- 1). Begin a new project by selecting the "Standard EXE" template after you open Visual Basic (VB). This opens a form window named "Form1." To demonstrate how validation works, add these controls to the form from the "ToolBox" on the left of the screen by double-clicking on each:
One "Label," represented by a large capital "A" icon.
One "TextBox," represented by an icon of a small square containing the letters "ab."
Two "CommandButtons," represented by a small blank rectangle icon. - 2). Click on and drag the controls you just added to separate them and align them as listed below. Each control added covers up the preceding ones, so the top one showing at this point is the last "CommandButton," named "Command2."
Move the "Command2" box to the right side of the form.
Move "Command1" above "Command2."
Move "Label1" to the left side of the form opposite "Command1."
Move "Text1" below "Label1." - 3). Click on "Label1" and change the "Caption" property in the "Properties" column on the right of the screen to read "Enter desired number between 1 and 1,000." Click on "Text1" and delete the default "Text" property. Change the "Caption" properties of "Command1" to "Go" and "Command2" to "Cancel." Change the "CausesValidation" property of "Command2" to "False." Note: Do not insert quotation marks when making these changes. Use the drag handles, the small squares around each control to widen them sufficiently to show the full contents.
- 4). Click "View" in the top level menu in VB and select "Code." Enter the following code on separate lines exactly as shown:
Private Sub Command1_Click()
MsgBox "Number is acceptable."
End Sub
Private Sub Command2_Click()
End
End Sub
Private Sub Text1_Validate(Cancel As Boolean)
If Not IsNumeric(Text1.Text) Then
Cancel = True
ElseIf CDbl(Text1.Text) < 1 Or CDbl(Text1.Text) > 1000 Then
Cancel = True
End If
If Cancel Then
MsgBox "The number entered must be between 1 and 1,000", vbExclamation
End If
End Sub - 5). Press "F5" to run the program. Enter any number on the form and click "OK." If the number falls between 1 and 1,000, you will see an acceptance message. Test by entering a number outside this range or text, which then gives an error message. Use this approach to validate other operations and perform desired operations upon the entered information.
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