process we need to add an item template of the
type user control, which provide a class inheriting from UserControl class.
Where as in the second case we need to add a item template of type class and
than
Inherit from the control class we want to extend.
Developing a Control
- People working on controls or classified into two Categories:
1. Component Developer
2. Component Consumer
- The person who develops a control is a component developer and
who consume the controls is a component consumer.
While developing component the
developer of the control should define all the behavior required for the
control and also defined any required properties, methods and event to the
control.
- Properties are defined to provide access for any
value of the control to consumers.
Eg: Text property for of TextBox, Checked property of CheckBox
etc.
- Method is defined so that the controls can
perform actions whenever required.
Eg: Clear(), Focus(), Methods of textbox
Close() method of Form etc.
- Events
While developing a control the developer of the control may not
know what action has to be performed at the specific time period.
Eg: the developer of the control is not
aware what should happen when button is clicked, what happen when button is
clicked will be decided by component consumer even if decided by consumer, it
is the responsibility of developer to execute the code written by consumer even
if these two persons never come together to work.
To resolve the above problem developer must first define an
event under their controls and then asked the consumer to write code under an
event procedure which should be bound with the event, So whenever the event
occur, event procedure gets executed.
Define an event:
[ < modifier >] event < delegate > <name>
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As we know that events takes the help of delegates to execute an
event procedure, so while defining an events we must also specified which
delegate will execute the event.
So first we need to define a delegate and then the event
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public event EventHandler click;
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- All delegates that are predefined in BCL are defined with two
parameters:
1. Object sender
2. EventArgs e
- That is the reason why all our event procedure are also taking
the same two parameters ( we are already aware that I/O parameter of delegate
should be same ass the I/O prams of method it has to call)
Note à While defining our own event to our
controls we can define delegates with or without parameters so that the event
procedure that are generated will also come with or without parameters
respectively.
Create a StopClock control:
à Open a new project of type windows
Forms Control library and name it as controls project.
à By default the project comes with a
class userControl1 that is inherited from user control
à Open the Solution explorer and rename
the file UserControl1.cs as StopClock.cs and design it as following.
Now goto the properties of Mask TextBox à select Mask property à click on the button beside it à select time à click ok à and also set text as “0000”
Place a timer control and set its interval property as 1000
Now write the following code in code view
** Code Can not be displayed..
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Now open the solution explorer à right click on the project à select built, which compile the
project and generated an assembly controlsProject.dll
Consuming the Controls è To consume the controls à goto our old project à open the toolbox à right click on it à and select add tab, which adds a new
tab à enter the name as csharp4
controls.
Now right click on the new tab and select choose items, which
opens a dialog box à click on the browser button and select controlsProject.dll
from its physical location.
c:\csharp4\controlsProject\Bin\Debug\controlsProject.dll
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After selecting the assembly à click on the OK button, which adds
StopClock control under the new tab we have added, which can be place on any
Form and consume it.
