Introduction to Text-Based Controls

Introduction to Labels

Description

A label is a control that serves as a guide to the user. It provides static text that the user cannot change but can read to get information on a form. The programmer can also use it to display simple information to the user. Most controls on the form are not explicit at first glance and the user may not know what they are used for. Therefore, you can assign a label to a control as a help to the user.

To add a label to a container, click the Label button from the Toolbox and click the object that would host it.

To programmatically create a label, declare a handle to Label, initialize it using its default constructor, and add it to the Controls property of the form. Here is an example:

Imports System.Drawing
Imports System.Windows.Forms

Module Exercise

    Public Class Starter
        Inherits Form

        Private lblMessage As Label

        Dim components As System.ComponentModel.Container

        Public Sub New()
            InitializeComponent()
        End Sub

        Public Sub InitializeComponent()

            lblMessage = New Label()
            Controls.Add(lblMessage)

        End Sub

    End Class

    Function Main() As Integer

        Dim frmStart As Starter = New Starter

        Application.Run(frmStart)

        Return 0
    End Function

End Module

1. Start Microsoft Visual Basic and create a Windows Application named ElementaryAddition1
2. From the Common Control section of the Toolbox, click Label and click the form
3. From the Common Control section of the Toolbox, click the Label again and click the form
4. From the Common Control section of the Toolbox, click the Label again and click the form

The most important characteristic of a label control is the text it displays. That text is also referred to as its caption and this is what the user would read. The text of a label is its Text property and is its default. To set a label’s caption, after adding the control to a container, click Text in the Properties window and type the desired value. As we mentioned when studying controls characteristics, at design time, the text you type in the Text field is considered “as is”. If you want to create a more elaborate and formatted string, you would have to do it programmatically. Here is an example:

Public Sub InitializeComponent()

            lblMessage = New Label()

            lblMessage.Text = Date.Today.ToLongDateString()

            Controls.Add(lblMessage)

End Sub

Here is an example of what this would produce:

When it comes to its caption, one of the most valuable characteristics of the text of a label is the variance of the font. When designing a caption. you can change the default font to make it more attractive.

1. On the form, click the first label
2. In the Properties window, click Text and type 00
3. Click (Name) and type lblOperand1
4. Click TextAlign and the arrow of its combo box to select Center
5. Click the + button of the Font field and change the characteristics as follows:
   Name: Tahoma
   Size:   48
   Bold:   True
6. On the form, click the second label and, in the Properties window, change its characteristics as follows:
   Text: +
   TextAlign: Center
   (Name): lblOPeration
   Font -> Name: Arial
   Font -> Size:   50
   Font -> Bold:   True
7. On the form, click the third label and, in the Properties window, change its characteristics as follows:
   Text: 00
   TextAlign: Center
   (Name): lblOperand2
   Font -> Name: Arial
   Font -> Size:   50
   Font -> Bold:   True
8. Save all

After adding a label to a form, by default, it receives a fixed size. If you type its caption and press Enter, the text you provided would be confined to the allocated dimensions of the control. If the text is too long, part of it may disappear. You can then resize the label to provide more area. Another solution is to automatically resize the label to accommodate the length of the string you typed. This is aspects is controlled by the Boolean AutoSize property. Its default value is False. If you set this property to True, at design time, a rectangular border appears around it. If you type a string in the Text field and press Enter, the control would be resized to show the whole string but using only the necessary space.

