Tag Archives: Tips

Set DateTimePicker control value to Null

I achieve this by handling the Binding Source that the control is binding to and enabling the ShowCheckBox property.

The .NET DateTimePicker doesn’t accept blank or NULL value. I’ve seen many posts online that extend the controller to accept NULL value like this one or some other posts to change the formatting to custom and switching back again.

So if you don’t feel like adding a new custom control to your project just handle the underlying data source.

DateTimePicker with CheckBoxesSince I had many of the DateTimePicker controls, I made one function that handles the Leave event of each one like so:

    Private Sub DateTimePicker_Leave(sender As System.Object, e As System.EventArgs) Handles Inv_OriginalDateTimePicker.Leave
        'Handle the DateTimePicker so when it is unchecked it saves Null value
        Dim dt As DateTimePicker = sender

        If Not dt.Checked Then
            'Get the current record
            Dim row = DirectCast(Me.PO_JobsBindingSource.Current, DataRowView)

            row(dt.DataBindings.Item("Value").BindingMemberInfo.BindingField.ToString) = DBNull.Value

        End If
    End Sub

Moving items between bound Listboxes

The other day I wanted to add news tags feature to a program, and to make it easy I wanted the user to be able of adding and removing news tags by double clicking a Listbox of available tags and assigned tags.

How I wanted Listboxes Tags to work

If you need to move items between bound Listboxes you cannot just use the Listbox.Add or Listbox.Remove methods. Instead you should add and remove rows to the Tables which they’re bound to.

This is the code I used:

    Private Sub AvailableTagListBox_DoubleClick(sender As System.Object, e As System.EventArgs) Handles AvailableTagListBox.DoubleClick
        If Not IsNothing(AvailableTagListBox.SelectedItem) Then
            'We are making a new row to be added to the table which then will appear in the listbox
            Dim Customer_News_Tags_Row As DataRow = MyDataSet.Customer_News_Tags.NewRow
            'Since I have a Parent and Child relation I'm taking the current parent ID
            Dim NewsRow = DirectCast(Me.Customer_NewsBindingSource.Current, DataRowView)
            'Parent ID
            Customer_News_Tags_Row("News_ID") = NewsRow("ID")
            'Fill the listbox item display field which I have it bound to
            Customer_News_Tags_Row("Tag") = AvailableTagListBox.Text

            'Adding new item to the other listbox by adding new row to its table
            'Delete the listbox item by deleting the row in its table
            MyDataSet.News_Tags.Select("ID=" & AvailableTagListBox.SelectedValue)(0).Delete()

        End If

    End Sub

    Private Sub AssignedTagListBox_DoubleClick(sender As System.Object, e As System.EventArgs) Handles AssignedTagListBox.DoubleClick
        If Not IsNothing(AssignedTagListBox.SelectedItem) Then

            Dim News_Tags_Row As DataRow = MyDataSet.News_Tags.NewRow
            'I'm using a field called Tag
            News_Tags_Row("Tag") = AssignedTagListBox.Text

            'Here I'm matching with a field I have called Tag to delete from Assigned listbox items
            MyDataSet.Customer_News_Tags.Select("Tag='" & AssignedTagListBox.SelectedValue & "'")(0).Delete()

        End If
    End Sub

Hope this helps, and if you need any clarifications let me know 🙂


Move project to another Visual Studio Online account

Let’s say you have a project source hosted in your private Visual Studio Online (Team Foundation Service) account and you want to move it to another account. The easiest way I found is to connect to the new account from Visual Studio (File->Connect to Team Project) and add the items to the source control:

TFS Add Items

Assuming you already have the source on your computer, just select them to be added. Also It will ask you to map a new work space for this new source:

TFS Map WorkSpace

Hit finish and then you are ready to check in the files.

I’ve been using Visual Studio Online for few months now since it was in beta when it was called Team Foundation Service and I totally love it!

The service gives you the ability to collaborate for free for up to 5 members and then you need to license users. I used it to collaborate with a friend and it gave us great help and it was very easy to use. Even though it is great for collaboration but I think you can use it also on your own for good maintenance.


GameMaker Studio with Visual Studio 2013 settings

If you are trying to use GamerMaker Studio wih Visual Studio 2013 and getting the error Unable to validate WinJS API Reference even though you prepared the requirements you have to change the settings to point to Visual Studio 2013 directory and change the WinJS version to 2 like in the following screenshot:

Game Maker VS2013

Note that I have pointed the Windows SDk to 8.1 since I’ve got Windows 8.1.



Editable bound DataGridView ComboBox

A bound DataGridView ComboBox Column doesn’t allow user input. You might come across a situation where you need to make it easier for the user to select an item from the ComboBox and at the same time allow them to just enter free text.

The trick is to make the ComboBox column without a DataSource and then you load the items by code. Also you have to handle a couple of stuff such as the EditingControlShowing event to convert the ComboBox style to be DropDown instead of DropDownList, and some other handling to commit the ComboBox change.

