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Allow for waiting for DialogHost animations. #4083

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8 changes: 6 additions & 2 deletions src/MainDemo.Wpf/Dialogs.xaml.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -42,8 +42,12 @@ private void Sample1_DialogHost_OnDialogClosed(object sender, DialogClosedEventA
}

// Used for DialogHost.DialogClosingAttached
private void Sample2_DialogHost_OnDialogClosing(object sender, DialogClosingEventArgs eventArgs)
=> Debug.WriteLine($"SAMPLE 2: Closing dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
private async void Sample2_DialogHost_OnDialogClosing(object sender, DialogClosingEventArgs eventArgs)
{
Debug.WriteLine($"{DateTime.Now.TimeOfDay} SAMPLE 2: Closing dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
await eventArgs.Session.DialogHost.WaitForClosed();
Debug.WriteLine($"{DateTime.Now.TimeOfDay} SAMPLE 2: Closed dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
}

private void Sample2_DialogHost_OnDialogClosed(object sender, DialogClosedEventArgs eventArgs)
=> Debug.WriteLine($"SAMPLE 2: Closed dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
Expand Down
9 changes: 7 additions & 2 deletions src/MaterialDesign3.Demo.Wpf/Dialogs.xaml.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using System.Diagnostics;
using System.Threading;
using MaterialDesign3Demo.Domain;
using MaterialDesignThemes.Wpf;

Expand Down Expand Up @@ -27,8 +28,12 @@ private void Sample1_DialogHost_OnDialogClosing(object sender, DialogClosingEven
}

// Used for DialogHost.DialogClosingAttached
private void Sample2_DialogHost_OnDialogClosing(object sender, DialogClosingEventArgs eventArgs)
=> Debug.WriteLine($"SAMPLE 2: Closing dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
private async void Sample2_DialogHost_OnDialogClosing(object sender, DialogClosingEventArgs eventArgs)
{
Debug.WriteLine($"{DateTime.Now.TimeOfDay} SAMPLE 2: Closing dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
await eventArgs.Session.DialogHost.WaitForClosed();
Debug.WriteLine($"{DateTime.Now.TimeOfDay} SAMPLE 2: Closed dialog with parameter: {eventArgs.Parameter ?? string.Empty}");
}

private void Sample5_DialogHost_OnDialogClosing(object sender, DialogClosingEventArgs eventArgs)
{
Expand Down
40 changes: 32 additions & 8 deletions src/MaterialDesignThemes.Wpf/DialogHost.cs
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Original file line number Diff line number Diff line change
@@ -1,9 +1,12 @@
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Security;
using System.Threading;
using System.Windows.Data;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Threading;
using MaterialDesignThemes.Wpf.Internal;

namespace MaterialDesignThemes.Wpf;

Expand Down Expand Up @@ -31,13 +34,18 @@ public enum DialogHostOpenDialogCommandDataContextSource
[TemplatePart(Name = PopupPartName, Type = typeof(Popup))]
[TemplatePart(Name = PopupPartName, Type = typeof(ContentControl))]
[TemplatePart(Name = ContentCoverGridName, Type = typeof(Grid))]
[TemplateVisualState(GroupName = "PopupStates", Name = OpenStateName)]
[TemplateVisualState(GroupName = "PopupStates", Name = ClosedStateName)]
[TemplatePart(Name = RootContentPartName, Type = typeof(FrameworkElement))]
[TemplateVisualState(GroupName = VisualStateGroupName, Name = OpenStateName)]
[TemplateVisualState(GroupName = VisualStateGroupName, Name = ClosedStateName)]
public class DialogHost : ContentControl
{
public const string VisualStateGroupName = "PopupStates";

public const string PopupPartName = "PART_Popup";
public const string PopupContentPartName = "PART_PopupContentElement";
public const string ContentCoverGridName = "PART_ContentCoverGrid";
public const string RootContentPartName = "PART_DialogHostRoot";

public const string OpenStateName = "Open";
public const string ClosedStateName = "Closed";

