Within an event, I'd like to put the focus on a specific TextBox within the ListViewItem's template. The XAML looks like this:
<ListView x:Name="myList" ItemsSource="{Binding SomeList}">
<ListView.View>
<GridView>
<GridViewColumn>
<GridViewColumn.CellTemplate>
<DataTemplate>
<!-- Focus this! -->
<TextBox x:Name="myBox"/>
I've tried the following in the code behind:
(myList.FindName("myBox") as TextBox).Focus();
but I seem to have misunderstood the FindName() docs, because it returns null.
Also the ListView.Items doesn't help, because that (of course) contains my bound business objects and no ListViewItems.
Neither does myList.ItemContainerGenerator.ContainerFromItem(item), which also returns null.
To understand why ContainerFromItem didn't work for me, here some background. The event handler where I needed this functionality looks like this:
var item = new SomeListItem();
SomeList.Add(item);
ListViewItem = SomeList.ItemContainerGenerator.ContainerFromItem(item); // returns null
After the Add() the ItemContainerGenerator doesn't immediately create the container, because the CollectionChanged event could be handled on a non-UI-thread. Instead it starts an asynchronous call and waits for the UI thread to callback and execute the actual ListViewItem control generation.
To be notified when this happens, the ItemContainerGenerator exposes a StatusChanged event which is fired after all Containers are generated.
Now I have to listen to this event and decide whether the control currently want's to set focus or not.
As others have noted, The myBox TextBox can not be found by calling FindName on the ListView. However, you can get the ListViewItem that is currently selected, and use the VisualTreeHelper class to get the TextBox from the ListViewItem. To do so looks something like this:
private void myList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (myList.SelectedItem != null)
{
object o = myList.SelectedItem;
ListViewItem lvi = (ListViewItem)myList.ItemContainerGenerator.ContainerFromItem(o);
TextBox tb = FindByName("myBox", lvi) as TextBox;
if (tb != null)
tb.Dispatcher.BeginInvoke(new Func<bool>(tb.Focus));
}
}
private FrameworkElement FindByName(string name, FrameworkElement root)
{
Stack<FrameworkElement> tree = new Stack<FrameworkElement>();
tree.Push(root);
while (tree.Count > 0)
{
FrameworkElement current = tree.Pop();
if (current.Name == name)
return current;
int count = VisualTreeHelper.GetChildrenCount(current);
for (int i = 0; i < count; ++i)
{
DependencyObject child = VisualTreeHelper.GetChild(current, i);
if (child is FrameworkElement)
tree.Push((FrameworkElement)child);
}
}
return null;
}
I noticed that the question title does not directly relate to the content of the question, and neither does the accepted answer answer it. I have been able to "access the ListViewItems of a WPF ListView" by using this:
public static IEnumerable<ListViewItem> GetListViewItemsFromList(ListView lv)
{
return FindChildrenOfType<ListViewItem>(lv);
}
public static IEnumerable<T> FindChildrenOfType<T>(this DependencyObject ob)
where T : class
{
foreach (var child in GetChildren(ob))
{
T castedChild = child as T;
if (castedChild != null)
{
yield return castedChild;
}
else
{
foreach (var internalChild in FindChildrenOfType<T>(child))
{
yield return internalChild;
}
}
}
}
public static IEnumerable<DependencyObject> GetChildren(this DependencyObject ob)
{
int childCount = VisualTreeHelper.GetChildrenCount(ob);
for (int i = 0; i < childCount; i++)
{
yield return VisualTreeHelper.GetChild(ob, i);
}
}
I'm not sure how hectic the recursion gets, but it seemed to work fine in my case. And no, I have not used yield return in a recursive context before.
You can traverse up the ViewTree to find the item 'ListViewItem' record set that corresponds to the cell triggered from hit test.
Similarly, you can get the column headers from the parent view to compare and match the cell's column. You may want to bind the cell name to the column header name as your key for your comparator delegate/filter.
