Multiple Selection
By default, RadMultiColumnComboBox allows single selection. Considering the DisplayMember property, the respective value from the assigned DataSource collection is displayed in the editable part when a certain row from the pop up grid is selected.
However, in some cases, it may be required to allow multiple selection, e.g. select business days during the week. The following tutorial demonstartes a sample approach how to achieve multiple selection in RadMultiColumnComboBox:
Figure 1: Multiple Selection in RadMultiColumnComboBox
1. Drag a RadMultiColumnComboBox control on the form and populate it with data by setting the DataSource property and specifying the DisplayMember and ValueMember properties. Create a RadMultiColumnComboBoxSelectionExtender class that inherits System.ComponentModel.Component. It will contain the whole logic for creating check boxes in the row header column of the pop up grid and creating tokens for the checked rows as well. You can find below a sample implementation:
RadMultiColumnComboBox's extender for multiple selection
[ToolboxItem(false)]
public class RadMultiColumnComboBoxSelectionExtender : System.ComponentModel.Component
{
private RadAutoCompleteBoxElement autoCompleteBoxElement;
private System.Collections.Generic.Dictionary<string, GridViewRowInfo> rows = new System.Collections.Generic.Dictionary<string, GridViewRowInfo>();
private RadMultiColumnComboBox associatedRadMultiColumnComboBox;
private Size originalSize = Size.Empty;
public RadAutoCompleteBoxElement AutoCompleteBoxElement
{
get
{
return this.autoCompleteBoxElement;
}
}
/// <summary>
/// Gets the tokenized items.
/// </summary>
public RadTokenizedTextItemCollection Items
{
get { return this.autoCompleteBoxElement.Items; }
}
public RadMultiColumnComboBox AssociatedRadMultiColumnComboBox
{
get
{
return this.associatedRadMultiColumnComboBox;
}
set
{
this.SetAssociatedRadMultiColumnComboBox(value);
}
}
private void SetAssociatedRadMultiColumnComboBox(RadMultiColumnComboBox radMultiColumnComboBox)
{
if (radMultiColumnComboBox == null && this.associatedRadMultiColumnComboBox != null)
{
this.SetAssociatedRadMultiColumnComboBoxCoreToNull();
}
this.SetAssociatedRadMultiColumnComboBoxCore(radMultiColumnComboBox);
}
private void SetAssociatedRadMultiColumnComboBoxCoreToNull()
{
this.associatedRadMultiColumnComboBox.HandleCreated -= associatedRadMultiColumnComboBox_HandleCreated;
this.associatedRadMultiColumnComboBox.DataBindingComplete -= associatedRadMultiColumnComboBox_DataBindingComplete;
this.associatedRadMultiColumnComboBox.EditorControl.ViewCellFormatting -= EditorControl_ViewCellFormatting;
this.associatedRadMultiColumnComboBox.DropDownClosing -= radMultiColumnCombobox1_DropDownClosing;
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.Visibility = ElementVisibility.Visible;
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.Children[2].Children.Remove(autoCompleteBoxElement);
this.autoCompleteBoxElement.MaxSize = new Size(0, 0);
this.autoCompleteBoxElement.AutoCompleteDataSource = null;
this.associatedRadMultiColumnComboBox.AutoSize = false;
this.associatedRadMultiColumnComboBox.Size = this.originalSize;
foreach (GridViewRowInfo item in this.associatedRadMultiColumnComboBox.EditorControl.Rows)
{
item.Tag = null;
}
this.autoCompleteBoxElement.Items.CollectionChanged -= Items_CollectionChanged;
this.autoCompleteBoxElement.CreateTextBlock -= autoCompleteBoxElement_CreateTextBlock;
this.autoCompleteBoxElement.TokenValidating -= autoCompleteBoxElement_TokenValidating;
this.autoCompleteBoxElement.Text = this.associatedRadMultiColumnComboBox.Text;
this.autoCompleteBoxElement.KeyDown -= autoCompleteBoxElement_KeyDown;
this.associatedRadMultiColumnComboBox = null;
this.rows.Clear();
}
