A TextBox control is an edit field or edit control, displays information entered
at design time, entered by the user, or assigned to the control using code at
run time.
Setting properties to a TextBox
* Text can be entered into the text box by assigning the necessary string
to the text property of the control
* If the user needs to display multiple lines of text in a TextBox, set the
MultiLine property to True
* To customize the scroll bar combination on a TextBox, set the ScrollBars
property.
* Scroll bars will always appear on the TextBox when it's MultiLine property
is set to True and its ScrollBars property is set to anything except None(0)
* If you set the MultilIne property to True, you can set the alignment using
the Alignment property. The test is left-justified by default. If the MultiLine
property is et to False, then setting the Alignment property has no effect.
* In order to work with the part of a text in a text box, the text can be selected
using three properties:
-
SelLength - Returns or sets the number of characters selected.
-
SelStart - Returns or sets the starting point of selected
text. When no text is selected, SelStart indicates the position of the inserted
point.
-
SelText - Returns or sets the string containing the currently
selected text. If no text is selected, SelText consists of a zero-length string.
The selected text can be copied to the Clipboard by using SelText:
Clipboard.SelText text, [format]
In the above syntax, text is the text that has to be placed into the Clipboard,
and format has three possible values.
1. VbCFLink - conversation information
2. VbCFRTF - Rich Text Format
3. VbCFText - Text
We get text from the clipboard using the GetText() function this way:
Clipboard.GetText ([format])
The following Figure summarizes the common TextBox control's properties and
methods.
| Property/ Method |
Description |
| |
|
| Enabled |
specifies whether user can interact with this control or not |
| Index |
Specifies the control array index |
| Locked |
If this control is set to True user can use it else if this control
is set to false the control cannot be used |
| MaxLength |
Specifies the maximum number of characters to be input. Default
value is set to 0 that means user can input any number of characters |
| MousePointer |
Using this we can set the shape of the mouse pointer when over
a TextBox |
| Multiline |
By setting this property to True user can have more than one line
in the TextBox |
| PasswordChar |
This is to specify mask character to be displayed in the TextBox |
| ScroolBars
|
This to set either the vertical scrollbars or horizontal scrollbars
to make appear in the TextBox. User can also set it to both vertical and horizontal.
This property is used with the Multiline property. |
| Text |
Specifies the text to be displayed in the TextBox at runtime |
| ToolTipIndex |
This is used to display what text is displayed or in the control |
| Visible |
By setting this user can make the Textbox control visible or invisible
at runtime |
|
Method |
|
| SetFocus |
Transfers focus to the TextBox |
|
Event procedures |
|
| Change |
Action happens when the TextBox changes |
| Click |
Action happens when the TextBox is clicked |
| GotFocus |
Action happens when the TextBox receives the active focus |
| LostFocus |
Action happens when the TextBox loses it focus |
| KeyDown |
Called when a key is pressed while the TextBox has the focus |
| KeyUp |
Called when a key is released while the TextBox has the focus |
Using a Label
Its a graphical control user can use to display uneditable text.
Properties of a Label Control
* We can write code that changes the caption property displayed by a Label
control in response to events at run time. We can also use a label to identify
a control, such as TextBox control, That doesn't have its own Caption property.
* The Autosize and WordWrap properties should be set if the user wants the
Label properly display variable-length lines varying numbers of lines.
Using a CommandButton
We can begin, interrupt or end a process using the CommandButton control
Properties of a CommandButton control
* To display text on a CommandButton control, set its caption property.
* An event can be activated by clicking on the CommandButton.
* To set the background colour of the CommandButton, select a colour in the
BackColor property.
* To set the text colour set the Forecolor property.
* Font for the CommandButton control can be selected using the Font property.
* To enable or disable the buttons set the Enabled property to True or False
* To make visible or invisible the buttons at run time, set the Visible property
to True or False.
* Tooltips can be added to a button by setting a text to the Tooltip property
of the CommandButton.
* A button click event is handled whenever a command button is clicked. To
add a click event handler, double click the button at design time, which adds
a subroutine like the one given below.
Private Sub Command1_Click( )
..................
End Sub
Using OptionButton Control
OptionButon provides a set of choices from which a user can select only one
button by
You can disable or enable the option button by setting the Enabled property
to True os False. You can use the Visible property to make the option button visible
to invisible.
The following example contains a Label, TextBox, CommandButton and three OptionButton
controls.
Example
Open a new Standard EXE project and the save the Form as Option.frm and save
the project as Option.vbp
| Object |
Property |
Settings |
| Label |
Caption
Name |
Amount
lblAmount |
| TextBox |
Text
Name |
(empty)
txtAmount |
| CommandButton |
Caption
Name |
Exit
cmdExit |
| OptionButton |
Caption
Name |
Without meal
optWithoutMeal |
| OptionButton |
Caption
Name |
With Meal
optWithMeal |
| Option Button |
Caption
Name |
Luxury Room
optLuxury |
| Form |
Caption
Name |
Select Room Type
frmType |
The application responds to the following events
The click event of the optWithoutMeal
displays the amount of 2500 in txtAmount.
The click event of the optWithMeal
displays the amount of 3500 in txtAmount.
The click event of the optLuxuty
displays the amount of 5000 in txtAmount.
The click event of the cmdExit
terminates the program
Following code is typed in the click events of the option buttons and the Exit
button.
The Application is run by pressing F5 or clicking on the Run icon in the tool
bar. By pressing the Exit button the program is terminated.
( Download the Source file)