If you programmatically create a label, it assumes a default size. If you assign it a string that is too long for that default size, part of the string may appear on a subsequent line. If you want the whole string to appear on the same line, you can set the AutoSize to true. Here is an example:

Public Sub InitializeComponent()

            lblMessage = New Label()
            lblMessage.Text = Date.Today.ToLongDateString()

            lblMessage.AutoSize = True

            Controls.Add(lblMessage)

End Sub

Here is an example of what this would produce:

1. Click an unoccupied area of the form and press Ctrl + A to select all three labels
2. In the Properties window, double-click AutoSize to set the value to False
3. Save all

After typing the caption of a label whose AutoSize property is set to False, you can resize its allocated space to your liking. This is because a string occupies a rectangular area. Here is an example:

By default, the caption of a label is positioned starting on the middle-left side of its allocated rectangle. Alternatively, you can position it to one of the nine available positions. As we saw is Lesson 5, the position of the caption of a label is controlled by the TextAlign property which is based on the ContentAlignment enumerator:

It can have the following values:

TopLeft	TopCenter	TopRight
MiddleLeft	MiddleCenter	MiddleRight
BottomLeft	BottomCenter	BottomRight

Other fancy characteristics you can apply to a label include its font and color. For example, a label is primarily meant to display a string. To make it fancier, you can display a (small) picture next to it. To do this, at design time, use the Image field of the Properties window to select a picture. You can also specify the picture at run time by assigning an Image value to the Label.Image property. After adding a picture that would accompany the label, you can specify what position the picture would hold with regards to the label. To do this, select the desired position of the ImageAlign field in the Properties window.

Instead of using a picture from the Image property, you can create a list of images using an ImageList control and assign it to the label. In fact, the advantage of an ImageList is that, unlike the Image property, it allows you to use more than one picture.

After assigning an ImageList to the label control using the Properties window or code, you can use the ImageIndex to specify what picture to display next to the label.

A label provides another property called UseMnemonic. This property is valuable only when the label accompanies another control.

1. Complete the design of the form as follows:
    

   Control Text Name TextAlign Font Additional Properties Label 00 lblOperand1 Center Name: Tahoma Size:   48 Bold:   True ForeColor: Blue Label +   Center Name: Arial Size:   50 Bold:   True ForeColor: Maroon Label 00 lblOperand2 Center Name: Tahoma Size:   48 Bold:   True ForeColor: Blue Label =   Center Name: Arial Size:   50 Bold:   True ForeColor: Green Label 00 lblResult Center Name: Tahoma Size:   48 Bold:   True   Label New Operation lblNewOperation Center Name: Tahoma, Size: 28 Bold: True BorderStyle: Fixed3D ForeColor: White BackColor:Maroon  Label Quit lblQuit Center Name: Tahoma, Size: 28 Bold: True BorderStyle: FixedSingle

2. Double-click New Operation and implement its event as follows:
    

   Private Sub lblNewOperation_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) _ Handles lblNewOperation.Click Dim Operand1 As Integer Dim Operand2 As Integer Dim strAnswer As String Dim iAnswer As Integer Dim rnd As Random = New Random() Operand1 = rnd.Next(99) Operand2 = rnd.Next(99) Dim Result As Integer = Operand1 + Operand2 lblOperand1.Text = Operand1.ToString() lblOperand2.Text = Operand2.ToString() lblResult.Text = "0" Dim strPrompt As String = lblOperand1.Text & " + " & _ lblOperand2.Text & " =" strAnswer = InputBox(strPrompt, "Elementary Addition", "000", 100, 100) If IsNumeric(strAnswer) Then iAnswer = CInt(strAnswer) lblResult.Text = CStr(iAnswer) If iAnswer = Result Then MsgBox("WOW - Good Answer") Else MsgBox("PSSST - Wrong Answer") End If Else MsgBox("Invalid Numeric Value!") End If End Sub

3. In the Class Name combo box, select lblQuit
4. In the Method Name combo box, select Click and implement the event as follows:
    

   Private Sub lblQuit_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles lblQuit.Click End End Sub

5. Execute the application and test it
    
6. Click the Close button to close the form and return to your programming environment

In the past, to add an internet or email link to a form, there were many steps to follow. As the internet and email had become an integral part of the culture, it was also time to have an appropriate control adapted for this need. To address this issue, a control called LinkLabel is available from the .NET Framework.