For example: HitResult is on TextBlock shown in green. You wish to obtain the handle to the 'ListViewItem'.
/// <summary>
/// ListView1_MouseMove
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void ListView1_MouseMove(object sender, System.Windows.Input.MouseEventArgs e) {
if (ListView1.Items.Count <= 0)
return;
// Retrieve the coordinate of the mouse position.
var pt = e.GetPosition((UIElement) sender);
// Callback to return the result of the hit test.
HitTestResultCallback myHitTestResult = result => {
var obj = result.VisualHit;
// Add additional DependancyObject types to ignore triggered by the cell's parent object container contexts here.
//-----------
if (obj is Border)
return HitTestResultBehavior.Stop;
//-----------
var parent = VisualTreeHelper.GetParent(obj) as GridViewRowPresenter;
if (parent == null)
return HitTestResultBehavior.Stop;
var headers = parent.Columns.ToDictionary(column => column.Header.ToString());
// Traverse up the VisualTree and find the record set.
DependencyObject d = parent;
do {
d = VisualTreeHelper.GetParent(d);
} while (d != null && !(d is ListViewItem));
// Reached the end of element set as root's scope.
if (d == null)
return HitTestResultBehavior.Stop;
var item = d as ListViewItem;
var index = ListView1.ItemContainerGenerator.IndexFromContainer(item);
Debug.WriteLine(index);
lblCursorPosition.Text = $"Over {item.Name} at ({index})";
// Set the behavior to return visuals at all z-order levels.
return HitTestResultBehavior.Continue;
};
// Set up a callback to receive the hit test result enumeration.
VisualTreeHelper.HitTest((Visual)sender, null, myHitTestResult, new PointHitTestParameters(pt));
}
We use a similar technique with WPF's new datagrid:
Private Sub SelectAllText(ByVal cell As DataGridCell)
If cell IsNot Nothing Then
Dim txtBox As TextBox= GetVisualChild(Of TextBox)(cell)
If txtBox IsNot Nothing Then
txtBox.Focus()
txtBox.SelectAll()
End If
End If
End Sub
Public Shared Function GetVisualChild(Of T As {Visual, New})(ByVal parent As Visual) As T
Dim child As T = Nothing
Dim numVisuals As Integer = VisualTreeHelper.GetChildrenCount(parent)
For i As Integer = 0 To numVisuals - 1
Dim v As Visual = TryCast(VisualTreeHelper.GetChild(parent, i), Visual)
If v IsNot Nothing Then
child = TryCast(v, T)
If child Is Nothing Then
child = GetVisualChild(Of T)(v)
Else
Exit For
End If
End If
Next
Return child
End Function
The technique should be fairly applicable for you, just pass your listviewitem once it's generated.
Or it can be simply done by
private void yourtextboxinWPFGrid_LostFocus(object sender, RoutedEventArgs e)
{
//textbox can be catched like this.
var textBox = ((TextBox)sender);
EmailValidation(textBox.Text);
}
Related
I need to get access to the binding expression of the DataGrid cell in a DataGridTextColumn. For example:
<DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
I managed to get the TextBlock associated with the cell:
var cell = dataGrid.GetCellCtrl<TextBlock>(dataGrid.CurrentCell);
And cell seems to be correct. I can call
cell.SetValue(TextBlock.TextProperty, value);
To update the cell text. It seems to be working on the grid (number updated). However, as I realize after a while, the source doesn't get updated. It didn't help even if I turn UpdateSourceTrigger to PropertyChange. Then, I thought I need to get the binding expression and call UpdateSource explicitly.
var bindingExpr = cell.GetBindingExpression(TextBlock.TextProperty);
but bindingExpr is always null. Why?
EDIT:
The original problem I had was that I can get to the binding TextBlock for the cell, and set the TextBlock.TextProperty. However, the source doesn't get updated. This is something I'm trying to resolve this problem.
The TextBox in the DataGridTextColumn will not have a binding expression the column itself has the binding.
