Private Sub Command1_Click( )
………………

OptionButton Controls in VB6

OptionButton controls are also known as radio buttons because of their shape. You always use OptionButton controls in a group of two or more because their purpose is to offer a number of mutually exclusive choices. Anytime you click on a button in the group, it switches to a selected state and all the other controls in the group become unselected.

Preliminary operations for an OptionButton control are similar to those already described for CheckBox controls. You set an OptionButton control’s Caption property to a meaningful string, and if you want you can change its Alignment property to make the control right aligned. If the control is the one in its group that’s in the selected state, you also set its Valueproperty to True. (The OptionButton’s Value property is a Boolean value because only two states are possible.) Value is the default property for this control.

At run time, you typically query the control’s Value property to learn which button in its group has been selected. Let’s say you have three OptionButton controls, named optWeekly, optMonthly, and optYearly. You can test which one has been selected by the user as follows:

If optWeekly.Value Then
‘ User prefers weekly frequency.
ElseIf optMonthly.Value Then
‘ User prefers monthly frequency.
ElseIf optYearly.Value Then
‘ User prefers yearly frequency.
End If

Strictly speaking, you can avoid the test for the last OptionButton control in its group because all choices are supposed to be mutually exclusive. But the approach I just showed you increases the code’s readability.

A group of OptionButton controls is often hosted in a Frame control. This is necessary when there are other groups of OptionButton controls on the form. As far as Visual Basic is concerned, all the OptionButton controls on a form’s surface belong to the same group of mutually exclusive selections, even if the controls are placed at the opposite corners of the window. The only way to tell Visual Basic which controls belong to which group is by gathering them inside a Frame control. Actually, you can group your controls within any control that can work as a container—PictureBox, for example—but Frame controls are often the most reasonable choice.

Example

Open a new Standard EXE project and the save the Form as Option.frm and save the project as Option.vbp.

Design the Form as per the following specifications table.

Object                           Property                              Settings

Label                                          Caption                                               Enter a Number

                                                      Name                                                   Label1

TextBox                                     Text                                                      (empty)

                                                      Name                                                    Text1

CommandButton                   Caption                                                &Close

                                                      Name                                                    Command1

OptionButton                           Caption                                                &Octal

                                                       Name                                                    optOct

OptionButton                           Caption                                                &Hexadecimal

                                                       Name                                                    optHex

OptionButton                           Caption                                                &Decimal 

                                                       Name                                                    optDec

The application responds to the following events

.The change event of the TextBox reads the value and stores it in a form-level numeric variable.

• The click event of optOct button returns curretval in octal.
• The click event of the optHex button curerntval in hexadecimal
• The click event of the optDec button returns the decimal equivalent of the value held currentval.

  The Val function is used to translate string to a number and can recognize Octal and Hexadecimal strings. The LTrim function trims the leading blanks in the text. The following code is entered in the click events of the OptionButton controls.

  Private Sub optOct_Click()
  Text1.Text = Oct(currentval)
  End Sub

  Private Sub optHex_Click()
  Text1.Text = Hex(currentval)
  End Sub

  Private Sub optDec_Click()
  Text1.Text = Format(currentval)
  End Sub

  The follwoing code is entered in the click event of teh Close button.

  Private Sub cmdClose_Click()
  Unlod Me
  End Sub