private void SetAssociatedRadMultiColumnComboBoxCore(RadMultiColumnComboBox radMultiColumnComboBox)
{
if (radMultiColumnComboBox == null)
{
return;
}
this.originalSize = radMultiColumnComboBox.Size;
this.associatedRadMultiColumnComboBox = radMultiColumnComboBox;
this.associatedRadMultiColumnComboBox.AutoSize = true;
this.associatedRadMultiColumnComboBox.ThemeNameChanged += associatedRadMultiColumnComboBox_ThemeNameChanged;
this.associatedRadMultiColumnComboBox.HandleCreated += associatedRadMultiColumnComboBox_HandleCreated;
this.associatedRadMultiColumnComboBox.DataBindingComplete += associatedRadMultiColumnComboBox_DataBindingComplete;
this.associatedRadMultiColumnComboBox.DropDownStyle = RadDropDownStyle.DropDownList;
this.associatedRadMultiColumnComboBox.EditorControl.ViewCellFormatting += EditorControl_ViewCellFormatting;
this.associatedRadMultiColumnComboBox.DropDownClosing += radMultiColumnCombobox1_DropDownClosing;
this.autoCompleteBoxElement = new RadAutoCompleteBoxElement();
this.autoCompleteBoxElement.MinSize = new Size(150, 24);
this.autoCompleteBoxElement.Multiline = true;
this.autoCompleteBoxElement.DrawBorder = false;
this.autoCompleteBoxElement.KeyDown += autoCompleteBoxElement_KeyDown;
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ArrowButton.ZIndex = 1;
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.Visibility = ElementVisibility.Hidden;
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.Children[2].Children.Add(this.autoCompleteBoxElement);
this.autoCompleteBoxElement.MaxSize = new Size(this.associatedRadMultiColumnComboBox.Size.Width - this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ArrowButton.Size.Width, 0);
this.autoCompleteBoxElement.AutoCompleteDataSource = new System.Collections.Generic.List<string>(GetAutoCompleteItems());
this.autoCompleteBoxElement.Margin = new System.Windows.Forms.Padding(0);
this.autoCompleteBoxElement.Items.CollectionChanged += Items_CollectionChanged;
this.autoCompleteBoxElement.CreateTextBlock += autoCompleteBoxElement_CreateTextBlock;
this.autoCompleteBoxElement.TokenValidating += autoCompleteBoxElement_TokenValidating;
}
void associatedRadMultiColumnComboBox_ThemeNameChanged(object source, ThemeNameChangedEventArgs args)
{
this.autoCompleteBoxElement.MaxSize = new Size(this.associatedRadMultiColumnComboBox.Size.Width - this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ArrowButton.Size.Width, 0);
}
void autoCompleteBoxElement_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == System.Windows.Forms.Keys.F4)
{
associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ShowPopup();
}
if (e.KeyCode == System.Windows.Forms.Keys.Escape)
{
associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ClosePopup(RadPopupCloseReason.CloseCalled);
}
}
void associatedRadMultiColumnComboBox_DataBindingComplete(object sender, GridViewBindingCompleteEventArgs e)
{
autoCompleteBoxElement.AutoCompleteDataSource = new System.Collections.Generic.List<string>(GetAutoCompleteItems());
}
void associatedRadMultiColumnComboBox_HandleCreated(object sender, EventArgs e)
{
autoCompleteBoxElement.AutoCompleteDataSource = new System.Collections.Generic.List<string>(GetAutoCompleteItems());
}
private System.Collections.Generic.IEnumerable<string> GetAutoCompleteItems()
{
foreach (GridViewRowInfo row in this.associatedRadMultiColumnComboBox.EditorControl.Rows)
{
string value = row.Cells[this.associatedRadMultiColumnComboBox.DisplayMember].Value.ToString().Trim();
if (!rows.ContainsKey(value))
{
this.rows.Add(value, row);
}
yield return (value);
}
}
void radMultiColumnCombobox1_DropDownClosing(object sender, RadPopupClosingEventArgs args)
{
args.Cancel = (args.CloseReason == RadPopupCloseReason.Mouse &&
