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如何在Silverlight4中等待状态更改转换完成?

visualstatemanager silverlight-4.0 silverlight wpf c#

gius · 技术社区 · 14 年前

我需要更改控件的状态,然后执行一些操作。具体来说,我希望在隐藏控件之前运行动画。我想这样做:

VisualStateManager.GoToState(control, "Hidden", true); // wait until the transition animation is finished
ParentControl.Children.Remove(control);

3 回复 | 直到 14 年前

Michael S. Scherotter 14 年前

您可以附加情节提要。已完成事件处理程序或附加VisualStateGroup.CurrentStateChangedVisualStateGroup的事件处理程序:

<UserControl
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" mc:Ignorable="d"
x:Class="SilverlightApplication7.MainPage"
Width="640" Height="480">

<Grid x:Name="LayoutRoot" Background="White">
    <VisualStateManager.VisualStateGroups>
        <VisualStateGroup x:Name="VisualStateGroup" >
            <VisualState x:Name="Hidden">
                <Storyboard Completed="OnHidden">
                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="rectangle" d:IsOptimized="True"/>
                </Storyboard>
            </VisualState>
        </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>
    <Rectangle x:Name="rectangle" Fill="#FFF4F4F5" HorizontalAlignment="Left" Height="136" Margin="48,72,0,0" Opacity="0" Stroke="Black" VerticalAlignment="Top" Width="208"/>
</Grid>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace SilverlightApplication7
{
public partial class MainPage : UserControl
{
    public MainPage()
    {
        // Required to initialize variables
        InitializeComponent();

        this.Loaded += new RoutedEventHandler(MainPage_Loaded);
    }

    void MainPage_Loaded(object sender, RoutedEventArgs e)
    {
        VisualStateManager.GoToState(this, "Hidden", true);
    }

    private void OnHidden(object storyboard, EventArgs args)
    {

    }
}

Denis 14 年前

处理此问题的正确方法是在VisualStateGroup上侦听CurrentStateChanged事件,但根据我的经验,它最好是不可靠的,最坏是坏的。

dain 14 年前

实际上,可以在代码中附加已完成的处理程序:

Collection<VisualStateGroup> grps = (Collection<VisualStateGroup>)VisualStateManager.GetVisualStateGroups(this.LayoutRoot);
foreach (VisualStateGroup grp in grps) {
    Collection<VisualState> states = (Collection<VisualState>)grp.States;
    foreach (VisualState state in states) {
        switch (state.Name) {
            case "Intro":
            state.Storyboard.Completed += new EventHandler(Intro_Completed);break;
        }
    }
}

此线程的示例: http://forums.silverlight.net/forums/p/38027/276746.aspx

为我工作的生活项目使用附加行为太!虽然有点恼人,但是我必须为根用户控件使用单独的依赖属性(在VisualStateManager.GoToState)以及LayoutRoot以获取实际的VisualStateGroup集合。