Button加入等待动画，先运行软件看下效果

建立BusyFrameAnimation类，在类中创建Button中依赖属性IsBusyProperty

public class BusyFrameAnimation : DependencyObject
    {
        public static bool GetIsBusy(DependencyObject property)
        {
            return (bool)property.GetValue(IsBusyProperty);
        }

        public static void SetIsBusy(DependencyObject property, bool value)
        {
            property.SetValue(IsBusyProperty, value);
        }

        public static readonly DependencyProperty IsBusyProperty =
            DependencyProperty.RegisterAttached("IsBusy", typeof(bool), typeof(BusyFrameAnimation), new PropertyMetadata(false));
    }

local:BusyFrameAnimation.IsBusy="{Binding LoginIsRunning}" 属性绑定LoginIsRunning，设置LoginIsRunning值显示或隐藏等待。

<Button Content="登录"
                            IsDefault="True"
                            Command="{Binding LoginCommand}"
                            local:BusyFrameAnimation.IsBusy="{Binding LoginIsRunning}"
                            CommandParameter="{Binding RelativeSource={RelativeSource AncestorType={x:Type pages:LoginPage}}}" 
                            HorizontalAlignment="Center"/>

 public class BoolenToVisiblityConverter : BaseValueConverter<BoolenToVisiblityConverter>
    {
        public override object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (parameter == null)
                return (bool)value ? Visibility.Hidden : Visibility.Visible;
            else
                return (bool)value ? Visibility.Visible : Visibility.Hidden;
        }

        public override object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

重点部分来了，实现加载动画和旋转效果功能，先去iconfont找个等待矢量图。

<Geometry x:Key="Icon-Waiting">M60.014 542.385c0-37.982 30.385-68.367 68.367-68.367 45.578 0 75.964 30.385 75.964 68.367 0 45.578-30.385 75.964-75.964 75.964-37.982 0-68.367-30.385-68.367-75.964zM151.171 276.512v0c0-53.175 37.982-98.753 91.157-98.753s98.753 45.578 98.753 98.753v0c0 53.175-45.578 91.157-98.753 91.157s-91.157-37.982-91.157-91.157v0zM189.153 815.856v0c0-30.385 22.789-53.175 53.175-53.175s53.175 22.789 53.175 53.175v0c0 30.385-22.789 53.175-53.175 53.175s-53.175-22.789-53.175-53.175zM455.027 929.802v0c0-37.982 22.789-60.772 60.772-60.772s60.772 22.789 60.772 60.772v0c0 37.982-22.789 60.772-60.772 60.772-37.982 0-60.772-22.789-60.772-60.772zM751.287 815.856c0-22.789 15.193-37.982 37.982-37.982s37.982 15.193 37.982 37.982c0 22.789-15.193 37.982-37.982 37.982-22.789 0-37.982-15.193-37.982-37.982zM834.847 542.385c0-30.385 30.385-60.772 68.367-60.772 30.385 0 60.772 30.385 60.772 60.772 0 37.982-30.385 68.367-60.772 68.367-37.982 0-68.367-30.385-68.367-68.367zM660.13 276.512c0-75.964 60.772-129.139 129.139-129.139s129.139 53.175 129.139 129.139c0 68.367-60.772 129.139-129.139 129.139-68.367 0-129.139-60.772-129.139-129.139zM386.66 162.566c0-68.367 60.772-129.139 129.139-129.139s129.139 60.772 129.139 129.139c0 68.367-60.772 129.139-129.139 129.139-68.367 0-129.139-60.772-129.139-129.139z</Geometry>

用label实现加载矢量图，PathData="{DynamicResource Icon-Waiting}"，动画旋转360度和时长设置等属性，Storyboard.TargetProperty="(UIElement.RenderTransform).(RotateTransform.Angle)"From="0"To="360"Duration="0:0:2"

<Style x:Key="SpinningLabel" TargetType="{x:Type Label}">
        <Setter Property="RenderTransformOrigin" Value="0.5,0.5"/>
        <Setter Property="RenderTransform">
            <Setter.Value>
                <RotateTransform/>
            </Setter.Value>
        </Setter>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Label}">
                    <Viewbox x:Name="IconBox" Width="{TemplateBinding FontSize}" Height="{TemplateBinding FontSize}" HorizontalAlignment="Center" VerticalAlignment="Center">
                        <Path Data="{DynamicResource Icon-Waiting}" Fill="{TemplateBinding Foreground}" Stretch="Fill"></Path>
                    </Viewbox>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Style.Resources>
            <Storyboard x:Key="Spin">
                <DoubleAnimation Storyboard.TargetProperty="(UIElement.RenderTransform).(RotateTransform.Angle)"
                                 From="0"
                                 To="360"
                                 Duration="0:0:2"
                                 RepeatBehavior="Forever"/>
            </Storyboard>
        </Style.Resources>

