ComboBox - MultiColumn

mikasa

Hello, I am trying to find out if anyone has a ComboBox Control for Visual Basic .NET that will handle Multi-Columns. Also, I have seen a Drop-Down TreeView Control as well on this site...has anyone Implemented this into .NET yet? I could really use both of these ASAP!

Richard Deeming

I've got multi-column data-bound ComboBox and ListBox controls, with support for column images and gridlines. They're very easy to do, so I don't think they're worth an article. Let me know if you want me to post the code here. :-D

Richard Deeming

I'll split this code up over several messages. First, define the Data column object:

Imports System.ComponentModel
Imports System.Drawing

<ToolboxItem(""), DesignTimeVisible(False)> _
Public Class DataColumn : Inherits Component

Protected Shared \_StringFormatter As StringFormat
Shared Sub New()
    \_StringFormatter = New StringFormat()
    With \_StringFormatter
        .Trimming = StringTrimming.EllipsisCharacter
        .FormatFlags = StringFormatFlags.NoWrap
        .LineAlignment = StringAlignment.Center
    End With
End Sub

#Region "Member Vars"
Private _Image As Image
Private _DataMember As String
Private _Tag As Object
Private _Width As Integer
Private _Parent As DataColumnCollection
#End Region

#Region "Constructors"
Public Sub New()
_Image = Nothing
_Width = 75
_DataMember = String.Empty
_Tag = Nothing
End Sub
Public Sub New(ByVal Image As Image)
_Image = Image
_Width = 22
_DataMember = String.Empty
_Tag = Nothing
End Sub
Public Sub New(ByVal DataMember As String)
_Image = Nothing
_Width = 75
_DataMember = DataMember
_Tag = Nothing
End Sub
Public Sub New(ByVal Width As Integer)
_Image = Nothing
_Width = Width
_DataMember = String.Empty
_Tag = Nothing
End Sub
Public Sub New(ByVal DataMember As String, ByVal Width As Integer)
_Image = Nothing
_Width = Width
_DataMember = DataMember
_Tag = Nothing
End Sub
Public Sub New(ByVal Image As Image, _
ByVal DataMember As String, _
ByVal Width As Integer)
_Image = Image
_Width = Width
_DataMember = DataMember
_Tag = Nothing
End Sub
#End Region

Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
    If disposing Then
        If Not (\_Image Is Nothing) Then
            Try
                \_Image.Dispose()
            Finally
                \_Image = Nothing
            End Try
        End If
    End If
    MyBase.Dispose(disposing)
End Sub

#Region "Properties"
<Editor("System.Windows.Forms.Design.DataMemberFieldEditor", _
"System.Drawing.Design.UITypeEditor"), _
Category("Behavior")> _
Public Overridable Property DataMember() As Strin

Richard Deeming

Next, define a collection of DataColumns:

Imports System.ComponentModel
Imports System.Collections
Imports System.Windows.Forms

Public Class DataColumnCollection : Inherits CollectionBase

Private \_Parent As Control

#Region "Constructors"
Public Sub New()
'Do Nothing
End Sub
Public Sub New(ByVal Value() As DataColumn)
AddRange(Value)
End Sub
Public Sub New(ByVal Value As DataColumnCollection)
AddRange(Value)
End Sub
#End Region

#Region "Add"
Public Function Add(ByVal Value As DataColumn) As Integer
Value.Parent = Me
Return List.Add(Value)
End Function
Public Sub AddRange(ByVal Value() As DataColumn)
Dim oItem As DataColumn
For Each oItem In Value
oItem.Parent = Me
List.Add(oItem)
Next
End Sub
Public Sub AddRange(ByVal Value As DataColumnCollection)
Dim oItem As DataColumn
For Each oItem In Value
oItem.Parent = Me
List.Add(oItem)
Next
End Sub
#End Region

Public Function Contains(ByVal Value As DataColumn) As Boolean
    Return List.Contains(Value)
End Function
Public Sub CopyTo(ByVal array() As DataColumn, ByVal index As Integer)
    List.CopyTo(array, index)
End Sub
Public Overloads Function IndexOf(ByVal Value As DataColumn) As Integer
    Return List.IndexOf(Value)
End Function
Public Sub Insert(ByVal index As Integer, ByVal Value As DataColumn)
    List.Insert(index, Value)
End Sub

Default Public Property Item(ByVal index As Integer) As DataColumn
    Get
        Return DirectCast(List.Item(index), DataColumn)
    End Get
    Set(ByVal Value As DataColumn)
        List.Item(index) = Value
    End Set
End Property


Protected Overrides Sub OnInsert(ByVal index As Integer, \_
                                            ByVal Value As Object)

    If TypeOf Value Is DataColumn Then
        MyBase.OnInsert(index, Value)
        DirectCast(Value, DataColumn).Parent = Me
    Else
        Throw New ArgumentException()
    End If
End Sub

Protected Overrides Sub OnSet(ByVal index As Integer, \_
                                        ByVal OldValue As Object, \_
                                        ByVal NewValue As Object)

    If TypeOf NewValue Is DataColumn Then
        MyBase

Richard Deeming

Next, a base for the ComboBox / ListBox:

Imports System.Drawing
Imports System.Windows.Forms
Imports System.ComponentModel

Public Class ComboBoxEx : Inherits ComboBox
'Or - Public Class ListBoxEx : Inherits ListBox
Protected HighlightBrush As Brush
Protected HighlightPen As Pen

