Programatically add MultipleChoiceFilter #71
Replies: 4 comments 5 replies
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Hard to say with these partial code fragments. Can you share a demo project? |
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The MultipleChoiceFilter is not the template of the column! |
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Yes, I am doing a small demo and this problem is in this row of code. |
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Where can I find your sample project? |
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I tested and problem is in behaviour from other side for SelectedItems in
DataGrid and ListBox.
if I don't use this, all works fine.
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
namespace Lesma3.AttachedBehaviors
{
public class DataGridSelecteItemsBehavior : DependencyObject
{
public static readonly DependencyProperty
IsSubscribedToSelectionChangedProperty =
DependencyProperty.RegisterAttached(
"IsSubscribedToSelectionChanged", typeof(bool),
typeof(DataGridSelecteItemsBehavior), new PropertyMetadata(default(bool)));
public static void
SetIsSubscribedToSelectionChanged(DependencyObject element, bool value) {
element.SetValue(IsSubscribedToSelectionChangedProperty, value); }
public static bool
GetIsSubscribedToSelectionChanged(DependencyObject element) { return
(bool)element.GetValue(IsSubscribedToSelectionChangedProperty); }
public static readonly DependencyProperty SelectedItemsProperty =
DependencyProperty.RegisterAttached(
"SelectedItems", typeof(IList),
typeof(DataGridSelecteItemsBehavior), new PropertyMetadata(default(IList),
OnSelectedItemsChanged));
public static void SetSelectedItems(DependencyObject element, IList
value) { element.SetValue(SelectedItemsProperty, value); }
public static IList GetSelectedItems(DependencyObject element) {
return (IList)element.GetValue(SelectedItemsProperty); }
/// <summary>
/// Attaches a list or observable collection to the grid or
listbox, syncing both lists (one way sync for simple lists).
/// </summary>
/// <param name="d">The DataGrid or ListBox</param>
/// <param name="e">The list to sync to.</param>
private static void OnSelectedItemsChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
if (!(d is ListBox || d is MultiSelector))
throw new ArgumentException("Somehow this got attached to
an object I don't support. ListBoxes and Multiselectors (DataGrid), people.
Geesh =P!");
var selector = (Selector)d;
var oldList = e.OldValue as IList;
if (oldList != null)
{
var obs = oldList as INotifyCollectionChanged;
if (obs != null)
{
obs.CollectionChanged -= OnCollectionChanged;
}
// If we're orphaned, disconnect lb/dg events.
if (e.NewValue == null)
{
selector.SelectionChanged -= OnSelectorSelectionChanged;
SetIsSubscribedToSelectionChanged(selector, false);
}
}
var newList = (IList)e.NewValue;
if (newList != null)
{
var obs = newList as INotifyCollectionChanged;
if (obs != null)
{
obs.CollectionChanged += OnCollectionChanged;
}
PushCollectionDataToSelectedItems(newList, selector);
var isSubscribed =
GetIsSubscribedToSelectionChanged(selector);
if (!isSubscribed)
{
selector.SelectionChanged += OnSelectorSelectionChanged;
SetIsSubscribedToSelectionChanged(selector, true);
}
}
}
/// <summary>
/// Initially set the selected items to the items in the newly
connected collection,
/// unless the new collection has no selected items and the
listbox/grid does, in which case
/// the flow is reversed. The data holder sets the state. If both
sides hold data, then the
/// bound IList wins and dominates the helpless wpf control.
/// </summary>
/// <param name="obs">The list to sync to</param>
/// <param name="selector">The grid or listbox</param>
private static void PushCollectionDataToSelectedItems(IList obs,
DependencyObject selector)
{
var listBox = selector as ListBox;
if (listBox != null)
{
if (obs.Count > 0)
{
listBox.SelectedItems.Clear();
foreach (var ob in obs) {
listBox.SelectedItems.Add(ob); }
}
else
{
foreach (var ob in listBox.SelectedItems) {
obs.Add(ob); }
}
return;
}
// Maybe other things will use the multiselector base... who
knows =P
var grid = selector as MultiSelector;
if (grid != null)
{
if (obs.Count > 0)
{
grid.SelectedItems.Clear();
foreach (var ob in obs) { grid.SelectedItems.Add(ob); }
}
else
{
foreach (var ob in grid.SelectedItems) { obs.Add(ob); }
}
return;
}
throw new ArgumentException("Somehow this got attached to an
object I don't support. ListBoxes and Multiselectors (DataGrid), people.