As its name indicates, the LinkLabel control allows you to create a link. If you have done web development, you would know that a link can be made fancy by varying its colors. A link typically uses three different colors (actually, if you use cascading style sheet, you can add a fourth color as hover):

• Link: This is the general color used on a link that a user has not clicked before. The LinkLabel class defines this color through the LinkColor property.
• Active Link: When the user clicks a link, its target typically opens if everything is alright. This causes the link to change its color status. The color of an active link is represented in the LinkLabel class with the ActiveLinkColor property.
• Visited: When a user comes to a page or the document that provides a link, you can indicate whether the link was previously accessed or not. This is done by displaying a color other than the link color. The color of a previously visited link is represented in the LinkLabel class by the VisitedLinkColor property.

After creating a link, when the user accesses it, you can define some behavior the link would exhibit to the user, such as getting underlined or not underlined when the mouse passes over the link. The behaviors of a link can be controlled through the LinkBehavior property whose values are AlwaysUnderline, HoverUnderline, NeverUnderline, or the application would refer to Internet Options dialog box of Control Panel.

A link is typically meant to help the user switch to a different page or document when clicked. In some cases and at a particular time, you may not want the user to be able to click a link. In this case you can disable it. If you decide to disable a link, you can change its color using the DisabledLinkColor property. On the other hand, if the user is not able to access a link, that is, if a link is disabled, you can find out the color of that link from the DisabledLinkColor property.

Here is an example:

Imports System.Drawing
Imports System.Windows.Forms

Module Exercise

    Public Class Starter
        Inherits Form

        Friend WithEvents lnkConnector As LinkLabel

        Dim components As System.ComponentModel.Container

        Public Sub New()
            InitializeComponent()
        End Sub

        Public Sub InitializeComponent()

            lnkConnector = New LinkLabel()
            lnkConnector.Width = 150
            lnkConnector.Text = "Lessons and Topics"
            Controls.Add(lnkConnector)

        End Sub

        Private Sub ConnectorClicked(ByVal sender As Object, _
                                     ByVal e As LinkLabelLinkClickedEventArgs) _
                                     Handles lnkConnector.LinkClicked
            System.Diagnostics.Process.Start( _
                    "C:\Program Files\Internet Explorer\iexplore.exe", _
                    "http://www.functionx.com/vccli")
        End Sub
    End Class

    Function Main() As Integer

        Dim frmStart As Starter = New Starter

        Application.Run(frmStart)

        Return 0
    End Function

End Module

This would produce:

A text box is a Windows control used to get or display text to the user. At its most regular use, a text box serves as a placeholder to fill out and provide information. Such a use is common on employment applications, login dialog boxes, forms, etc. Like most other controls, the role of a text box is not obvious at first glance; that is why it should be accompanied by a label that defines its purpose.

From the user’s standpoint, a text box is named after the label closest to it. Such a label is usually positioned to the left or the top side of the text box. From the programmer’s point of view, a text box is a placeholder used for various things. For example, you can show or hide it as you see fit. You can also use it only to display text without allowing the user to change it.

To create a text box, from the Common Controls section of the Toolbox, you can click TextBox and click the form. The text box is based on the TextBox class. This means that you can use this class to dynamically create a text box and add it to your application. The text box control is based on the TextBox class whose immediate parent is TextBoxBase. Like every .NET Framework class, it has a constructor that can be used to dynamically create the control. Here is an example:

Imports System.Drawing
Imports System.Windows.Forms

Module Exercise

    Public Class Starter
        Inherits Form

        Private txtNotes As TextBox

        Dim components As System.ComponentModel.Container

        Public Sub New()
            InitializeComponent()
        End Sub

        Public Sub InitializeComponent()

            txtNotes = New TextBox
            txtNotes.Location = New Point(10, 10)
            Controls.Add(txtNotes)

        End Sub

    End Class

    Function Main() As Integer

        Dim frmStart As Starter = New Starter

        Application.Run(frmStart)

        Return 0
    End Function

End Module

The TextBoxBase class provides other methods derived from the control’s parent or from ancestor classes.

As a control primarily meant to display text, like a label, the text box shares many of the characteristics of a label: text alignment, font, color, etc.