Expand All @@ -57,6 +65,9 @@ public class DialogHost : ContentControl
private DialogClosedEventHandler? _asyncShowClosedEventHandler;
private TaskCompletionSource<object?>? _dialogTaskCompletionSource;

private VisualStateMonitor? _visualStateMonitor;


private Popup? _popup;
private ContentControl? _popupContentControl;
private Grid? _contentCoverGrid;
Expand Down Expand Up @@ -395,7 +406,8 @@ private static void IsOpenPropertyChangedCallback(DependencyObject dependencyObj

//https://github.com/MaterialDesignInXAML/MaterialDesignInXamlToolkit/issues/187
//totally not happy about this, but on immediate validation we can get some weird looking stuff...give WPF a kick to refresh...
Task.Delay(300).ContinueWith(t => dialogHost.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() => {
Task.Delay(300).ContinueWith(t => dialogHost.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
{
CommandManager.InvalidateRequerySuggested();
//Delay focusing the popup until after the animation has some time, Issue #2912
UIElement? child = dialogHost.FocusPopup();
Expand Down Expand Up @@ -628,9 +640,26 @@ public override void OnApplyTemplate()

VisualStateManager.GoToState(this, GetStateName(), false);

if (GetTemplateChild(RootContentPartName) is FrameworkElement root &&
VisualStateManager.GetVisualStateGroups(root) is [VisualStateGroup stateGroup, ..])
{
var stateNames = stateGroup.States.OfType<VisualStateGroup>().Select(x => x.Name).ToList();
if (stateNames.Contains(OpenStateName) && stateNames.Contains(ClosedStateName))
{
_visualStateMonitor = new(stateGroup);
}
}
base.OnApplyTemplate();
}

public Task WaitForOpened(CancellationToken cancellationToken = default)
=> _visualStateMonitor?.WaitForState(OpenStateName, cancellationToken)

@nicolaihenriksen nicolaihenriksen Aug 22, 2026

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Regarding whether cancellationToken should be required: How about setting a reasonable self-cancelling token (say 5 seconds) if one is not supplied by the caller? I guess what you're trying to avoid by making it mandatory is the infinite hang waiting for a state change that never occurs? A reasonable default token would do that too I guess.

My assumption here is that the caller would only call these methods right before opening/closing the DialogHost and therefore the timeout should just be slightly longer than the duration of the animation. I hope my assumption is correct.

?? throw new InvalidOperationException("Unable to locate visual states for the DialogHost, cannot wait for state transitions");

public Task WaitForClosed(CancellationToken cancellationToken = default)
=> _visualStateMonitor?.WaitForState(ClosedStateName, cancellationToken)
?? throw new InvalidOperationException("Unable to locate visual states for the DialogHost, cannot wait for state transitions");

#region restore focus properties

public static readonly DependencyProperty RestoreFocusElementProperty = DependencyProperty.RegisterAttached(
Expand Down Expand Up @@ -967,11 +996,6 @@ private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
}
}

private void OnPreviewGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{

}

[SecurityCritical]
[DllImport("user32.dll", EntryPoint = "SetFocus", SetLastError = true)]
private static extern IntPtr SetFocus(IntPtr hWnd);
Expand Down
24 changes: 12 additions & 12 deletions src/MaterialDesignThemes.Wpf/DialogSession.cs
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Expand Up @@ -7,16 +7,16 @@ namespace MaterialDesignThemes.Wpf;
/// </summary>
public class DialogSession
{
private readonly DialogHost _owner;

internal DialogSession(DialogHost owner)
=> _owner = owner ?? throw new ArgumentNullException(nameof(owner));
=> DialogHost = owner ?? throw new ArgumentNullException(nameof(owner));

public DialogHost DialogHost { get; }

/// <summary>
/// Indicates if the dialog session has ended. Once ended no further method calls will be permitted.
/// Indicates if the dialog session has ended. Once ended no further method calls will be permitted.
/// </summary>
/// <remarks>
/// Client code cannot set this directly, this is internally managed. To end the dialog session use <see cref="Close()"/>.
/// Client code cannot set this directly, this is internally managed. To end the dialog session use <see cref="Close()"/>.
/// </remarks>
public bool IsEnded { get; internal set; }