DataGridTextColumn is derived from DataGridBoundColumn which uses a BindingBase property not TextBlock.TextProperty, However the Binding property is not a DependancyProperty so you will have to access using normal public properties.
So you will have to do a bit of casting as the Binding property in DataGridTextColumn is type BindingBase.
Something like this should work (untested)
var binding = (yourGrid.Columns[0] as DataGridBoundColumn).Binding as Binding;
You need to find the TextBlock:
var textBlock = cell.FindVisualChild<TextBlock>();
BindingExpression bindingExpression = textBlock.GetBindingExpression(
TextBlock.TextProperty);
Code for FindVisualChild():
public static class DependencyObjectExtensions
{
[NotNull]
public static IEnumerable<T> FindVisualChildren<T>([NotNull] this DependencyObject dependencyObject)
where T : DependencyObject
{
if (dependencyObject == null) throw new ArgumentNullException(nameof(dependencyObject));
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(dependencyObject); i++)
{
DependencyObject child = VisualTreeHelper.GetChild(dependencyObject, i);
if (child is T o)
yield return o;
foreach (T childOfChild in FindVisualChildren<T>(child))
yield return childOfChild;
}
}
public static childItem FindVisualChild<childItem>([NotNull] this DependencyObject dependencyObject)
where childItem : DependencyObject
{
if (dependencyObject == null) throw new ArgumentNullException(nameof(dependencyObject));
foreach (childItem child in FindVisualChildren<childItem>(dependencyObject))
return child;
return null;
}
}
TextBox t = e.EditingElement as TextBox;
string b= t.GetBindingExpression(TextBox.TextProperty).ResolvedSourcePropertyName;
I need to add some decoration to the contents of a WPF TextBox control. That works fine basically, I can get the position of specified character indices and layout my other elements accordingly. But it all breaks when the TextBox is scrolled. My layout positions don't match with the displayed text anymore because it has moved elsewhere.
Now I'm pretty surprised that the TextBox class doesn't provide any information about its scrolling state, nor any events when the scrolling has changed. What can I do now?
I used Snoop to find out whether there is some scrolling sub-element that I could ask, but the ScrollContentPresenter also doesn't have any scrolling information available. I'd really like to put my decoration elements right into the scrolled area so that the scrolling can affect them, too, but there can only be a single content control and that's one of the TextBox internals already.
I'm not sure how to capture an event when the textbox has been scrolled (probably use narohi's answer for that), but there is a simple way to see what the current scroll position is:
// Gets or sets the vertical scroll position.
textBox.VerticalOffset
(From http://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.textboxbase.verticaloffset(v=vs.100).aspx)
I'm using it to see if the textbox is scrolled to the end, like this:
public static bool IsScrolledToEnd(this TextBox textBox)
{
return textBox.VerticalOffset + textBox.ViewportHeight == textBox.ExtentHeight;
}
You can get the ScrollViewer with this method by passing in your textbox as the argument and the type ScrollView. Then you may subscribe to the ScrollChanged event.
public static T FindDescendant<T>(DependencyObject obj) where T : DependencyObject
{
if (obj == null) return default(T);
int numberChildren = VisualTreeHelper.GetChildrenCount(obj);
if (numberChildren == 0) return default(T);
for (int i = 0; i < numberChildren; i++)
{
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
if (child is T)
{
return (T)(object)child;
}
}
for (int i = 0; i < numberChildren; i++)
{
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
var potentialMatch = FindDescendant<T>(child);
if (potentialMatch != default(T))
{
return potentialMatch;
}
}
return default(T);
}
Example:
public MainWindow()
{
InitializeComponent();
Loaded += new RoutedEventHandler(MainWindow_Loaded);
}
void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
ScrollViewer s = FindDescendant<ScrollViewer>(txtYourTextBox);
s.ScrollChanged += new ScrollChangedEventHandler(s_ScrollChanged);
}
void s_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
// check event args for information needed
}
Ok... this has me stumped. I've overridden OnContentTemplateChanged in my UserControl subclass. I'm checking that the value passed in for newContentTemplate does in fact equal this.ContentTemplate (it does) yet when I call this...
var textBox = this.ContentTemplate.FindName("EditTextBox", this);
...it throws the following exception...