this.associatedRadMultiColumnComboBox.EditorControl.ElementTree.GetElementAtPoint<RadCheckBoxElement>(this.associatedRadMultiColumnComboBox.EditorControl.PointToClient(System.Windows.Forms.Cursor.Position)) != null);
this.SyncCollection();
}
void EditorControl_ViewCellFormatting(object sender, Telerik.WinControls.UI.CellFormattingEventArgs e)
{
if (e.ColumnIndex != -1 || e.CellElement.RowIndex == -1)
{
return;
}
if (e.CellElement.Children.Count == 1)
{
RadCheckBoxElement checkBoxElement = new RadCheckBoxElement();
checkBoxElement.Padding = new System.Windows.Forms.Padding(0, 3, 1, 0);
checkBoxElement.Alignment = ContentAlignment.MiddleCenter;
checkBoxElement.NotifyParentOnMouseInput = false;
e.CellElement.Children.Add(checkBoxElement);
}
RadCheckBoxElement checkBox = e.CellElement.FindDescendant<RadCheckBoxElement>();
checkBox.CheckStateChanged -= checkBox_CheckStateChanged;
checkBox.IsChecked = e.Row.Tag != null && e.Row.Tag.ToString() == Boolean.TrueString;
checkBox.CheckStateChanged += checkBox_CheckStateChanged;
}
void SyncCollection()
{
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.SuspendPropertyNotifications();
this.associatedRadMultiColumnComboBox.Text = string.Empty;
foreach (GridViewRowInfo item in this.associatedRadMultiColumnComboBox.EditorControl.Rows)
{
if (item.Tag != null && item.Tag.ToString() == Boolean.TrueString)
{
this.associatedRadMultiColumnComboBox.Text += item.Cells[this.associatedRadMultiColumnComboBox.DisplayMember].Value + "; ";
}
}
this.associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.ResumePropertyNotifications();
autoCompleteBoxElement.Items.CollectionChanged -= Items_CollectionChanged;
autoCompleteBoxElement.CreateTextBlock -= autoCompleteBoxElement_CreateTextBlock;
autoCompleteBoxElement.TokenValidating -= autoCompleteBoxElement_TokenValidating;
autoCompleteBoxElement.Text = this.associatedRadMultiColumnComboBox.Text;
autoCompleteBoxElement.TokenValidating += autoCompleteBoxElement_TokenValidating;
autoCompleteBoxElement.CreateTextBlock += autoCompleteBoxElement_CreateTextBlock;
autoCompleteBoxElement.Items.CollectionChanged += Items_CollectionChanged;
}
void autoCompleteBoxElement_TokenValidating(object sender, TokenValidatingEventArgs e)
{
if (this.rows.ContainsKey(e.Text))
{
if (this.rows[e.Text].Tag + "" == Boolean.TrueString)
{
e.IsValidToken = false;
}
}
else
{
e.IsValidToken = false;
}
}
void autoCompleteBoxElement_CreateTextBlock(object sender, CreateTextBlockEventArgs e)
{
if (this.rows.ContainsKey(e.Text) && e.TextBlock is TokenizedTextBlockElement)
{
this.rows[e.Text].Tag = Boolean.TrueString;
this.rows[e.Text].InvalidateRow();
}
}
void Items_CollectionChanged(object sender, Telerik.WinControls.Data.NotifyCollectionChangedEventArgs e)
{
if (e.Action == Telerik.WinControls.Data.NotifyCollectionChangedAction.Remove)
{
foreach (RadTokenizedTextItem item in e.NewItems)
{
if (this.rows.ContainsKey(item.Text.Trim()))
{
string itemText = item.Text.Trim();
this.rows[itemText].Tag = Boolean.FalseString;
this.rows[itemText].InvalidateRow();
}
}
}
}
void checkBox_CheckStateChanged(object sender, EventArgs e)
{
RadCheckBoxElement checkBox = sender as RadCheckBoxElement;
GridRowElement row = checkBox.FindAncestor<GridRowElement>();
row.RowInfo.Tag = checkBox.IsChecked.ToString();
}
}
<ComponentModel.ToolboxItem(False)> _
Public Class RadMultiColumnComboBoxSelectionExtender
Inherits System.ComponentModel.Component
Private m_autoCompleteBoxElement As RadAutoCompleteBoxElement
Private rows As New System.Collections.Generic.Dictionary(Of String, GridViewRowInfo)()
Private m_associatedRadMultiColumnComboBox As RadMultiColumnComboBox
Private originalSize As System.Drawing.Size = System.Drawing.Size.Empty
Public ReadOnly Property AutoCompleteBoxElement() As RadAutoCompleteBoxElement
Get
Return Me.m_autoCompleteBoxElement
End Get
End Property
''' <summary>
''' Gets the tokenized items.
