How Do I check if a Masked Text Box is Null or Empty ? (WinForms. VB.Net)

Question

Hi Good People

How do I check if the Masked Textbox is Null or Empty, As the Masked Textbox has Symbols if no Numbers are typed into the Masked Textbox. I have tried to write code for a empty Masked Textbox to no avail.

The Symbols are setup as:

Number, Number, Space, Symbol (-) Space, Number, Number, Space, Symbol (-) Space, Number, Number

Picture 1 denotes an empty Masked Textbox.

Picture 2 denotes a Filled Masked Textbox.

Kind Regards

Gary

Answer 1

Hi

Here is a variation. This will stop user from moving to next MTB if current one is not complete, and will auto move to next one if complete.

' MaskedTextBoxes
Option Strict On
Option Explicit On
Public Class Form1
	WithEvents mtb As MaskedTextBox
	WithEvents tb As New TextBox
	Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
		' set up some (4) maskedtextboxes
		Dim x As Integer = 10
		Dim y As Integer = 20
		For i As Integer = 1 To 4
			mtb = New MaskedTextBox
			With mtb
				.Name = "MaskedTextBox" & i.ToString
				.BackColor = Color.Pink
				.Tag = i
				.Mask = "00 - 00 - 00"
				.Font = New Font(.Font.FontFamily, 18)
				.TextAlign = HorizontalAlignment.Center
				.Location = New Point(10, y)
				.Width = 200
				y += 44
				AddHandler .Validated, AddressOf MaskedTextBox_Validated
				AddHandler .KeyUp, AddressOf MaskedTextBox_KeyUp
			End With
			Controls.Add(mtb)
		Next

		' add a random textbox
		With tb
			.Font = New Font(.Font.FontFamily, 18)
			.Text = "Some random text"
			.Location = New Point(10, y + 10)
			.BackColor = Color.WhiteSmoke
			.Width = 200
		End With
		Controls.Add(tb)
	End Sub
	Private Sub MaskedTextBox_Validated(sender As Object, e As EventArgs)
		' checks if current MTB is complete
		' if not, remain there.
		Dim mtb As MaskedTextBox = DirectCast(sender, MaskedTextBox)
		tb.Text = String.Empty
		If Not mtb.MaskFull Then
			tb.Text = mtb.Text
			MessageBox.Show(mtb.Name & " Needs full Sort Code")
			mtb.Select()
		End If
	End Sub

	Private Sub MaskedTextBox_KeyUp(sender As Object, e As KeyEventArgs)
		' checks if current MTB is full and
		' if so, moves to next which
		' ends at the random TextBox
		Dim mtb As MaskedTextBox = DirectCast(sender, MaskedTextBox)
		If mtb.MaskFull Then
			SendKeys.Send(vbTab)
		End If
	End Sub
End Class

Answer 2

Hi

Here is a test example which demonstrates all the features I think you want. It is set to add multiple MaskedTextBoxes, and to auto jump to next when each one is completed and jump to 'regular' textbox hen all are completed. Just to illustrate use of the MaskedTextBox.MaskCompleted event.

' MaskedTextBoxes
Option Strict On
Option Explicit On
Public Class Form1
	WithEvents mtb As MaskedTextBox
	WithEvents tb As New TextBox
	Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
		' set up some (4) maskedtextboxes
		Dim x As Integer = 10
		Dim y As Integer = 20
		For i As Integer = 1 To 4
			mtb = New MaskedTextBox
			With mtb
				.Name = "MaskedTextBox" & i.ToString
				.BackColor = Color.Pink
				.Tag = i
				.Mask = "00 - 00 - 00"
				.Font = New Font(.Font.FontFamily, 18)
				.TextAlign = HorizontalAlignment.Center
				.Location = New Point(10, y)
				.Width = 200
				y += 44
				AddHandler .TextChanged, AddressOf MaskedTextBox_TextChanged
			End With
			Controls.Add(mtb)
		Next

		' add a random textbox
		With tb
			.Font = New Font(.Font.FontFamily, 18)
			.Text = "Some random text"
			.Location = New Point(10, y + 10)
			.BackColor = Color.WhiteSmoke
			.Width = 200
		End With
		Controls.Add(tb)
	End Sub
	Private Sub MaskedTextBox_TextChanged(sender As Object, e As EventArgs)
		Dim mtb As MaskedTextBox = DirectCast(sender, MaskedTextBox)
		Dim found As Boolean = False
		If mtb.MaskCompleted Then
			Console.Beep(1200, 40)
			Dim ind As Integer = CInt(mtb.Tag) + 1
			For Each c As Control In Me.Controls
				If c.GetType = GetType(MaskedTextBox) Then
					If CInt(c.Tag) = ind Then
						found = True
						c.Select()
					End If
				End If
			Next
			If Not found Then
				' reached last one - what to do?
				' here I just activate the textbox
				tb.Select()
			End If
		End If
	End Sub
End Class

Answer 3

Hello Gary,

not up to date on my VB skills, but if I remember correctly you can user the Textbox.MaskCompleted property to check for true (filled) or false (null/empty).

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