"This operation is valid only on elements that have this template applied."
Per a commenter in another related question, he said you're supposed to pass in the content presenter for the control, not the control itself, so I then tried this...
var cp = FindVisualChild<ContentPresenter>(this);
var textBox = this.ContentTemplate.FindName("EditTextBox", cp);
...where FindVisualChild is just a helper function used in MSDN's example (see below) to find the associated content presenter. While cp is found, it too throws the same error. I'm stumped!!
Here's the helper function for reference...
private TChildItem FindVisualChild<TChildItem>(DependencyObject obj)
where TChildItem : DependencyObject {
for(int i = 0 ; i < VisualTreeHelper.GetChildrenCount(obj) ; i++) {
var child = VisualTreeHelper.GetChild(obj, i);
if(child is TChildItem typedChild) {
return typedChild;
}
else {
var childOfChild = FindVisualChild<TChildItem>(child);
if(childOfChild != null)
return childOfChild;
}
}
return null;
}
Explicitly applying the template before calling the FindName method will prevent this error.
this.ApplyTemplate();
As John pointed out, the OnContentTemplateChanged is being fired before it is actually applied to the underlying ContentPresenter. So you'd need to delay your call to FindName until it is applied. Something like:
protected override void OnContentTemplateChanged(DataTemplate oldContentTemplate, DataTemplate newContentTemplate) {
base.OnContentTemplateChanged(oldContentTemplate, newContentTemplate);
this.Dispatcher.BeginInvoke((Action)(() => {
var cp = FindVisualChild<ContentPresenter>(this);
var textBox = this.ContentTemplate.FindName("EditTextBox", cp) as TextBox;
textBox.Text = "Found in OnContentTemplateChanged";
}), DispatcherPriority.DataBind);
}
Alternatively, you may be able to attach a handler to the LayoutUpdated event of the UserControl, but this may fire more often than you want. This would also handle the cases of implicit DataTemplates though.
Something like this:
public UserControl1() {
InitializeComponent();
this.LayoutUpdated += new EventHandler(UserControl1_LayoutUpdated);
}
void UserControl1_LayoutUpdated(object sender, EventArgs e) {
var cp = FindVisualChild<ContentPresenter>(this);
var textBox = this.ContentTemplate.FindName("EditTextBox", cp) as TextBox;
textBox.Text = "Found in UserControl1_LayoutUpdated";
}
The ContentTemplate isn't applied to the ContentPresenter until after that event. While the ContentTemplate property is set on the control at that point, it hasn't been pushed down to bindings internal to the ControlTemplate, like the ContentPresenter's ContentTemplate.
What are you ultimately trying to do with the ContentTemplate? There might be a better overall approach to reach your end goal.
I am trying to create a Blend behavior related to ComboBoxes. In order to get the effect I want, the ItemsPanel of the ComboBox has to have a certain element added to it. I don't want to do this in every ComboBox that uses the behavior, so I want the Behavior to be able to inject the ItemsPanelTemplate programmatically. However, I can't seem to find a way to do this. ItemsPanelTemplate does not seem to have a property/method that lets me set the visual tree. WPF ItemsPanelTemplate has the VisualTree but Silverlight does not.
Basically, what is the programmatic equivalent of this XAML?
<ComboBox>
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel/>
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
</ComboBox>
Edit:
Okay apparently that is not an easy question, so I started a bounty and I'm going to give some more background in case there is another way to go about this. I want to provide keyboard support for the Silverlight ComoboBox. Out of the box it only supports the up and down arrows but I also want it to work so that when the user hits a letter, the ComboBox jumps to the first item of that letter, similar to how ComboBoxes work in a browser or Windows app.