Expand All @@ -28,19 +28,19 @@ internal DialogSession(DialogHost owner)
/// <summary>
/// Gets the <see cref="DialogHost.DialogContent"/> which is currently displayed, so this could be a view model or a UI element.
/// </summary>
public object? Content => _owner.DialogContent;
public object? Content => DialogHost.DialogContent;

/// <summary>
/// Update the current content in the dialog.
/// </summary>
/// <param name="content"></param>
public void UpdateContent(object? content)
{
_owner.AssertTargetableContent();
_owner.DialogContent = content;
_owner.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
DialogHost.AssertTargetableContent();
DialogHost.DialogContent = content;
DialogHost.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
{
_owner.FocusPopup();
DialogHost.FocusPopup();
}));
}

Expand All @@ -52,7 +52,7 @@ public void Close()
{
if (IsEnded) throw new InvalidOperationException("Dialog session has ended.");

_owner.InternalClose(null);
DialogHost.InternalClose(null);
}

/// <summary>
Expand All @@ -64,6 +64,6 @@ public void Close(object? parameter)
{
if (IsEnded) throw new InvalidOperationException("Dialog session has ended.");

_owner.InternalClose(parameter);
DialogHost.InternalClose(parameter);
}
}
45 changes: 45 additions & 0 deletions src/MaterialDesignThemes.Wpf/Internal/VisualStateMonitor.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
using System.Threading;

namespace MaterialDesignThemes.Wpf.Internal;

internal sealed class VisualStateMonitor
{
private readonly VisualStateGroup _visualStateGroup;

public VisualStateMonitor(VisualStateGroup visualStateGroup)
{
_visualStateGroup = visualStateGroup ??
throw new ArgumentNullException(nameof(visualStateGroup));
}

public Task WaitForState(string state, CancellationToken cancellationToken)
{
string currentState = _visualStateGroup.CurrentState.Name;
if (currentState == state) return Task.CompletedTask;

TaskCompletionSource<string> tcs = new();
cancellationToken.Register(() => tcs.TrySetCanceled());

EventHandler<VisualStateChangedEventArgs> stateChanged = null!;
stateChanged = (sender, e) =>
{
if (e.NewState.Name == state)
{
_visualStateGroup.CurrentStateChanged -= stateChanged;
tcs.TrySetResult(state);
}
};

_visualStateGroup.CurrentStateChanged += stateChanged;

currentState = _visualStateGroup.CurrentState.Name;
if (currentState == state)
{
_visualStateGroup.CurrentStateChanged -= stateChanged;

return Task.CompletedTask;
}
Comment on lines +35 to +41

@nicolaihenriksen nicolaihenriksen Aug 22, 2026

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Don't you already have this guard in line 17-18? Is there a scenario where the current state can change between line 18 and here?


