Winforms Databinding… not confusing at all

So you wanna use WinForms (e.g. natively or in a Word Add-In) in C# / VB? Great, there’s good support for databinding controls to objects. And it’s fucked until it works, then it’s great.

General rules

• Don’t trust the designer blindly

Data Source Setup

• Make some public classes, such as below.
• Note we inherit from BindingList

Public Class GlobalSettings
    Public Property Name As String
    Public Property Disciplines As New DisciplineList

    Public Class DisciplineList
        Inherits BindingList(Of Discipline)
    End Class

    Public Class Discipline
        Public Property Name As String

        Public Sub New()
        End Sub

        Public Sub New(name As String)
            Me.Name = name
        End Sub

        Public Overrides Function ToString() As String
                Return Me.Name
        End Function
        ' optional, for searching
        Public Overrides Function Equals(ByVal obj As Object) As Boolean
            Dim temp = TryCast(obj, Discipline)
            If temp IsNot Nothing Then
                Return Me.Name = temp.Name
            Else
                Return False
            End If
        End Function
        Public Shared Operator =(ByVal o1 As Discipline, ByVal o2 As     Discipline) As Boolean
            Return o1.Equals(o2)
        End Operator '
        Public Shared Operator <>(ByVal o1 As Discipline,
             ByVal o2 As Discipline) As Boolean
            Return Not (o1 = o2)
        End Operator
End Class

Form Bindings

• Add a Data Source->Object
• Drag it into the form (or pull a control in directly. note you can change default type)
• IMPORTANT! Manually add a record to the top-most datasource. “sub” datasources, such as a property (e.g. list) of the top-most datasource work without changes.

        Me.GlobalSettingsBindingSource.Clear()
        Me.GlobalSettingsBindingSource.Add(ThisAddIn.AddinGlobalSettings)

• For simple text, you can bind directly and it’s done in theory. The “DataSource” and “DisplayMember” (which control the list to choose from) seem to stick well. The In practice I find I sometimes need to manually add the (DataBindings) as follows:

Me.txtDefaultAuthor.DataBindings.Clear()
Me.txtDefaultAuthor.DataBindings.Add(New System.Windows.Forms.Binding("Text", My.Settings.Default, "DefaultAuthor", True, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged))
        

• For combobox values, load and write the selected value manual. This should probably work bound to a single value, but I run into problems. Instead, do it manually:

' Load Form:

        If Me.cbDefaultDiscipline.FindStringExact(My.Settings.DefaultDiscipline) > -1 Then
            Me.cbDefaultDiscipline.SelectedIndex = Me.cbDefaultDiscipline.FindStringExact(My.Settings.DefaultDiscipline)
        End If

' OK Button
        My.Settings.DefaultDiscipline = Me.cbDefaultDiscipline.SelectedValue.name