I found this blog post, which got me half way. Adapting that behavior code, the ComboBox will change selection based on letter input. However, it does not work when the ComboBox is opened. The reason for this, according to this blog post is that when the ComboBox is opened, you are now interacting with its ItemsPanel and not the ComboBox itself. So according to that post I actually need to add a StackPanel to the ItemsPanelTemplate and subscribe to the StackPanel's KeyDown event, in order to take action when the ComboBox is opened.
So that is what prompted my question of how to get a StackPanel into the ItemsPanelTemplate of a ComboBox, from a behavior. If that is not possible, are there alternative ways of getting this to work? Yes, I know I could go to each ComboBox in the application and add a StackPanel and the event. But I want to do this through a behavior so that I don't have to modify every ComboBox in the app, and so I can reuse this logic across applications.
AnthonyWJones' answer below using XamlReader gets me part way, in that I can create the StackPanel and get it into the template. However, I need to be able to get at that SP programmatically in order to subscribe to the event.
This should work. I've shown how you can change the orientation below. You can add additional SetValue calls to modify other properties.
cb.ItemsPanel = new ItemsPanelTemplate();
var stackPanelFactory = new FrameworkElementFactory(typeof (StackPanel));
// Modify it like this:
stackPanelFactory.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal);
// Set the root of the template to the stack panel factory:
cb.ItemsPanel.VisualTree = stackPanelFactory;
You can find more detailed information in this article: http://www.codeproject.com/KB/WPF/codeVsXAML.aspx
What you actually want to build programmatically is this:-
<ItemsPanelTemplate>
<StackPanel />
</ItemsPanelTemplate>
Your behaviour will then assign this to the ItemsPanel property of the ComboBox it is attached to. Currently your behaviour is pure code but there is no way to create the above purely in code.
Since this is such a small piece for of Xaml the easiest approach is to use the XamlReader:-
ItemsPanelTemplate itemsPanelTemplate = XamlReader.Load("<ItemsPanelTemplate><StackPanel /></ItemsPanelTemplate>");
I think, best way for you - extend combobox functionality not via behavior but using inheritance.
So, you can create own control MyComboBox:ComboBox. Create style for it - get default ComboBox Style
here
And write instead (look for ScrollViewer by name):
< ScrollViewer x:Name="ScrollViewer" BorderThickness="0" Padding="1" >
< ItemsPresenter />
< /ScrollViewer >
this
< ScrollViewer x:Name="ScrollViewer" BorderThickness="0" Padding="1" >
< StackPanel x:Name="StackPanel" >
< ItemsPresenter />
< /StackPanel >
< /ScrollViewer >
This StackPanel you can get in code:
public class MyComboBox: ComboBox{
public CM()
{
DefaultStyleKey = typeof (MyComboBox);
}
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
StackPanel stackPanel = (StackPanel)GetTemplateChild("StackPanel");
stackPanel.KeyUp += (s, e) => { /*do something*/ };
}
}
Inheritance is more powerful. It's allow work with template elements.
If you decided to inject ItemsPanel, you must understand that:
1)it's impossible from code with keeping reference on injected panel.
2)to get reference to injected panel, this panel must registered itself in some storage, e.g.
< ComboBox>
< ComboBox.ItemsPanel>
< ItemsPanelTemplate>
< StackPanel>
< i:Interaction.EventTriggers>
< i:EventTrigger EventName="Loaded">
< RegisterMyInstanceInAccessibleFromCodePlaceAction/>
< /i:EventTrigger>
< /i:Interaction.EventTriggers>
< /StackPanel>
< /ItemsPanelTemplate>
< /ComboBox.ItemsPanel>
< /ComboBox>
Good luck!
I found your post while trying to set the ItemsPanel from code so that I can implement a VirtualizingStackPanel. When there are hundreds of items in my list, performance sucks. Anyway .. here's how I did it.
1) Custom control
2) Custom Behavior
-- you could also just apply this behavior to the normal ComboBox - either at each instance, or through a style.
