Public Class MyTb
    Enum ETFormat
        TimeHHMM = 1
        Normal = 0
    End Enum
    Private v_TextFormat As ETFormat = ETFormat.Normal


    Property TextFormat() As ETFormat
        Get
            Return v_TextFormat
        End Get
        Set(ByVal value As ETFormat)
            Me.v_TextFormat = value
        End Set
    End Property
    Dim NC As Control = Nothing

    Private Sub MyTb_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.GotFocus
        Me.SelectAll()
    End Sub
    Private Sub MyTb_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If e.KeyCode = Keys.Enter Then
            If Me.Text <> "" Then
                Dim Txt As String = Me.Text
                Select Case TextFormat
                    Case ETFormat.Normal
                    Case ETFormat.TimeHHMM
                        If Txt.IndexOf(":") = -1 Then
                            If IsNumeric(Txt) Then
                                Select Case Txt.Length
                                    Case 1
                                        Me.Text = "0" & Txt & ":00"
                                    Case 2
                                        Me.Text = Txt & ":00"
                                    Case 3
                                        Me.Text = Txt.Substring(0, 2) & ":" & Txt.Substring(2) & "0"
                                    Case 4
                                        Me.Text = Txt.Substring(0, 2) & ":" & Txt.Substring(2)
                                End Select
                            End If
                        End If
                End Select
            End If

            If Me.NC Is Nothing Then
                SendKeys.Send("{TAB}")
            Else
                NC.Focus()
            End If
        End If
    End Sub
    Public Property NectControl() As Control
        Get
            Return NC
        End Get
        Set(ByVal value As Control)
            NC = value
        End Set
    End Property
End Class