properties - What editor to use for a Custom Property that is a list of datagridviewcolumns?

Question

I want to have a custom property to a custom class based on the datagridviewcolumn class. I want a property that is a list of datagridvewcolumns and I want to be able to select the columns at design time. What would be a good way to acheive this? I feel like I am making this more complicated than it needs to be.

Here is what I have done so far. I can successfully make a property that is a single datagridviewcolumn that provides a dropdown to select from available columns at design time using a custom objectselectoreditor and overrriding the filltreewithdata function to fill the list with all datagridviewcolumns in the form. However I am having trouble expanding on this to use a property that is a list of columns. The default editor brings up a collection editor that then creates a new datagridviewcolumn entry with all the datagridviewcolumn proroperties instead of just a dropdown to chose from a list.

The closest I have gotten is by creating a custom editor inherited from the collection object editor. The editor then uses a "custom class" with datagridviewcolumn property that uses the objectselectoreditor that then provides the list to select from for each new entry in the collection. At this point, I receive and error that it cannot cast the "custom class" to datagridviewcolumn. So I tried to override the getitems and setitems functions so the editor would return a list of just the datagridviewcolumn property of the custom class items. At this point I get an error when building the solution that the datagridviewcolumn object is not marked as serializable.

Below is my code: The Property from the custom column class

    ''' <summary>
    ''' A List of specific DGVColumns from the associated Datagridview Control.
    ''' </summary>
    ''' <returns></returns>
    <Editor(GetType(MyDataGridViewColumnListEditor), GetType(Drawing.Design.UITypeEditor))>
    Public Property TestDGVColList As List(Of DataGridViewColumn)
        Get
            Return lstTestDGVColList
        End Get
        Set(value As List(Of DataGridViewColumn))
            lstTestDGVColList = value
        End Set
    End Property 

The code for the editors

    Inherits CollectionEditor
    <Browsable(False), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)>
    Public Property CurrentDataGridViewColumn As DataGridViewColumn
    Public Sub New()

        MyBase.New(type:=GetType(List(Of SelectedDataGridViewColumnItem)))

    End Sub

    Public Overrides Function EditValue(context As ITypeDescriptorContext, provider As IServiceProvider, value As Object) As Object
        CurrentDataGridViewColumn = context.Instance.datagridviewcolumn
        Return MyBase.EditValue(context, provider, value)
    End Function

    Protected Overrides Function GetItems(editValue As Object) As Object()
        Dim lst As New List(Of Object)

        If editValue IsNot Nothing Then
            For Each sdgvci As DataGridViewColumn In editValue

                lst.Add(New SelectedDataGridViewColumnItem With {.CurrentDataGridViewColumn = CurrentDataGridViewColumn, .DataGridViewColumn = sdgvci})
            Next
            Return lst.ToArray

        Else
            Return MyBase.GetItems(editValue)
        End If

    End Function

    Protected Overrides Function SetItems(editValue As Object, value() As Object) As Object
        Dim lst As New List(Of DataGridViewColumn)

        For Each sdgvci As SelectedDataGridViewColumnItem In value

            lst.Add(sdgvci.DataGridViewColumn)
        Next
        Return lst
    End Function
    Protected Overrides Function CreateInstance(itemType As Type) As Object

        Dim obj As Object = MyBase.CreateInstance(itemType)
        CType(obj, SelectedDataGridViewColumnItem).CurrentDataGridViewColumn = CurrentDataGridViewColumn
        Return obj

    End Function


    Class SelectedDataGridViewColumnItem
        <Editor(GetType(MyDataGridViewColumnSelectionEditor), GetType(Drawing.Design.UITypeEditor))>
        Public Property DataGridViewColumn As DataGridViewColumn
        <Browsable(False), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)>
        Public Property CurrentDataGridViewColumn As DataGridViewColumn

        Sub New()

        End Sub
    End Class
End Class

Public Class MyDataGridViewColumnSelectionEditor
    Inherits ObjectSelectorEditor

    Protected Overrides Sub FillTreeWithData(ByVal theSel As Selector, ByVal theCtx As ITypeDescriptorContext, ByVal theProvider As IServiceProvider)
        MyBase.FillTreeWithData(theSel, theCtx, theProvider)
        Dim dgvcType As Type = GetType(DataGridViewColumn)

        Try
            For Each dgvcol As DataGridViewColumn In CType(theCtx.Instance.CurrentDataGridViewColumn.datagridview, DataGridView).Columns
                If dgvcType.IsAssignableFrom(dgvcol.GetType) Then
                    Try
                        Dim [aNd] As SelectorNode = New SelectorNode(dgvcol.HeaderText & " - " & dgvcol.Name, dgvcol)
                        theSel.Nodes.Add([aNd])
                        theSel.Sort()
                    Catch ex As Exception
                    End Try
                End If
            Next
        Catch ex As Exception
        End Try
    End Sub
End Class

Answer 1

等待大神答复