Custom UserControl-based comp component now cannot be dropped on form.

[TheBugSlayer]

Dear fellows,

I have been running into this program since morning. I am developing a component which derives from UserControl and includes a MaskedTextBox and a DateTimePicker. It was all working fine until earlier today when I added two new properties and rebuilt the component. From that moment on, when I tried to drop the component on a form it fails with error "Failed do create component 'NullableDateTime'. The error message follows: 'System.InvalidCastException: Conversion from string 'NullableDateTime1' to 'Date' is not valid...". Please refer to attached image file for complete error description. Oops, sorry, company prohibits uploads...hopefully that is descriptive enough.

Below is the complete code of my Windows Class Library in NullableDateTime.vb:

Imports System.ComponentModel

Public Class NullableDateTime
    Inherits System.Windows.Forms.UserControl


    Public Event OnValueChanged(ByVal Sender As System.Object, ByVal e As EventArgs)

    Private mAssignedFromMaskedTextBox As Boolean = False

    Private mCDay As String = "01"
    <Description("Fixed day in date."), Browsable(True), Category("Custom")> _
    Public Property CDay() As String
        Get
            Return mCDay
        End Get
        Set(ByVal value As String)
            mCDay = value
        End Set
    End Property
    Private mCMonth As String = "01"
    <Description("Fixed month in date."), Browsable(True), Category("Custom")> _
    Public Property CMonth() As String
        Get
            Return mCMonth
        End Get
        Set(ByVal value As String)
            If value >= 1 And value <= 12 Then
                mCMonth = value
            Else
                mCMonth = 12
            End If
        End Set
    End Property
    Private mCYear As String = "2007"
    <Description("Fixed month in date."), Browsable(True), Category("Custom")> _
    Public Property CYear() As String
        Get
            Return mCYear
        End Get
        Set(ByVal value As String)
            mCYear = value
        End Set
    End Property
    Private mUseConstants As Boolean = True
    <Description("Determines whether to use fixed values for day, month and year."), Browsable(True), Category("Custom")> _
    Public Property UseConstants() As Boolean
        Get
            Return mUseConstants
        End Get
        Set(ByVal value As Boolean)
            mUseConstants = value
        End Set
    End Property
    Private mText As String = String.Empty
    <Description("The text (value) of the masked text box."), Browsable(True), Category("Custom")> _
    Public Overrides Property Text() As String
        Get
            'Return mText
            Return DateTimePicker.Value
        End Get
        Set(ByVal Value As String)
            mText = Value
            'We don't validate but DateTimePicker takes care of it.
            'This assigns to MaskedTextBox too eventually by way of ValueChanged event
            If DateTimePicker.Value.ToShortDateString().Equals(Value) Then
                MaskedTextBox.Text = DateTimePicker.Value.ToString(System.Globalization.CultureInfo.InvariantCulture)
            Else
                mAssignedFromMaskedTextBox = False
                DateTimePicker.Value = Value
            End If
            Dim e As New System.EventArgs
            RaiseEvent OnValueChanged(Me, e)
        End Set
    End Property
    Private mCustomeDateTimeFormat As String = String.Empty
    '<Description("The custom format of the embedded DateTimePicker."), Browsable(True), Category("Custom")> _
    'Public Property CustomDateTimeFormat() As String
    '    Get
    '        Return mCustomeDateTimeFormat
    '    End Get
    '    Set(ByVal value As String)
    '        mCustomeDateTimeFormat = CustomDateTimeFormat
    '        DateTimePicker.CustomFormat = mCustomeDateTimeFormat
    '    End Set
    'End Property
    Private mDateTimeFormat As DateTimePickerFormat = DateTimePickerFormat.Short
    '<Description("The format of the embedded DateTimePicker."), Browsable(True), Category("Custom")> _
    'Public Property DateTimeFormat() As DateTimePickerFormat
    '    Get
    '        Return mDateTimeFormat
    '    End Get
    '    Set(ByVal value As DateTimePickerFormat)
    '        mDateTimeFormat = DateTimeFormat
    '        DateTimePicker.Format = mDateTimeFormat
    '    End Set
    'End Property

    Public Sub DateTimePicker_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
    Handles DateTimePicker.ValueChanged
        DateTimePicker.Value = CDate(DatePart(DateInterval.Month, DateTimePicker.Value).ToString() & _
                               "/" & CDay.ToString() & "/" & _
                               DatePart(DateInterval.Year, DateTimePicker.Value).ToString())

        If Not mAssignedFromMaskedTextBox Then
            MaskedTextBox.Text = DateTimePicker.Value.ToString(System.Globalization.CultureInfo.InvariantCulture)
        End If
        RaiseEvent OnValueChanged(sender, e)
    End Sub
    Private Sub NullableDateTime_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Enter, MyBase.Leave
        mAssignedFromMaskedTextBox = False
        DateTimePicker.Value = CDate(DatePart(DateInterval.Month, DateTimePicker.Value).ToString() & _
                               "/" & CDay.ToString() & "/" & _
                               DatePart(DateInterval.Year, DateTimePicker.Value).ToString())

    End Sub
    Private Sub DateTimePicker_Leave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DateTimePicker.Leave
        'Unfortunately DateTimePicker doesn't provide a CheckedChanged event, which would
        'be the best place for this check.
        Dim NextCtrl As New Control
        If Not DateTimePicker.Checked Then
            MaskedTextBox.Text = String.Empty
            'MessageBox.Show(Me.ParentForm.Name & " <--Parent: " & "Me : " & Me.Name & "  Next-->" & Me.ParentForm.GetNextControl(Me, True).Name)
            With Me.ParentForm.GetNextControl(Me, True)
                If CanFocus Then
                    .Focus()
                ElseIf .CanSelect Then
                    .Select()
                End If
            End With

        End If
    End Sub
    Private Sub MaskedTextBox_Validating(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MaskedTextBox.Validating
        If MaskedTextBox.Text.Trim.Equals("/  /") Then
            DateTimePicker.Checked = False
        Else
            'This will force validation through date time picker.
            mAssignedFromMaskedTextBox = True
            DateTimePicker.Value = MaskedTextBox.Text
        End If
    End Sub
    Private Sub MaskedTextBox_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MaskedTextBox.TextChanged
        RaiseEvent OnValueChanged(sender, e)
    End Sub
    Public Function IsNull() As Boolean
        Return MaskedTextBox.Text.Trim.Equals("/  /")
    End Function



End Class

Suggestions ARE welcome. Been stuck on this component for three days...deadline approaching. You may uncomment the two properties, it doesn't make a difference. Thanks!

 

[TheBugSlayer]

Oh, sorry, wrong forum...Will post in VB.NET...