        <Style.Triggers>
            <DataTrigger Binding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=IsVisible}" Value="True">
                <DataTrigger.EnterActions>
                    <BeginStoryboard Name="SpinStoryboard" Storyboard="{StaticResource Spin}"/>
                </DataTrigger.EnterActions>
                <DataTrigger.ExitActions>
                    <RemoveStoryboard BeginStoryboardName="SpinStoryboard"/>
                </DataTrigger.ExitActions>
            </DataTrigger>
        </Style.Triggers>
    </Style>

之前讲过触发有三种方式，事件触发和属性触发都使用过，这里用到数据触发功能。

<DataTriggerBinding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=IsVisible}"Value="True"> 此处代码表示当显示的时候调用Storyboard="{StaticResource Spin}"名称是上面Spin的键。

标签控件显示和旋转功能已经实现了，需要加入到按钮中。

<Style TargetType="{x:Type Button}">
        <Setter Property="Background" Value="{StaticResource WordOrangeBrush}"/>
        <Setter Property="Foreground" Value="{StaticResource ForegroundLightBrush}"/>
        <Setter Property="BorderThickness" Value="0"/>
        <Setter Property="FontSize" Value="30"/>
        <Setter Property="Margin" Value="0,10,0,0"/>
        <Setter Property="Padding" Value="50,10"/>
        
        <Setter Property="local:BusyFrameAnimation.IsBusy" Value="False"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ButtonBase}">
                    <Border x:Name="border"
                            CornerRadius="10"
                            BorderBrush="{TemplateBinding BorderBrush}" 
                            BorderThickness="{TemplateBinding BorderThickness}" 
                            Background="{TemplateBinding Background}" 
                            SnapsToDevicePixels="True">
                        <Grid>
                            <TextBlock Text="{TemplateBinding Content}"
                                    Visibility="{TemplateBinding local:BusyFrameAnimation.IsBusy, Converter={cv:BoolenToVisiblityConverter}}"
                                    Focusable="False"
                                    FontFamily="{TemplateBinding FontFamily}"
                                    FontSize="{TemplateBinding FontSize}"
                                    HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                                    Margin="{TemplateBinding Padding}" 
                                    SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" 
                                    VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>

                            <Label Style="{DynamicResource SpinningLabel}"
                                   FontSize="{TemplateBinding FontSize}"
                                   Foreground="{TemplateBinding Foreground}"
                                   HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                                   VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                                   Visibility="{TemplateBinding local:BusyFrameAnimation.IsBusy, Converter={cv:BoolenToVisiblityConverter}, ConverterParameter=True}"/>
                        </Grid>
                    </Border>
                    <ControlTemplate.Triggers>
                        <EventTrigger RoutedEvent="MouseEnter">
                            <BeginStoryboard>
                                <Storyboard>
                                    <ColorAnimation To="{StaticResource WordBlue}" Duration="0:0:0.3" Storyboard.TargetName="border" Storyboard.TargetProperty="Background.Color"/>
                                </Storyboard>
                            </BeginStoryboard>
                        </EventTrigger>
                        <EventTrigger RoutedEvent="MouseLeave">
                            <BeginStoryboard>
                                <Storyboard>
                                    <ColorAnimation From="{StaticResource WordBlue}" Duration="0:0:0.3" Storyboard.TargetName="border" Storyboard.TargetProperty="Background.Color"/>
                                </Storyboard>
                            </BeginStoryboard>
                        </EventTrigger>
                        <Trigger Property="IsEnabled" Value="False">
                            <Setter Property="Background" TargetName="border" Value="{StaticResource ForegroundDarkBrush}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

默认等待动画是不显示，所以设置依赖属性<SetterProperty="local:BusyFrameAnimation.IsBusy"Value="False"/>

当Visibility="{TemplateBinding local:BusyFrameAnimation.IsBusy, Converter={cv:BoolenToVisiblityConverter}, ConverterParameter=True}" 转换类型cv:BoolenToVisiblityConverter和设置依赖属性BusyFrameAnimation.IsBusy=true时就会显示等待动画。

最后登录按钮绑定命令是异步等待，这里我设置显示等待10秒。

public ICommand LoginCommand
        {
            get
            {
                return new DelegateCommand(async parameter =>
                {
                    await RunCommandAsync(() => this.LoginIsRunning, async () =>
                    {
                        await Task.Delay(10000);
                    });
                });
            }
        }

RunCommandAsync异步方法，参数updatingFlag是LoginIsRunning传的值， updatingFlag.SetPropertyValue(true);显示动画，await action();等待时间后再设置false，隐藏动画效果，显示Button默认文本内容

protected async Task RunCommandAsync(Expression<Func<bool>> updatingFlag, Func<Task> action)
        {
            lock (updatingFlag)
            {
                if (updatingFlag.GetPropertyValue())
                    return;

                updatingFlag.SetPropertyValue(true);
            }

            try
            {
                await action();
            }
            finally
            {
                updatingFlag.SetPropertyValue(false);
            }
        }