The most important aspect of a text box is its text, whether it is displaying or requesting it. This is the Text property. When you add a text box control to a form or other container, by default, it is left empty. If you want the control to display some text when the form launches, type a string in the Text property field in the Properties window.

After creating a text box, it may be empty, the user can start typing in it to fill it with text. You can programmatically assign it a string to occupy it. Another way you can put or add text to the control is to paste the content of the clipboard, using text from another control. The syntax of the Paste() method is:

Public Sub Paste

At any time, to know the length of the text in the control, you can retrieve the value of the TextLength property, which is of type int.

The selection of text from a text box control can be performed either by you or by a user. To select part of the text, you can specify the starting point using the SelectionStart property, which is of type int. After the starting position, you can specify the number of characters to include in the selection. This is done using the SelectionLength property, which is of type int. The SelectionStart and the SelectionLength properties allow you to programmatically select text. The user, on the other hand, also knows how to select part of the text of the control. These operations can also be performed using the Select() method of the TextBox class. Its syntax is:

Public Sub Select(start As Integer, length As Integer)

Alternatively, the user may want to select the whole content of the control. To programmatically select the whole text of a text box control, call the SelectAll() method. Its syntax is:

Public Sub SelectAll

When  some text has been selected in the control, to get that text, you can retrieve the value of the SelectedText property, which is a handle to String.

After the text, in part or in whole, has been selected, you or the user can manipulate it. For example, you can copy the selection to the clipboard. This is done using the Copy() method. Its syntax is:

Public Sub Copy

To delete part of the text, the user can cut it. You can programmatically do this using the Cut() method. Its syntax is:

Public Sub Cut

To delete the whole contents of the text box, you can call the Clear() method. Its syntax is:

Public Sub Clear

Any operation performed on the text box can be undone using the Undo() method whose syntax is:

Public Sub Undo

To prevent an undo operation, call the ClearUndo() method. Its syntax is:

Public Sub ClearUndo

1. Create a new Window Application named ElementaryAddition2
2. Design the form as follows:
    

   Control Text Name TextAlign Font Additional Properties Label 00 lblOperand1 Center Name: Tahoma Size:   48 Bold:   True AutoSize: True ForeColor: Blue Label +   Center Name: Arial Size:   50 Bold:   True AutoSize: True ForeColor: Maroon Label 00 lblOperand2 Center Name: Tahoma Size:   48 Bold:   True AutoSize: True ForeColor: Blue Label =   Center Name: Arial Size:   50 Bold:   True AutoSize: True ForeColor: Green TextBox 000 txtResult Center Name: Tahoma Size:   48 Bold:   True   Label New Operation lblNewOperation Center Name: Tahoma, Size: 28 Bold: True AutoSize: True BorderStyle: Fixed3D ForeColor: White BackColor:Maroon  Label Check lblCheckAnswer Center Name: Tahoma, Size: 28 Bold: True AutoSize: True BorderStyle: Fixed3D ForeColor: White BackColor:Maroon  Label Quit lblQuit Center Name: Tahoma, Size: 28 Bold: True AutoSize: True BorderStyle: FixedSingle

3. Double-click the New Operation label and implement its event as follows:
    

   Private Sub lblNewOperation_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) _ Handles lblNewOperation.Click Dim Operand1 As Integer Dim Operand2 As Integer Dim rndNumber As Random = New Random() Operand1 = rndNumber.Next(99) Operand2 = rndNumber.Next(99) Dim Result As Integer = operand1 + operand2 lblOperand1.Text = CStr(Operand1) lblOperand2.Text = CStr(Operand2) txtResult.Text = "" txtResult.Focus() End Sub

4. In the Class Name combo box, select lblCheckAnswer
5. In the Method Name combo box, select Click and implement its event as follows:
    