Geesh =P!");
}
/// <summary>
/// When the listbox or grid fires a selectionChanged even, we
update the attached list to
/// match it.
/// </summary>
/// <param name="sender">The listbox or grid</param>
/// <param name="e">Items added and removed.</param>
private static void OnSelectorSelectionChanged(object sender,
SelectionChangedEventArgs e)
{
var dep = (DependencyObject)sender;
var items = GetSelectedItems(dep);
var col = items as INotifyCollectionChanged;
// Remove the events so we don't fire back and forth, then
re-add them.
if (col != null) col.CollectionChanged -= OnCollectionChanged;
foreach (var oldItem in e.RemovedItems) items.Remove(oldItem);
foreach (var newItem in e.AddedItems) items.Add(newItem);
if (col != null) col.CollectionChanged += OnCollectionChanged;
}
/// <summary>
/// When the attached object implements INotifyCollectionChanged,
the attached listbox
/// or grid will have its selectedItems adjusted by this handler.
/// </summary>
/// <param name="sender">The listbox or grid</param>
/// <param name="e">The added and removed items</param>
private static void OnCollectionChanged(object sender,
NotifyCollectionChangedEventArgs e)
{
// Push the changes to the selected item.
var listbox = sender as ListBox;
if (listbox != null)
{
listbox.SelectionChanged -= OnSelectorSelectionChanged;
if (e.Action == NotifyCollectionChangedAction.Reset)
listbox.SelectedItems.Clear();
else
{
foreach (var oldItem in e.OldItems)
listbox.SelectedItems.Remove(oldItem);
foreach (var newItem in e.NewItems)
listbox.SelectedItems.Add(newItem);
}
listbox.SelectionChanged += OnSelectorSelectionChanged;
}
var grid = sender as MultiSelector;
if (grid != null)
{
grid.SelectionChanged -= OnSelectorSelectionChanged;
if (e.Action == NotifyCollectionChangedAction.Reset)
grid.SelectedItems.Clear();
else
{
foreach (var oldItem in e.OldItems)
grid.SelectedItems.Remove(oldItem);
foreach (var newItem in e.NewItems)
grid.SelectedItems.Add(newItem);
}
grid.SelectionChanged += OnSelectorSelectionChanged;
}
}
}
}
****************************
S přáním příjemného zbytku dne...
Ing. Václav Domin
http://potapeni.na.jihu.cz http://www.octopus-cb.cz
út 24. 8. 2021 v 19:00 odesílatel tom-englert ***@***.***>
napsal:
… The MultipleChoiceFilter is not the template of the column!
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Problem is on fire OnSelectorSelectionChanged event with colletion of items for MultipleChoiceFilter |
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Works great when you remove the |
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Yes, I know. I think, that problem is on file OnSelectorSelectionChanged event after collection change for MultipleChoiceFilter. Isn't redundant? |
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Selector.SelectionChanged is a routed event, so you get it from all children, too. This event should not be used for this purpose. |
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Quetion:
I create columns programatically.
Data are collection of derived types.
How add MultipleChoiceFilter?
In My Code:
GridColumns.Add(new DataGridTextColumn() { Header = txt.hdrKod, Binding = new Binding("Kod"), Width = 50, DisplayIndex = 0 });
GridColumns[0].SetTemplate(App.Current.Resources["MultipleChoiceFilter"] as System.Windows.Controls.ControlTemplate);
After bind data I got error on DatagridSelectedItemBehaviour.OnSelectorSelectionChanged on items.Add(newItem): Value is not type XXXX and cann't use on generic collection.
Where XXXX is name of class, The property "Kod" is string.
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