Validating textbox in vb net
The keys to the new validation features are the Validate event and the Causes Validation property.They work together as follows: When the input focus leaves a control, Visual Basic checks the Causes Validation property of the control that is about to receive the focus. Set Focus: Validate No Empty Fields = False End Function 'create as many form as you wish 'create label control array Label1 in each form ' write label caption that will finish with ':' for instance Address: ' create equal number of inputs for instance text boxes ' to avoid writing msg box when user missed some text box just put this to validate for instance on click event ' function will return which text box left without input with label's caption and will set focus there Set Frm For Check = Me ' will check if there are empty entries Index N = 1' this is for label array # 1, for 4 you put 4 and s.o. Item(Index N)) - 1), vb Information, "Empty record": Text Box Check.If this property is True, Visual Basic fires the Validate event in the control that's about to lose the focus, thus giving the programmer a chance to validate its contents and, if necessary, cancel the focus shift. Imagine that you have five controls on a form: a required field (a Text Box control, txt Required, that can't contain an empty string), a numeric field, txt Numeric, that expects a value in the range 1 through 1000, and three push buttons: OK, Cancel, and Help.
In other words, it ensures that one particular field is correct, not that all fields in the form contain valid data.Because the second field's Causes Validation property is True, Visual Basic fires a Validate event in the first Text Box control: Private Sub txt Required_Validate(Cancel As Boolean) ' Check that field is not empty. Text = "" Then Msg Box "Please enter something here", vb Exclamation Cancel = True End If End Sub If the Cancel parameter is set to True, Visual Basic cancels the user's action and takes the input focus back on the txt Required control: No other Got Focus and Lost Focus events are generated.On the other hand, if you typed something in the required field, the focus will now be on the second field (the numeric text box).The new Visual Basic 6 validation mechanism is simple and can be implemented with little effort.But it isn't the magic answer to all your validation needs.
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