ItemTemplateSelector

Posted 2021-02-20 lonelyxmas

原文:ItemTemplateSelector

ItemTemplateSelector的中文翻译是模板选择器

是用来选择模板。

他的用法稍有不同，他必须派生于DataTemplateSelector类。

然后重写SelectTemplate这个方法,方法内由两个参数，一是对象所绑定的数据，二是你绑定的元素。方法有返回类型为DataTemplate的，不过默认值为Null

 

xaml则是通过绑定的方式。

 

模板选择的用比较广。

 这里就介绍默认的使用方式。

通过数据或者对象元素来选择模板

 

选择器类

using System.Windows;
using System.Windows.Controls;

namespace WinMenu
{
    public class Select: DataTemplateSelector
    {
        private int i = 0;
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            var u = container as FrameworkElement;

            i++;

            if (i % 2 == 0)
                return u.FindResource("d1") as DataTemplate;
            else
                return u.FindResource("d2") as DataTemplate;
    
             
        }
    }
}

 

xaml代码：

 <Window.Resources>
        <local:Select  x:Key="sl2"/>

        <DataTemplate x:Key="d1">
            <Image x:Name="image" Height="150"  Width="300" Source="{Binding Image}"  />
        </DataTemplate>
        <DataTemplate x:Key="d2">
            <Image x:Name="image" Height="100" Width="100" Source="{Binding Image}"  />
        </DataTemplate>
        <Storyboard x:Key="S2">
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[2].(RotateTransform.Angle)" >
                <EasingDoubleKeyFrame KeyTime="0" Value="30"/>
                <EasingDoubleKeyFrame KeyTime="0" Value="30"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.4" Value="-5"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="0"/>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" >
                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1"/>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" >
                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>
    </Window.Resources>
    <Grid>
        <ListBox ItemTemplateSelector="{StaticResource sl2}"  x:Name="ListBoxFile" Margin="0,0,0,119"   >
            <ListBox.ItemsPanel>
                <ItemsPanelTemplate>
                    <StackPanel Orientation="Horizontal"/>
                </ItemsPanelTemplate>
            </ListBox.ItemsPanel>
            <ListBox.ItemContainerStyle>
                <Style  TargetType="ListBoxItem">
                    <Setter Property="RenderTransform" >
                        <Setter.Value>
                            <TransformGroup>
                                <ScaleTransform/>
                                <SkewTransform/>
                                <RotateTransform/>
                                <TranslateTransform/>
                            </TransformGroup>
                        </Setter.Value>
                    </Setter>
                    <Style.Triggers>
                        <EventTrigger  RoutedEvent="FrameworkElement.Loaded">
                            <BeginStoryboard Storyboard="{StaticResource S2}"/>
                        </EventTrigger>
                    </Style.Triggers>
                </Style>
            </ListBox.ItemContainerStyle>
        </ListBox>
        <Button Click="Button_Click" Margin="451,321,0,0"/>

    </Grid>

 

图片