I will leave you with the code:

Private Sub MyForm_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

    'Get ComboBox items

    'Fill the ComboBox
    Dim row As DataRow
    For Each row In Me.MyDataSet.ComboBoxTable
        'Generic list used as a trick to have the ComboBox Items added with Value
        MyComboBox.Items.Add(New GenericListItem(Of String)(row.Item("ColName"), row.Item("ColValue")))



    'Adding Grid handler to detect change in run time
    AddHandler MyDataGridView.CurrentCellDirtyStateChanged, AddressOf MyDataGridView_CurrentCellDirtyStateChanged

End Sub

'Change ComboBox style to DropDown
  Private MyDataGridView_EditingControlShowing(ByVal sender As Object, ByVal e As MyDataGridViewEditingControlShowingEventArgs) Handles MyDataGridView.EditingControlShowing
        If TypeOf e.Control Is ComboBox Then
Dim cb As ComboBox = TryCast(e.Control, ComboBox)

            cb.DropDownStyle = ComboBoxStyle.DropDown
        End If

'When an item is selected from the ComboBox update the cell value
        If MyDataGridView.Columns(MyDataGridView.CurrentCell.ColumnIndex).Name = "MyComboBox" Then
Dim selectedComboBox As ComboBox = DirectCast(e.Control, ComboBox)
            RemoveHandler selectedComboBox.SelectionChangeCommitted, AddressOf selectedComboBox_SelectionChangeCommitted
            AddHandler selectedComboBox.SelectionChangeCommitted, AddressOf selectedComboBox_SelectionChangeCommitted

        End If

    End Sub

Private Sub selectedComboBox_SelectionChangeCommitted(ByVal sender As Object, ByVal e As EventArgs)

        Dim selectedCombobox As ComboBox = DirectCast(sender, ComboBox)
        If selectedCombobox.SelectedItem IsNot Nothing Then

            'Use the List we created earlier so we could retrieve the Value instead of the diplayed text
            Dim oItem As GenericListItem(Of String) = CType(selectedCombobox.SelectedItem, GenericListItem(Of String))

            Me.MyDataGridView.Item("ColumnName", MyDataGridView.CurrentCell.RowIndex).Value = oItem.Value()

        End If

    Catch ex As Exception

    End Try
End Sub

Private Sub MyDataGridView_CurrentCellDirtyStateChanged(ByVal sender As Object, ByVal e As EventArgs) Handles MyDataGridView.CurrentCellDirtyStateChanged
    'Commit the change which was in run time so the Value changed event happens and then allow one check box
    If MyDataGridView.IsCurrentCellDirty Then
    End If
End Sub

Private Sub MyDataGridView_CellValidating(sender As Object, e As System.Windows.Forms.MyDataGridViewCellValidatingEventArgs) Handles MyDataGridView.CellValidating

    'Allow user to enter new values for all MyDataGridViewComboBox controls in the MyDataGridView
    If (TypeOf CType(sender, MyDataGridView).EditingControl Is MyDataGridViewComboBoxEditingControl) Then
        Dim cmb As MyDataGridViewComboBoxEditingControl = CType(CType(sender, MyDataGridView).EditingControl, MyDataGridViewComboBoxEditingControl)
        If Not cmb Is Nothing Then
            Dim grid As MyDataGridView = cmb.EditingControlMyDataGridView
            Dim value As Object = cmb.Text
            '// Add value to list if not there
            If cmb.Items.IndexOf(value) = -1 Then
                '// Must add to both the current combobox as well as the template, to avoid duplicate entries...
                Dim cmbCol As MyDataGridViewComboBoxColumn = CType(grid.Columns(grid.CurrentCell.ColumnIndex), MyDataGridViewComboBoxColumn)
                If Not cmbCol Is Nothing Then
                End If
            End If
            grid.CurrentCell.Value = value
        End If
    End If

    ''Following Works for a specific combobox ///////////

    'If e.ColumnIndex = MyMyDataGridView.Columns("MyDataGridViewComboBoxColSize").Index Then 'CType(sender, MyDataGridView).CurrentCell.ColumnIndex

    ' 'Dim cmb As ComboBox = CType(e.Control, ComboBox)

    ' Dim cmb As MyDataGridViewComboBoxEditingControl = CType(CType(sender, MyDataGridView).EditingControl, MyDataGridViewComboBoxEditingControl)

    ' If Not cmb Is Nothing Then

    ' Dim grid As MyDataGridView = cmb.EditingControlMyDataGridView

    ' Dim value As Object = cmb.Text

    ' '// Add value to list if not there

    ' If cmb.Items.IndexOf(value) = -1 Then

    ' '// Must add to both the current combobox as well as the template, to avoid duplicate entries...

    ' cmb.Items.Add(value)

    ' Dim cmbCol As MyDataGridViewComboBoxColumn = CType(grid.Columns(grid.CurrentCell.ColumnIndex), MyDataGridViewComboBoxColumn)

    ' If Not cmbCol Is Nothing Then

    ' cmbCol.Items.Add(value)

    ' End If

    ' grid.CurrentCell.Value = value

    ' End If

    ' End If

    'End If
End Sub

Public Class GenericListItem(Of T)
    Private mText As String
    Private mValue As T

    Public Sub New(ByVal pText As String, ByVal pValue As T)
        mText = pText
        mValue = pValue
    End Sub

    Public ReadOnly Property Text() As String
            Return mText
        End Get
    End Property

    Public ReadOnly Property Value() As T
            Return mValue
        End Get
    End Property

    Public Overrides Function ToString() As String
        Return mText
    End Function
End Class

I hope this helps, and if you have any question let me know.

Happy coding 🙂


Learn SharePoint 2010 without installations or top hardware

So you have decided you want to get into SharePoint, but you find out that you need to have a pretty strong machine to run it. Actually the latest SharePoint 2010 needs 6 GB of RAM as a starting point to run well and a 64 bit Windows 2008 operating system.

You could actually learn without installing a thing! Yes. Microsoft offers a great service called MSDN Virtual Labs.MSDN vlab Using these Virtual Labs you can test and try almost every Microsoft technology and product. And of course SharePoint Virtual Labs is one of them. In the Lab courses you get to learn and have hands-on experience. They even include software which you would need like SharePoint Designer. Really helpful.

So go on and have fun Smile