   Private Sub lblCheckAnswer_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles lblCheckAnswer.Click Dim Operand1 As Integer Dim Operand2 As Integer Dim Result As Integer Try Operand1 = CInt(lblOperand1.Text) Catch MsgBox("Invalid Value") End Try Try Operand2 = CInt(lblOperand2.Text) Catch MsgBox("Invalid Value") End Try Try Result = CInt(txtResult.Text) If Result = (Operand1 + Operand2) Then MsgBox("WOW - Good Answer") Else MsgBox("PSSST - Wrong Answer") End If Catch MsgBox("Invalid Answer") End Try lblNewOperation_Click(sender, e) End Sub

6. In the Class Name combo box, select lblQuit
7. In the Method Name combo box, select Click and implement its event as follows:
    

   private void lblQuit_Click(object sender, EventArgs e) end End Sub

8. Execute the application and test it
9. Click the Close button to close the form and return to your programming environment

As mentioned already, a text box should be accompanied by a label that indicates what it is used for. To support this relationship, the Label control provides various properties. An accelerator character is a symbol of the label that provides easy access to its text box. On the label, such a character is underlined. An example would be First Name. The idea is that, if the user presses the Alt key in combination with the label’s underlined character, the text box it accompanies would receive focus.

To create an accelerator key, choose one of the label’s characters and precede it with an ampersand character when setting its caption. An example would be &First Name. If you want a label to display the accelerator character instead of a plain ampersand, set the label’s UseMnemonic property to true, which is already its default value. If you set it to true but need to display an ampersand, type two & characters where the ampersand would be shown.

The UseMnemonic property of a label is only used to indicate that the label would display an accelerator character and the & symbol typed on the label creates that accelerator character. To indicate which text box would receive focus when the accelerator character of the label is invoked, you must make sure you establish an appropriate tab sequence using the Tab Order menu item from the main menu or using the combination of TabStop/TabIndex properties. Typically, the label should have a Tab Order or TabIndex value that is just - 1 of that of the control it serves.

1. To start a new application, on the main menu, click File -> New -> Project (or File -> New Project)
2. In the Templates list, click Windows Application and set the name to PayrollProcessing1
3. Click OK
4. Design the form as follows:
    

   Control Name Text Other Properties GroupBox   Employee Identification   Label   &Employee Name:   TextBox txtEmployeeName     Label   Hourly &Salary:   TextBox txtHourlySalary     GroupBox   Time Values   Label   Monday   Label   Tuesday   Label   Wednesday   Label   Thursday   Label   Friday   Label   Saturday   Label   Sunday   Label   First Week:   TextBox txtMonday1 0.00 TextAlign: Right TextBox txtTuesday1 0.00 TextAlign: Right TextBox txtWednesday1 0.00 TextAlign: Right TextBox txtThursday1 0.00 TextAlign: Right TextBox txtFriday1 0.00 TextAlign: Right TextBox txtSaturday1 0.00 TextAlign: Right TextBox txtSunday1 0.00 TextAlign: Right Label   Second Week:   TextBox txtMonday2 0.00 TextAlign: Right TextBox txtTuesday2 0.00 TextAlign: Right TextBox txtWednesday2 0.00 TextAlign: Right TextBox txtThursday2 0.00 TextAlign: Right TextBox txtFriday2 0.00 TextAlign: Right TextBox txtSaturday2 0.00 TextAlign: Right TextBox txtSunday2 0.00 TextAlign: Right GroupBox   Payroll Processing   Label   Hours   Label   Amount   Button btnCalculate Calculate   Label   Regular   TextBox txtRegularTime 0.00 TextAlign: Right TextBox txtRegularAmount 0.00 TextAlign: Right Label   Net Pay:   TextBox txtNetPay 0.00 TextAlign: Right Label   Overtime   TextBox txtOvertime 0.00 TextAlign: Right TextBox txtOvertimeAmount 0.00 TextAlign: Right Button btnClose

5. Double-click the Close button and implement its Click event as follows:
    

   Private Sub btnClose_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) _ Handles btnClose.Click End End Sub

6. Save all

By default, a newly created text box is used to both display and receive text from the user. If you want the user to read text without being able to change it, set the ReadOnly Boolean property to True. Its default value is false.