return tcs.Task;
}
}
26 changes: 13 additions & 13 deletions src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.DialogHost.xaml
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Original file line number Diff line number Diff line change
Expand Up @@ -25,11 +25,11 @@
<ControlTemplate.Resources>
<converters:FirstNonNullConverter x:Key="FirstNonNullConverter" />
</ControlTemplate.Resources>
<Grid x:Name="DialogHostRoot" Focusable="False">
<Grid x:Name="PART_DialogHostRoot" Focusable="False">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="PopupStates">
<VisualStateGroup Name="{x:Static wpf:DialogHost.VisualStateGroupName}">
<VisualStateGroup.Transitions>
<VisualTransition From="Closed" To="Open">
<VisualTransition From="{x:Static wpf:DialogHost.ClosedStateName}" To="{x:Static wpf:DialogHost.OpenStateName}">
<Storyboard>
<BooleanAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup" Storyboard.TargetProperty="IsOpen">
<DiscreteBooleanKeyFrame KeyTime="0" Value="True" />
Expand Down Expand Up @@ -68,7 +68,7 @@
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualTransition>
<VisualTransition From="Open" To="Closed">
<VisualTransition From="{x:Static wpf:DialogHost.OpenStateName}" To="{x:Static wpf:DialogHost.ClosedStateName}">
<Storyboard>
<BooleanAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup" Storyboard.TargetProperty="IsOpen">
<DiscreteBooleanKeyFrame KeyTime="0:0:0.3" Value="False" />
Expand Down Expand Up @@ -111,7 +111,7 @@
</Storyboard>
</VisualTransition>
</VisualStateGroup.Transitions>
<VisualState x:Name="Open">
<VisualState Name="{x:Static wpf:DialogHost.OpenStateName}">
<Storyboard>
<BooleanAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup"
Storyboard.TargetProperty="IsOpen"
Expand All @@ -136,7 +136,7 @@
Duration="0" />
</Storyboard>
</VisualState>
<VisualState x:Name="Closed">
<VisualState Name="{x:Static wpf:DialogHost.ClosedStateName}">
<Storyboard>
<BooleanAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup" Storyboard.TargetProperty="IsOpen">
<DiscreteBooleanKeyFrame KeyTime="0" Value="False" />
Expand All @@ -152,7 +152,7 @@
<wpf:PopupEx x:Name="PART_Popup"
wpf:ThemeAssist.Theme="{TemplateBinding DialogTheme}"
Placement="{TemplateBinding Placement}"
PlacementTarget="{Binding ElementName=DialogHostRoot, Mode=OneWay}"
PlacementTarget="{Binding ElementName=PART_DialogHostRoot, Mode=OneWay}"
Style="{TemplateBinding PopupStyle}">
<Grid>
<Border Background="Transparent" IsHitTestVisible="{TemplateBinding CloseOnClickAway}">
Expand Down Expand Up @@ -265,11 +265,11 @@
<ControlTemplate.Resources>
<converters:FirstNonNullConverter x:Key="FirstNonNullConverter" />
</ControlTemplate.Resources>
<Grid x:Name="DialogHostRoot" Focusable="False">
<Grid x:Name="PART_DialogHostRoot" Focusable="False">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="PopupStates">
<VisualStateGroup Name="{x:Static wpf:DialogHost.VisualStateGroupName}">
<VisualStateGroup.Transitions>
<VisualTransition From="Closed" To="Open">
<VisualTransition From="{x:Static wpf:DialogHost.ClosedStateName}" To="{x:Static wpf:DialogHost.OpenStateName}">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}" />
Expand Down Expand Up @@ -308,7 +308,7 @@
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualTransition>
<VisualTransition From="Open" To="Closed">
<VisualTransition From="{x:Static wpf:DialogHost.OpenStateName}" To="{x:Static wpf:DialogHost.ClosedStateName}">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup" Storyboard.TargetProperty="Visibility">
<DiscreteObjectKeyFrame KeyTime="0:0:0.3" Value="{x:Static Visibility.Collapsed}" />
Expand Down Expand Up @@ -351,7 +351,7 @@
</Storyboard>
</VisualTransition>
</VisualStateGroup.Transitions>
<VisualState x:Name="Open">
<VisualState Name="{x:Static wpf:DialogHost.OpenStateName}">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup"
Storyboard.TargetProperty="Visibility"
Expand All @@ -376,7 +376,7 @@
Duration="0" />
</Storyboard>
</VisualState>
<VisualState x:Name="Closed">
<VisualState Name="{x:Static wpf:DialogHost.ClosedStateName}">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="PART_Popup"
Storyboard.TargetProperty="Visibility"
Expand Down
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