.NET Common Windows Forms Controls Part 1

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Author : Exforsys Inc. Published on: 26th Jun 2005 | Last Updated on: 6th Apr 2011

.NET Common Windows Forms Controls

In this tutorial we will learn about Common Windows Forms Controls in Visual Basic .NET 2005. IN this part 1 of this article, We will be learning the controls like Control Hierarchy, Label, LinkLabel, TextBox, RichTextBox, PictureBox, GroupBox, Panel, Button, CheckBox , RadioButton, ListBox, CheckedListBox and ComboBox.

Control Hierarchy

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The base class for all Windows controls is located in the System.Windows.Forms namespace. These controls are built into the .NET framework and form the basis for derived controls. These controls have a distinct hierarchy of their own. For example the hierarchy of the control rich text box is given below:

Object

MarshalByRefObject

Component

Control

TextBoxBase

RichTextBox

We shall take a quick look at some of the properties of the control:

Property	Description
AllowsDrop	Value that decides to accept data dropped in to it
Anchor	Gets/Sets the value of edges of the control to be anchored
BackColor	Gets/sets value of the color of the Background
CanFocus	Returns a value which specifies id the control can receive focus
DataBinding	Gets the data bindings for the control
Parent	Gets/Sets the controls parent container
Visible	Gets/Sets the value determines the visibility of the control

Some of the methods of the control are listed below:

Method	Description
BringToFront	Brings the control to the front of the stacking
Contains	Retrieves a value specifying if the control is a child of this control
Dispose	Releases the resources used by the control
GetType	Gets the type of the control
Hide	Hides the control
Invalidate	Invalidates a part of the control and sends a paint message to the control
DoDragDrop	Starts a drag and drop operation

Some of the events of the control are listed below:

BackgroundChanged	When the value of the backColor property is changed
Click	When mouse is clicked on the control
ControlAdded	When a new control is added
ControlRemoved	When a control is removed
SursorChanged	When the cursor property value ischanged
DragEnter	When an object is dragged into the control’s bounds
Enter	When the control is entered
GotFocus	When the control receives focus
Leave	When the location property value is changed
MouseWheel	When the mouse wheel moves whild the control has focus
VisibleChanged	When the Visible property value is changed

The above list is not exhaustive. However, a designer would find it profitable to get himself acquainted with the properties and methods of the different types of controls that he uses. Derived controls are customized controls that use the .NET framework controls as a base for building upon.

Label

The Label control is used in a number of applications to indicate the nature of the input required or the name of a control or just to convey a message to the user. The autosize property of this control is true by default, but can be dynamically fixed. Since this control cannot receive focus, it can also be used to create access keys for other controls.

Let us see a demo for this activity:

Draw the label first, and then draw the other control. Other wise draw the controls in any order and set the System.Windows.Forms.Control.TabIndex property of the label to one less than the other control.
Set the label's System.Windows.Forms.Label.UseMnemonic property to true.
Use an ampersand (&) in the label's System.Windows.Forms.Label.Text property to assign the access key for the label. For more information, see Creating Access Keys for Windows Forms Controls.
The following code will accomplish the task. Press F5 and see the demo in action.

Click here for the Sample Code

The output of the above codes is shown in the screenshot pasted below:

Link Labels

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This control is similar to the Label Control. In addition to all the properties, methods, and events of the Label control, the LinkLabel control has properties for hyperlinks and link colors. The LinkLabel.LinkArea property sets the area of the text that activates the link. The LinkLabel.LinkColor, LinkLabel.VisitedLinkColor, and LinkLabel.ActiveLinkColor properties set the colors of the link. The LinkLabel.LinkClicked event determines what happens when the link text is selected.

Link Labels are labels that support hyper links. Some of the important properties and events are given below:

Property/Event	Description
ActiveLinkColor	Gets/Sets the color for an active link
DisabledLinkColor	Gets/sets the color for an inactive link
LinkArea	Gets/Sets the range of that will be treated as link
LinkBehaviour	Gets/Sets the value that represents the behavior of a link
LinkColor	Gets/Sets the color of the link
LinkVisited	Gets/Sets the value specifying if a link should be displayed as though it had been visited
VisitedLinkColor	Gets/Sets the color used for the links that have been visited

The following code snippet demonstrates the usage of the link label.

Click here for the Sample Code

TextBox

The hierarchy of the control Text Box is given below:

Object

MarshalByRefObject

Component

Control

TextBoxBase

Text Box

This control is used mainly to collect user input of data and display text. The look and feel and the behavior can be controlled by manipulating the values of its properties, invoking some methods and also handling some of the events that this control is enabled to handle.

Some of the methods, properties and events of the text box are given below:

Property/Method/Event	Description
AutoSize	Sets/Gets value specifying if the control can resize itself automatically.
CanUndo	Return a value specifying if the user can undo the previous operation
Modified	Indicates if the text box control ha been modified by the user since the control was created or its contents were lost
Multiline	Sets/Gets value to determine if this is a multi-line text box control
SelectiedText	Sets/Get value for the currently selected text in the control box
SelectionLength	Sets/Gets value of number of characters selected
TextAlign	Gets/Sets how the test is aligned in the text box
WordWrap	Indicates if a multiline text box control automatically wraps the words
AppendText	Append textx to the current text in the text box
Clear	Clears all the text in the text box
Copy	Copies the selected text to the clipboard
Cut	Copies the selected text to the clip board and clears the text box
Select	Selects the text in the text box
Undo	Undoes the last edit operation in the text box
AutoSizeChanged	When the value of the autosizeproperty is changed
Click	When the text box is clicked
ReadonlyChanged	When the value of the readOnly property changed