-- you might also expose the timeout value so that can be overridden in xaml ..
-- also, it seems this doesn't work when the dropdown itself is open. not sure why exactly .. never looked into it
1..
public class KeyPressSelectionComboBox : ComboBox
{
private BindingExpression _bindingExpression;
public KeyPressSelectionComboBox()
: base()
{
Interaction.GetBehaviors(this).Add(new KeyPressSelectionBehavior());
Height = 22;
this.SelectionChanged += new SelectionChangedEventHandler(KeyPressSelectionComboBox_SelectionChanged);
}
void KeyPressSelectionComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (_bindingExpression == null)
{
_bindingExpression = this.GetBindingExpression(ComboBox.SelectedValueProperty);
}
else
{
if (this.GetBindingExpression(ComboBox.SelectedValueProperty) == null)
{
this.SetBinding(ComboBox.SelectedValueProperty, _bindingExpression.ParentBinding);
}
}
}
}
2...
/// <summary>
/// This behavior can be attached to a ListBox or ComboBox to
/// add keyboard selection
/// </summary>
public class KeyPressSelectionBehavior : Behavior<Selector>
{
private string keyDownHistory = string.Empty;
private double _keyDownTimeout = 2500;
private DateTime _lastKeyDownTime;
private DateTime LastKeyDownTime
{
get
{
if (this._lastKeyDownTime == null)
this._lastKeyDownTime = DateTime.Now;
return this._lastKeyDownTime;
}
set { _lastKeyDownTime = value; }
}
/// <summary>
/// Gets or sets the Path used to select the text
/// </summary>
public string SelectionMemberPath { get; set; }
/// <summary>
/// Gets or sets the Timeout (ms) used to reset the KeyDownHistory item search string
/// </summary>
public double KeyDownTimeout
{
get { return _keyDownTimeout; }
set { _keyDownTimeout = value; }
}
public KeyPressSelectionBehavior() { }
/// <summary>
/// Attaches to the specified object: subscribe on KeyDown event
/// </summary>
protected override void OnAttached()
{
base.OnAttached();
this.AssociatedObject.KeyDown += DoKeyDown;
}
void DoKeyDown(object sender, KeyEventArgs e)
{
// Create a list of strings and indexes
int index = 0;
IEnumerable<Item> list = null;
var path = SelectionMemberPath ??
this.AssociatedObject.DisplayMemberPath;
var evaluator = new BindingEvaluator();
if (path != null)
{
list = this.AssociatedObject.Items.OfType<object>()
.Select(item =>
{
// retrieve the value using the supplied Path
var binding = new Binding();
binding.Path = new PropertyPath(path);
binding.Source = item;
BindingOperations.SetBinding(evaluator,
BindingEvaluator.TargetProperty, binding);
var value = evaluator.Target;
return new Item
{
Index = index++,
Text = Convert.ToString(value)
};
});
}
else
{
list = this.AssociatedObject.Items.OfType<ListBoxItem>()
.Select(item => new Item
{
Index = index++,
Text = Convert.ToString(item.Content)
});
}
// Sort the list starting at next selectedIndex to the end and
// then from the beginning
list = list.OrderBy(item => item.Index <=
this.AssociatedObject.SelectedIndex ?