''' </summary>
Public ReadOnly Property Items() As RadTokenizedTextItemCollection
Get
Return Me.m_autoCompleteBoxElement.Items
End Get
End Property
Public Property AssociatedRadMultiColumnComboBox() As RadMultiColumnComboBox
Get
Return Me.m_associatedRadMultiColumnComboBox
End Get
Set(value As RadMultiColumnComboBox)
Me.SetAssociatedRadMultiColumnComboBox(value)
End Set
End Property
Private Sub SetAssociatedRadMultiColumnComboBox(radMultiColumnComboBox As RadMultiColumnComboBox)
If radMultiColumnComboBox Is Nothing AndAlso Me.m_associatedRadMultiColumnComboBox IsNot Nothing Then
Me.SetAssociatedRadMultiColumnComboBoxCoreToNull()
End If
Me.SetAssociatedRadMultiColumnComboBoxCore(radMultiColumnComboBox)
End Sub
Private Sub SetAssociatedRadMultiColumnComboBoxCoreToNull()
RemoveHandler Me.m_associatedRadMultiColumnComboBox.HandleCreated, AddressOf associatedRadMultiColumnComboBox_HandleCreated
RemoveHandler Me.m_associatedRadMultiColumnComboBox.DataBindingComplete, AddressOf associatedRadMultiColumnComboBox_DataBindingComplete
RemoveHandler Me.m_associatedRadMultiColumnComboBox.EditorControl.ViewCellFormatting, AddressOf EditorControl_ViewCellFormatting
RemoveHandler Me.m_associatedRadMultiColumnComboBox.DropDownClosing, AddressOf radMultiColumnCombobox1_DropDownClosing
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.Visibility = ElementVisibility.Visible
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.Children(2).Children.Remove(m_autoCompleteBoxElement)
Me.m_autoCompleteBoxElement.MaxSize = New System.Drawing.Size(0, 0)
Me.m_autoCompleteBoxElement.AutoCompleteDataSource = Nothing
Me.m_associatedRadMultiColumnComboBox.AutoSize = False
Me.m_associatedRadMultiColumnComboBox.Size = Me.originalSize
For Each item As GridViewRowInfo In Me.m_associatedRadMultiColumnComboBox.EditorControl.Rows
item.Tag = Nothing
Next
RemoveHandler Me.m_autoCompleteBoxElement.Items.CollectionChanged, AddressOf Items_CollectionChanged
RemoveHandler Me.m_autoCompleteBoxElement.CreateTextBlock, AddressOf autoCompleteBoxElement_CreateTextBlock
RemoveHandler Me.m_autoCompleteBoxElement.TokenValidating, AddressOf autoCompleteBoxElement_TokenValidating
Me.m_autoCompleteBoxElement.Text = Me.m_associatedRadMultiColumnComboBox.Text
RemoveHandler Me.m_autoCompleteBoxElement.KeyDown, AddressOf autoCompleteBoxElement_KeyDown
Me.m_associatedRadMultiColumnComboBox = Nothing
Me.rows.Clear()
End Sub
Private Sub SetAssociatedRadMultiColumnComboBoxCore(radMultiColumnComboBox As RadMultiColumnComboBox)
If radMultiColumnComboBox Is Nothing Then
Return
End If
Me.originalSize = radMultiColumnComboBox.Size
Me.m_associatedRadMultiColumnComboBox = radMultiColumnComboBox
Me.m_associatedRadMultiColumnComboBox.AutoSize = True
AddHandler Me.m_associatedRadMultiColumnComboBox.ThemeNameChanged, AddressOf associatedRadMultiColumnComboBox_ThemeNameChanged
AddHandler Me.m_associatedRadMultiColumnComboBox.HandleCreated, AddressOf associatedRadMultiColumnComboBox_HandleCreated
AddHandler Me.m_associatedRadMultiColumnComboBox.DataBindingComplete, AddressOf associatedRadMultiColumnComboBox_DataBindingComplete
Me.m_associatedRadMultiColumnComboBox.DropDownStyle = RadDropDownStyle.DropDownList
AddHandler Me.m_associatedRadMultiColumnComboBox.EditorControl.ViewCellFormatting, AddressOf EditorControl_ViewCellFormatting
AddHandler Me.m_associatedRadMultiColumnComboBox.DropDownClosing, AddressOf radMultiColumnCombobox1_DropDownClosing
Me.m_autoCompleteBoxElement = New RadAutoCompleteBoxElement()
Me.m_autoCompleteBoxElement.MinSize = New System.Drawing.Size(150, 24)
Me.m_autoCompleteBoxElement.Multiline = True