#Region "Constructors"
Public Sub New()
DrawMode = DrawMode.OwnerDrawFixed
ItemHeight += 1
HighlightBrush = New SolidBrush(SystemColors.Highlight)
HighlightPen = New Pen(SystemColors.HighlightText)
End Sub
#End Region

#Region "Overrides"
Protected Overrides Sub OnDrawItem(ByVal e As DrawItemEventArgs)
If Not (e.Index = -1) Then
DrawListBoxItem(e)
End If
End Sub

Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
    If disposing Then
        HighlightBrush.Dispose()
        HighlightPen.Dispose()
    End If
    MyBase.Dispose(disposing)
End Sub

<Browsable(False)> \_
Public Shadows Property DrawMode() As DrawMode
    Get
        Return MyBase.DrawMode
    End Get
    Set(ByVal Value As DrawMode)
        MyBase.DrawMode = Value
    End Set
End Property

#End Region

#Region "Implementation"
Protected Sub DrawListBoxItem(ByVal e As DrawItemEventArgs)
'// Draw List box item
If Enabled AndAlso _
((e.State And DrawItemState.Selected) = DrawItemState.Selected) Then

        DrawItemHighlight(e)
    Else
        DrawItemClearHighlight(e)
    End If
    DrawItemText(e)
End Sub

Protected Overridable Sub DrawItemText(ByVal e As DrawItemEventArgs)
    Dim currentObject As Object = Items(e.Index)
    Dim item As String = GetItemText(currentObject)
    If Not (item Is Nothing) Then
        Dim B As Brush
        If Enabled Then
            B = New SolidBrush(e.ForeColor)
        Else
            B = SystemBrushes.ControlDark
        End If

        e.Graphics.DrawString(item, \_
                e.Font, \_
                B, \_
                New PointF(e.Bounds.Left + 2, e.Bounds.Top))

        If Enabled Then B.Dispose()
    End If
End Sub

Protected Overridable Sub DrawItemHighlight(ByVal e As DrawItemEventArgs)
    Dim g As Graphics = e.Graphics
    Dim b As Rectangle = e.Bounds
    g.FillRectangle(HighlightBrush, b)
    g.DrawRectangle(Highli

Richard Deeming

Finally, define the List/ComboBox:

Imports System.Drawing
Imports System.Windows.Forms
Imports System.ComponentModel

<DesignerCategory("Component"), _
DefaultProperty("DataSource"), _
TypeConverter("System.Windows.Forms.Design.DataSourceConverter"), _
ToolboxItem(True)> _
Public Class DataComboBoxEx : Inherits ComboBoxEx
'Or - Public Class DataListBoxEx : Inherits ListBoxEx

Private \_Columns As DataColumnCollection
Private \_GridLineColor As Color
Private \_ShowHorizontalGridLines As Boolean
Private \_ShowVerticalGridLines As Boolean

Public Sub New()
    \_ShowVerticalGridLines = True
    \_ShowHorizontalGridLines = False
    \_Columns = New DataColumnCollection()
    \_Columns.Parent = Me

    \_GridLineColor = SystemColors.ControlDark
    ItemHeight = Math.Max(ItemHeight, 22)
End Sub

Protected Overrides Sub DrawItemText( \_
        ByVal e As System.Windows.Forms.DrawItemEventArgs)

    Dim rItem As Rectangle = e.Bounds
    Dim g As Graphics = e.Graphics
    Dim gPen As New Pen(\_GridLineColor)
    Dim DS As Object
    If DataSource Is Nothing Then
        DS = Items
    Else
        DS = DataSource
    End If

    Dim rItemF As New RectangleF(rItem.X, rItem.Y, rItem.Width, rItem.Height)
    Dim oItem As DataColumn
    For Each oItem In \_Columns
        rItemF.Width = oItem.Width
        oItem.OnDraw(e, rItemF, DS, DisplayMember)
        If \_ShowVerticalGridLines Then
            g.DrawLine(gPen, rItemF.Right, rItemF.Y, rItemF.Right, rItemF.Bottom)
        End If
        rItemF.X += rItemF.Width
    Next
    If \_ShowHorizontalGridLines Then
        g.DrawLine(gPen, rItem.X, rItem.Bottom - 1, rItem.Right, rItem.Bottom - 1)
    End If

    gPen.Dispose()
End Sub

<Category("Behavior"), \_
DesignerSerializationVisibility(DesignerSerializationVisibility.Content)> \_
Public Property Columns() As DataColumnCollection
    Get
        Return \_Columns
    End Get
    Set(ByVal Value As DataColumnCollection)
        \_Columns = Value
        \_Columns.Parent = Me
    End Set
End Property

<Category("Appearance")> \_
Public Property GridLineColor() As Color
    Get
        Return \_GridLineColor
    End Get
    Set(ByVal Value As Color)
        \_GridLineColor = Value
    End Set
End Property

mikasa

Ok, this is good. It will probably take some time for me to evaluate everything here. Will this support "unbound" data as well? Thanks a lot! :-D

Richard Deeming

It should do - if you don't specify a data source, it will use the Items property, which implements IList, so it should pick up the items from that.

mikasa

Hey, thanks for the help a while back! I was wondering if you could maybe send me the ".vb" file as an attachment to my email address. The formatting on this website when I copy and paste is horrendous! Greatly appreciated!