item.Index + this.AssociatedObject.Items.Count : item.Index);
// calculate how long has passed since the user typed a letter
var elapsedTime = DateTime.Now - this.LastKeyDownTime;
if (elapsedTime.TotalMilliseconds <= this.KeyDownTimeout)
{ /* if it's less than the timeout, add to the search string */
this.keyDownHistory += GetKeyValue(e);
}
else
{ /* otherwise replace it */
this.keyDownHistory = GetKeyValue(e);
}
// Find first starting with the search string
var searchText = this.keyDownHistory;
var first = list.FirstOrDefault(item =>
item.Text.StartsWith(searchText, StringComparison.InvariantCultureIgnoreCase));
if (first != null)
{ /* found */
this.AssociatedObject.SelectedIndex = first.Index;
}
else
{ /* not found - so reset the KeyDownHistory */
this.keyDownHistory = string.Empty;
}
// reset the last time a key was pressed
this.LastKeyDownTime = DateTime.Now;
}
/// <summary>
/// Gets the value of the pressed key,
/// specifically converting number keys from their "Dx" value to their expected "x" value
/// </summary>
/// <param name="e"></param>
/// <returns></returns>
private static string GetKeyValue(KeyEventArgs e)
{
string rValue = string.Empty;
switch (e.Key)
{
default:
rValue = e.Key.ToString();
break;
case Key.D0:
case Key.NumPad0:
rValue = (0).ToString();
break;
case Key.D1:
case Key.NumPad1:
rValue = (1).ToString();
break;
case Key.D2:
case Key.NumPad2:
rValue = (2).ToString();
break;
case Key.D3:
case Key.NumPad3:
rValue = (3).ToString();
break;
case Key.D4:
case Key.NumPad4:
rValue = (4).ToString();
break;
case Key.D5:
case Key.NumPad5:
rValue = (5).ToString();
break;
case Key.D6:
case Key.NumPad6:
rValue = (6).ToString();
break;
case Key.D7:
case Key.NumPad7:
rValue = (7).ToString();
break;
case Key.D8:
case Key.NumPad8:
rValue = (8).ToString();
break;
case Key.D9:
case Key.NumPad9:
rValue = (9).ToString();
break;
}
return rValue;
}
/// <summary>
/// Helper class
/// </summary>
private class Item
{
public int Index;
public string Text;
}
/// <summary>
/// Helper class used for property path value retrieval
/// </summary>
private class BindingEvaluator : FrameworkElement
{
public static readonly DependencyProperty TargetProperty =
DependencyProperty.Register(
"Target",
typeof(object),
typeof(BindingEvaluator), null);
public object Target
{
get { return GetValue(TargetProperty); }
set { SetValue(TargetProperty, value); }
}
}
}
I have a ListBox with dates.
Each ListBoxItem (date) have another ListBox with that date's events.
When I select an event it gets highlighted (SelectedIndex/SelectedItem) and I navigate to another Pivot. This works fine.
My problem is that every ListBox has it's own SelectedItem. I want to clear the SelectedItem from each ListBox, but I cannot get it to work!
Here's my try:
//Store a reference to the latest selected ListBox
public ListBox SelectedListBox { get; set; }
private void SelectionChangedHandler(object sender, SelectionChangedEventArgs e)
{
ListBox lstBox = ((ListBox)sender);
//This row breaks the SECOND time!!
var episode = (Episode)lstBox.SelectedItem;
episodeShowName.Text = episode.Show; //Do some code
episodeTitle.Text = episode.Name; //Do some code
episodeNumber.Text = episode.Number; //Do some code
episodeSummary.Text = episode.Summary; //Do some code
resetListBox(lstBox); //Do the reset !
pivot1.SelectedIndex = 1;
}
private void resetListBox(ListBox lstBox)
{
if (SelectedListBox != null)
SelectedListBox.SelectedIndex = -1;
//If I remove this line, the code doesn't break anymore
SelectedListBox = lstBox; //Set the current ListBox as reference
}
var episode is null the second time. How come?
I found the problem!
private void resetListBox(ListBox lstBox)
{
if (SelectedListBox != null)
SelectedListBox.SelectedIndex = -1;
//If I remove this line, the code doesn't break anymore
SelectedListBox = lstBox; //Set the current ListBox as reference
}
When I set the previous selected ListBox's SelectedIndex to -1, the SelectionChangedHandler event gets triggered again (of course) and screws up ! :D
Easy fix:
private void SelectionChangedHandler(object sender, SelectionChangedEventArgs e)
{
ListBox lstBox = ((ListBox)sender);
if (lstBox.SelectedIndex < 0)
return;