Me.m_autoCompleteBoxElement.DrawBorder = False
AddHandler Me.m_autoCompleteBoxElement.KeyDown, AddressOf autoCompleteBoxElement_KeyDown
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ArrowButton.ZIndex = 1
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.Visibility = ElementVisibility.Hidden
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.Children(2).Children.Add(Me.m_autoCompleteBoxElement)
Me.m_autoCompleteBoxElement.MaxSize = New System.Drawing.Size(Me.m_associatedRadMultiColumnComboBox.Size.Width - Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ArrowButton.Size.Width, 0)
Me.m_autoCompleteBoxElement.AutoCompleteDataSource = New System.Collections.Generic.List(Of String)(GetAutoCompleteItems())
Me.m_autoCompleteBoxElement.Margin = New System.Windows.Forms.Padding(0)
AddHandler Me.m_autoCompleteBoxElement.Items.CollectionChanged, AddressOf Items_CollectionChanged
AddHandler Me.m_autoCompleteBoxElement.CreateTextBlock, AddressOf autoCompleteBoxElement_CreateTextBlock
AddHandler Me.m_autoCompleteBoxElement.TokenValidating, AddressOf autoCompleteBoxElement_TokenValidating
End Sub
Private Sub associatedRadMultiColumnComboBox_ThemeNameChanged(source As Object, args As ThemeNameChangedEventArgs)
Me.m_autoCompleteBoxElement.MaxSize = New System.Drawing.Size(Me.m_associatedRadMultiColumnComboBox.Size.Width - Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ArrowButton.Size.Width, 0)
End Sub
Private Sub autoCompleteBoxElement_KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs)
If e.KeyCode = System.Windows.Forms.Keys.F4 Then
m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ShowPopup()
End If
If e.KeyCode = System.Windows.Forms.Keys.Escape Then
m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.ClosePopup(RadPopupCloseReason.CloseCalled)
End If
End Sub
Private Sub associatedRadMultiColumnComboBox_DataBindingComplete(sender As Object, e As GridViewBindingCompleteEventArgs)
m_autoCompleteBoxElement.AutoCompleteDataSource = New System.Collections.Generic.List(Of String)(GetAutoCompleteItems())
End Sub
Private Sub associatedRadMultiColumnComboBox_HandleCreated(sender As Object, e As EventArgs)
m_autoCompleteBoxElement.AutoCompleteDataSource = New System.Collections.Generic.List(Of String)(GetAutoCompleteItems())
End Sub
Private Function GetAutoCompleteItems() As System.Collections.Generic.IEnumerable(Of String)
Dim items As New List(Of String)
For Each row As GridViewRowInfo In Me.m_associatedRadMultiColumnComboBox.EditorControl.Rows
Dim value As String = row.Cells(Me.m_associatedRadMultiColumnComboBox.DisplayMember).Value.ToString().Trim()
If Not rows.ContainsKey(value) Then
Me.rows.Add(value, row)
End If
items.Add(value)
Next
Return items
End Function
Private Sub radMultiColumnCombobox1_DropDownClosing(sender As Object, args As RadPopupClosingEventArgs)
args.Cancel = (args.CloseReason = RadPopupCloseReason.Mouse AndAlso Me.m_associatedRadMultiColumnComboBox.EditorControl.ElementTree.GetElementAtPoint(Of RadCheckBoxElement)(Me.m_associatedRadMultiColumnComboBox.EditorControl.PointToClient(System.Windows.Forms.Cursor.Position)) IsNot Nothing)
Me.SyncCollection()
End Sub
Private Sub EditorControl_ViewCellFormatting(sender As Object, e As Telerik.WinControls.UI.CellFormattingEventArgs)
If e.ColumnIndex <> -1 OrElse e.CellElement.RowIndex = -1 Then
Return
End If
If e.CellElement.Children.Count = 1 Then
Dim checkBoxElement As New RadCheckBoxElement()
checkBoxElement.Padding = New System.Windows.Forms.Padding(0, 3, 1, 0)
checkBoxElement.Alignment = ContentAlignment.MiddleCenter
checkBoxElement.NotifyParentOnMouseInput = False
