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Search found 7 results on 1 pages for 'attachedbehaviors'.

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• Silverlight ComboBox Attached Behavior

  - by Mark Cooper

  I am trying to create an attached behavior that can be applied to a Silverlight ComboBox. My behavior is this: using System.Windows.Controls; using System.Windows; using System.Windows.Controls.Primitives; namespace AttachedBehaviours { public class ConfirmChangeBehaviour { public static bool GetConfirmChange(Selector cmb) { return (bool)cmb.GetValue(ConfirmChangeProperty); } public static void SetConfirmChange(Selector cmb, bool value) { cmb.SetValue(ConfirmChangeProperty, value); } public static readonly DependencyProperty ConfirmChangeProperty = DependencyProperty.RegisterAttached("ConfirmChange", typeof(bool), typeof(Selector), new PropertyMetadata(true, ConfirmChangeChanged)); public static void ConfirmChangeChanged(DependencyObject d, DependencyPropertyChangedEventArgs args) { Selector instance = d as Selector; if (args.NewValue is bool == false) return; if ((bool)args.NewValue) instance.SelectionChanged += OnSelectorSelectionChanged; else instance.SelectionChanged -= OnSelectorSelectionChanged; } static void OnSelectorSelectionChanged(object sender, RoutedEventArgs e) { Selector item = e.OriginalSource as Selector; MessageBox.Show("Unsaved changes. Are you sure you want to change teams?"); } } } This is used in XAML as this: <UserControl x:Class="AttachedBehaviours.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:this="clr-namespace:AttachedBehaviours" mc:Ignorable="d"> <Grid x:Name="LayoutRoot"> <StackPanel> <ComboBox ItemsSource="{Binding Teams}" this:ConfirmChangeBehaviour.ConfirmChange="true" > </ComboBox> </StackPanel> </Grid> </UserControl> I am getting an error: Unknown attribute ConfirmChangeBehaviour.ConfirmChange on element ComboBox. [Line: 13 Position: 65] Intellisense is picking up the behavior, why is this failing at runtime? Thanks, Mark EDIT: Register() changed to RegisterAttached(). Same error appears.

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• When should I use FrameworkPropertyMetadata or UIPropertyMetadata over plain PropertyMetadata?

  - by Roger Lipscombe

  When looking at sample attached properties and behaviors, I've seen a mishmash of uses of FrameworkPropertyMetadata, UIPropertyMetadata and PropertyMetadata. Since they all form an inheritance hierarchy, how do I choose which one to use?

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• Automatically calling OnDetaching() for Silverlight Behaviors

  - by Dan Auclair

  I am using several Blend behaviors and triggers on a silverlight control. I am wondering if there is any mechanism for automatically detaching or ensuring that OnDetaching() is called for a behavior or trigger when the control is no longer being used (i.e. removed from the visual tree). My problem is that there is a managed memory leak with the control because of one of the behaviors. The behavior subscribes to an event on some long-lived object in the OnAttached() override and should be unsubscribing to that event in the OnDetaching() override so that it can become a candidate for garbage collection. However, OnDetaching() never seems to be getting called when I remove the control from the visual tree... the only way I can get it to happen is by explicit detaching the behavior BEFORE removing the control and then it is properly garbage collected. Right now my only solution was to create a public method in the code-behind for the control that can go through and detach any known behaviors that would cause garbage collection problems. It would be up to the client code to know to call this before removing the control from the panel. I don't really like this approach, so I am looking for some automatic way of doing this that I am overlooking or a better suggestion. public void DetachBehaviors() { foreach (var behavior in Interaction.GetBehaviors(this.LayoutRoot)) { behavior.Detach(); } //... //continue detaching all known problematic behaviors.... }

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• WPF - attached behavior to capture MouseEnter on Image in TreeviewITem

  - by pileggi

  Hi! Could I have, please, a little code-sample of WPF "attached behavior"? I explain my problem: I've done my TreeView all with XAML but now I'd like to manage an event with code-behind. The HierarchicalDataTemplate contains an Image. I need to capture the events MouseEnter / MouseLeave on the Image. I'd like to do this with "attached behavior", but I don't know how. Thank you! Pileggi

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• WPF - Random hanging with file browser attached behaviour.