1. On the form, click the text box at the intersection of Time and Regular
2. In the Properties window, double-click ReadOnly to change its value to True
3. Do the same for the following text boxes: txtRegularAmount, txtNetPay, txtOvertime, and txtOvertimeAmount

If a text box allows the user to enter text in it, the user can click the control and start typing. If a certain text box usually receives some known or common strings, you can assist the user with completing the entry. The TextBox class supports this with three properties.

If you want to assist the user with completing the string entered in a text box, first specify where the necessary strings will come from. You have two options. You can use the AutoCompleteSource property, that is based on the AutoCompleteSource enumeration. Its members are: None, RecentlyUsedList, FileSystem, FileSystemDirectories, HistoryList, ListItems, AllSystemSources, AllUrl, and CustomSource.

If you want to specify your own-created list of items, use the AutoCompleteCustomSource property. At design time, to create a list of strings, access the Properties window for the text box. In the Properties window, click the ellipsis button of the AutoCompleteCustomSource field to open the String Collection Editor. Enter the strings separated by a hard Return, and click OK.

After specifying the source of the list that will assist the user to complete the entry of the text box, set it AutoCompleteMode property. This property is based on the AutoCompleteMode enumeration that has four members. None is the default value.

1. On the form, click the txtEmployeeName text box
2. In the Properties window, click AutoCompleteCustomSource and click its ellipsis button
3. In the String Collection Editor, enter the following names:
   Micheline Hammond
   Paul Bertrand Yamaguchi
   Gertrude Monay
   Ernestine Ngaleu
   Andy Barang
   Christophe Yuen
   Jean Michel Kankan
4. Click OK
5. Click AutoCompleteSource, then click the arrow of its combo box and select CustomSource
6. Click AutoCompleteMode, then click the arrow of its combo box and select Accept
7. Right-click the form and click View Code
8. In the Class Name combo box, select btnCalculate
9. In the Method Name combo box, select Click and implement its event as follows:
    