e.CellElement.Children.Add(checkBoxElement)
End If
Dim checkBox As RadCheckBoxElement = e.CellElement.FindDescendant(Of RadCheckBoxElement)()
RemoveHandler checkBox.CheckStateChanged, AddressOf checkBox_CheckStateChanged
checkBox.IsChecked = e.Row.Tag IsNot Nothing AndAlso e.Row.Tag.ToString() = [Boolean].TrueString
AddHandler checkBox.CheckStateChanged, AddressOf checkBox_CheckStateChanged
End Sub
Private Sub SyncCollection()
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.SuspendPropertyNotifications()
Me.m_associatedRadMultiColumnComboBox.Text = String.Empty
For Each item As GridViewRowInfo In Me.m_associatedRadMultiColumnComboBox.EditorControl.Rows
If item.Tag IsNot Nothing AndAlso item.Tag.ToString() = [Boolean].TrueString Then
Me.m_associatedRadMultiColumnComboBox.Text += item.Cells(Me.m_associatedRadMultiColumnComboBox.DisplayMember).Value + "; "
End If
Next
Me.m_associatedRadMultiColumnComboBox.MultiColumnComboBoxElement.TextBoxElement.ResumePropertyNotifications()
RemoveHandler m_autoCompleteBoxElement.Items.CollectionChanged, AddressOf Items_CollectionChanged
RemoveHandler m_autoCompleteBoxElement.CreateTextBlock, AddressOf autoCompleteBoxElement_CreateTextBlock
RemoveHandler m_autoCompleteBoxElement.TokenValidating, AddressOf autoCompleteBoxElement_TokenValidating
m_autoCompleteBoxElement.Text = Me.m_associatedRadMultiColumnComboBox.Text
AddHandler m_autoCompleteBoxElement.TokenValidating, AddressOf autoCompleteBoxElement_TokenValidating
AddHandler m_autoCompleteBoxElement.CreateTextBlock, AddressOf autoCompleteBoxElement_CreateTextBlock
AddHandler m_autoCompleteBoxElement.Items.CollectionChanged, AddressOf Items_CollectionChanged
End Sub
Private Sub autoCompleteBoxElement_TokenValidating(sender As Object, e As TokenValidatingEventArgs)
If Me.rows.ContainsKey(e.Text) Then
If Me.rows(e.Text).Tag + "" = [Boolean].TrueString Then
e.IsValidToken = False
End If
Else
e.IsValidToken = False
End If
End Sub
Private Sub autoCompleteBoxElement_CreateTextBlock(sender As Object, e As CreateTextBlockEventArgs)
If Me.rows.ContainsKey(e.Text) AndAlso TypeOf e.TextBlock Is TokenizedTextBlockElement Then
Me.rows(e.Text).Tag = [Boolean].TrueString
Me.rows(e.Text).InvalidateRow()
End If
End Sub
Private Sub Items_CollectionChanged(sender As Object, e As Telerik.WinControls.Data.NotifyCollectionChangedEventArgs)
If e.Action = Telerik.WinControls.Data.NotifyCollectionChangedAction.Remove Then
For Each item As RadTokenizedTextItem In e.NewItems
If Me.rows.ContainsKey(item.Text.Trim()) Then
Dim itemText As String = item.Text.Trim()
Me.rows(itemText).Tag = [Boolean].FalseString
Me.rows(itemText).InvalidateRow()
End If
Next
End If
End Sub
Private Sub checkBox_CheckStateChanged(sender As Object, e As EventArgs)
Dim checkBox As RadCheckBoxElement = TryCast(sender, RadCheckBoxElement)
Dim row As GridRowElement = checkBox.FindAncestor(Of GridRowElement)()
row.RowInfo.Tag = checkBox.IsChecked.ToString()
End Sub
End Class
2. Create an instance of the above implemented extender and set its AssociatedRadMultiColumnComboBox property to the available RadMultiColumnComboBox after it is populated with data:
RadMultiColumnComboBoxSelectionExtender extender = new RadMultiColumnComboBoxSelectionExtender();
extender.AssociatedRadMultiColumnComboBox = this.radMultiColumnComboBox1;
Dim extender As New RadMultiColumnComboBoxSelectionExtender()
extender.AssociatedRadMultiColumnComboBox = Me.RadMultiColumnComboBox1
A fully functional example is available in our Demo aplication >> MultiColumnComboBox section.
Another approach is demonstrated in the How to Achieve Checked RadMultiColumnComboBox KB article.