  - by Stimul8d

  Hi, I have an attached behavior defined thusly,.. public static class FileBrowserBehaviour { public static bool GetBrowsesOnClick(DependencyObject obj) { return (bool)obj.GetValue(BrowsesOnClickProperty); } public static void SetBrowsesOnClick(DependencyObject obj, bool value) { obj.SetValue(BrowsesOnClickProperty, value); } // Using a DependencyProperty as the backing store for BrowsesOnClick. This enables animation, styling, binding, etc... public static readonly DependencyProperty BrowsesOnClickProperty = DependencyProperty.RegisterAttached("BrowsesOnClick", typeof(bool), typeof(FileBrowserBehaviour), new FrameworkPropertyMetadata(false, new PropertyChangedCallback(BrowsesOnClickChanged))); public static void BrowsesOnClickChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args) { FrameworkElement fe = obj as FrameworkElement; if ((bool)args.NewValue) { fe.PreviewMouseLeftButtonDown += new MouseButtonEventHandler(OpenFileBrowser); } else { fe.PreviewMouseLeftButtonDown -= new MouseButtonEventHandler(OpenFileBrowser); } } static void OpenFileBrowser(object sender, MouseButtonEventArgs e) { var tb = sender as TextBox; if (tb.Text.Length < 1 || tb.Text=="Click to browse..") { OpenFileDialog ofd = new OpenFileDialog(); ofd.Filter = "Executables | *.exe"; if (ofd.ShowDialog() == true) { Debug.WriteLine("Setting textbox text-" + ofd.FileName); tb.Text = ofd.FileName; Debug.WriteLine("Set textbox text"); } } } } It's a nice simple attached behavior which pops open an OpenFileDialog when you click on a textbox and puts the filename in the box when you're done. It works maybe 40% of the time but the rest of the time the whole app hangs. The call stack at this point looks like this - [Managed to Native Transition] WindowsBase.dll!MS.Win32.UnsafeNativeMethods.GetMessageW(ref System.Windows.Interop.MSG msg, System.Runtime.InteropServices.HandleRef hWnd, int uMsgFilterMin, int uMsgFilterMax) + 0x15 bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.GetMessage(ref System.Windows.Interop.MSG msg, System.IntPtr hwnd, int minMessage, int maxMessage) + 0x48 bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame = {System.Windows.Threading.DispatcherFrame}) + 0x8b bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame frame) + 0x49 bytes WindowsBase.dll!System.Windows.Threading.Dispatcher.Run() + 0x4c bytes PresentationFramework.dll!System.Windows.Application.RunDispatcher(object ignore) + 0x1e bytes PresentationFramework.dll!System.Windows.Application.RunInternal(System.Windows.Window window) + 0x6f bytes PresentationFramework.dll!System.Windows.Application.Run(System.Windows.Window window) + 0x26 bytes PresentationFramework.dll!System.Windows.Application.Run() + 0x19 bytes Debugatron.exe!Debugatron.App.Main() + 0x5e bytes C# [Native to Managed Transition] [Managed to Native Transition] mscorlib.dll!System.AppDomain.nExecuteAssembly(System.Reflection.Assembly assembly, string[] args) + 0x19 bytes mscorlib.dll!System.Runtime.Hosting.ManifestRunner.Run(bool checkAptModel) + 0x6e bytes mscorlib.dll!System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly() + 0x84 bytes mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext, string[] activationCustomData) + 0x65 bytes mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext) + 0xa bytes mscorlib.dll!System.Activator.CreateInstance(System.ActivationContext activationContext) + 0x3e bytes Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone() + 0x23 bytes mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state) + 0x66 bytes mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x6f bytes mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x44 bytes Now, I've seen this kind of thing before when doing some asynchronous stuff but there's none of that going on at that point. The only thread alive is the UI thread! Also, I always get that last debug statement when it does hang. Can anyone point me in the right direction? This one's driving me crazy!

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• Why are events and commands in MVVM so unsupported by WPF / Visual Studio?

  - by Edward Tanguay

  When creating an WPF application with the MVVM pattern, it seems I have to gather the necessary tools myself to even begin the most rudimentary event handling, e.g. AttachedBehaviors I get from here DelegateCommands I get from here Now I'm looking for some way to handle the ItemSelected event in a ComboBox and am getting suggestions of tricks and workarounds to do this (using a XAML trigger or have other elements bound to the selected item, etc.). Ok, I can go down this road, but it seems to be reinventing the wheel. It would be nice to just have an ItemSelected command that I can handle in my ViewModel. Am I missing some set of standard tools or is everyone doing MVVM with WPF basically building and putting together their own collection of tools just so they can do the simplest plumbing tasks with events and commands, things that take only a couple lines in code-behind with a Click="eventHandler"?

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• Why are events and commands in MVVM so unsupported by WPF / Visual Studio?

  - by Edward Tanguay

  When creating an WPF application with the MVVM pattern, it seems I have to gather the necessary tools myself to even begin the most rudimentary event handling, e.g. AttachedBehaviors I get from here DelegateCommands I get from here Now I'm looking for some way to handle the ItemSelected event in a ComboBox and am getting suggestions of tricks and workarounds to do this (using a XAML trigger or have other elements bound to the selected item, etc.). Ok, I can go down this road, but it seems to be reinventing the wheel. It would be nice to just have an ItemSelected command that I can handle in my ViewModel. Am I missing some set of standard tools or is everyone doing MVVM with WPF basically building and putting together their own collection of tools just so they can do the simplest plumbing tasks with events and commands, things that take only a couple lines in code-behind with a Click="eventHandler"?

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