   Private Sub btnCalculate_Click(ByVal sender As Object, _ ByVal e As System.EventArgs) _ Handles btnCalculate.Click Dim Monday1 As Double, Tuesday1 As Double Dim Wednesday1 As Double, Thursday1 As Double Dim Friday1 As Double, Saturday1 As Double, Sunday1 As Double Dim Monday2 As Double, Tuesday2 As Double Dim Wednesday2 As Double, Thursday2 As Double Dim Friday2 As Double, Saturday2 As Double Dim Sunday2 As Double, TotalHoursWeek1 As Double Dim TotalHoursWeek2 As Double Dim regHours1 As Double, regHours2 As Double Dim ovtHours1 As Double, ovtHours2 As Double Dim regAmount1 As Double, regAmount2 As Double Dim ovtAmount1 As Double, ovtAmount2 As Double Dim RegularHours As Double, OvertimeHours As Double Dim RegularAmount As Double, OvertimeAmount As Double Dim TotalEarnings As Double, HourlySalary As Double ' Retrieve the hourly salary Try hourlySalary = CDbl(txtHourlySalary.Text) Catch MsgBox("The value you typed for the salary is invalid" & _ vbCrLf & "Please try again") txtHourlySalary.Focus() End Try ' Retrieve the value of each day worked Try monday1 = CDbl(txtMonday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtMonday1.Focus() End Try Try tuesday1 = CDbl(txtTuesday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtTuesday1.Focus() End Try Try wednesday1 = CDbl(txtWednesday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtWednesday1.Focus() End Try Try thursday1 = CDbl(txtThursday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtThursday1.Focus() End Try Try friday1 = CDbl(txtFriday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtFriday1.Focus() End Try Try saturday1 = CDbl(txtSaturday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtSaturday1.Focus() End Try Try sunday1 = CDbl(txtSunday1.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtSunday1.Focus() End Try Try monday2 = CDbl(txtMonday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtMonday2.Focus() End Try Try tuesday2 = CDbl(txtTuesday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtTuesday2.Focus() End Try Try wednesday2 = CDbl(txtWednesday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtWednesday2.Focus() End Try Try thursday2 = CDbl(txtThursday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtThursday2.Focus() End Try Try friday2 = CDbl(txtFriday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtFriday2.Focus() End Try Try saturday2 = CDbl(txtSaturday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtSaturday2.Focus() End Try Try sunday2 = CDbl(txtSunday2.Text) Catch MsgBox("You typed an invalid value" & vbCrLf & _ "Please try again") txtSunday2.Focus() End Try ' Calculate the total number of hours for each week totalHoursWeek1 = monday1 + tuesday1 + wednesday1 + _ thursday1 + friday1 + saturday1 + sunday1 totalHoursWeek2 = monday2 + tuesday2 + wednesday2 + _ thursday2 + friday2 + saturday2 + sunday2 ' The overtime is paid time and half Dim ovtSalary As Double = HourlySalary * 1.5 ' If the employee worked under 40 hours, there is no overtime If TotalHoursWeek1 < 40 Then regHours1 = TotalHoursWeek1 regAmount1 = HourlySalary * regHours1 ovtHours1 = 0.0 ovtAmount1 = 0.0 ' If the employee worked over 40 hours, calculate the overtime ElseIf TotalHoursWeek1 >= 4 Then regHours1 = 40 regAmount1 = HourlySalary * 40 ovtHours1 = TotalHoursWeek1 - 40 ovtAmount1 = ovtHours1 * ovtSalary End If If TotalHoursWeek2 < 40 Then regHours2 = TotalHoursWeek2 regAmount2 = HourlySalary * regHours2 ovtHours2 = 0.0 ovtAmount2 = 0.0 ElseIf TotalHoursWeek2 >= 40 Then regHours2 = 40 regAmount2 = HourlySalary * 40 ovtHours2 = TotalHoursWeek2 - 40 ovtAmount2 = ovtHours2 * ovtSalary End If RegularHours = regHours1 + regHours2 OvertimeHours = ovtHours1 + ovtHours2 RegularAmount = regAmount1 + regAmount2 OvertimeAmount = ovtAmount1 + ovtAmount2 TotalEarnings = RegularAmount + OvertimeAmount txtRegularTime.Text = RegularHours.ToString("F") txtOvertime.Text = OvertimeHours.ToString("F") txtRegularAmount.Text = RegularAmount.ToString("F") txtOvertimeAmount.Text = OvertimeAmount.ToString("F") txtNetPay.Text = TotalEarnings.ToString("F") End Sub

10. Execute the application to see the result
     
    
11. Close the form and return to your programming environment

A text box can be configured to display only lowercase characters, only uppercase characters, or a mix. This characteristic is controlled by the CharacterCasing property, which is an enumerator that holds the same name. The default value of this property is Normal, which indicates that the control can use a mix of lowercase and uppercase characters. If you set this property to Lower, all existing characters, if any, in the control would be converted to lowercase and all future characters typed in the control would be automatically converted to lowercase. If you set this property to Upper, all existing characters, if any, in the control would be converted to uppercase and all future characters typed in the control would be automatically converted to uppercase.

Text typed in a text box appears with its corresponding characters unless you changed the effect of the CharacterCasing property from its default Normal value. This allows the user to see, and be able to read, the characters of the control. If you prefer to make the characters un-readable, you have two options.

The operating system uses a default character it uses to hide the contents of a text box. If you want to use that character, set the UseSystemPasswordChar property to true. If you prefer to specify your own character, you can use the PasswordChar property. Although this property is a char type of data, changing it actually accomplishes two things:

• If you type a character in its field in the Properties window, for example if you type *, any character typed in it would be un-readable
• Any character in the control would be replaced by the value of this property. You can use any alphabetic character or digit to represent the characters that would be typed but you must provide only one character.