■ IsNullOrEmptyStateTrigger 엘리먼트의 Value 속성을 사용해 값이 NULL 또는 빈 경우에 따라 처리하는 방법을 보여준다.
※ 비주얼 스튜디오에서 TestProject(Unpackaged) 모드로 빌드한다.
※ TestProject.csproj 프로젝트 파일에서 WindowsPackageType 태그를 None으로 추가했다.
▶ MainPage.xaml
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<?xml version="1.0" encoding="utf-8"?> <Page x:Class="TestProject.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:ctw="using:CommunityToolkit.WinUI" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" FontFamily="나눔고딕코딩" FontSize="16"> <Grid> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="TextBoxStates"> <VisualState x:Name="TextBoxNotEmptyState" /> <VisualState x:Name="TextBoxEmptyState"> <VisualState.StateTriggers> <ctw:IsNullOrEmptyStateTrigger Value="{Binding Text, ElementName=textBox, Mode=OneWay}" /> </VisualState.StateTriggers> <VisualState.Setters> <Setter Target="textBox.BorderBrush" Value="Red" /> <Setter Target="errorTextBlock.Visibility" Value="Visible" /> </VisualState.Setters> </VisualState> </VisualStateGroup> <VisualStateGroup x:Name="ListBoxStates"> <VisualState x:Name="ListNotEmptyState" /> <VisualState x:Name="ListEmptyState"> <VisualState.StateTriggers> <ctw:IsNullOrEmptyStateTrigger Value="{Binding Items, ElementName=listBox, Mode=OneWay}" /> </VisualState.StateTriggers> <VisualState.Setters> <Setter Target="removeButton.IsEnabled" Value="False" /> <Setter Target="emptyTextBlock.Visibility" Value="Visible" /> </VisualState.Setters> </VisualState> </VisualStateGroup> </VisualStateManager.VisualStateGroups> <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" Spacing="10"> <TextBox Name="textBox" Header="The TextBox below will warn if it is empty." Text="" /> <TextBlock Name="errorTextBlock" VerticalAlignment="Center" Foreground="{ThemeResource SystemFillColorCriticalBrush}" Text="* required" Visibility="Collapsed" /> <TextBlock Name="emptyTextBlock" Margin="0 20 0 0" Text="List is empty, add some items" Visibility="Collapsed" /> <StackPanel Orientation="Horizontal"> <Button Name="addButton" Margin="0 0 5 0" Content="Add" /> <Button Name="removeButton" Content="Remove" /> </StackPanel> <ListView Name="listBox" HorizontalAlignment="Left"> <ListView.ItemTemplate> <DataTemplate x:DataType="x:String"> <Grid> <TextBlock Text="{Binding}" /> </Grid> </DataTemplate> </ListView.ItemTemplate> </ListView> </StackPanel> </Grid> </Page> |
▶ MainPage.xaml.cs
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using Microsoft.UI.Xaml; using Microsoft.UI.Xaml.Controls; namespace TestProject; /// <summary> /// 메인 페이지 /// </summary> public sealed partial class MainPage : Page { //////////////////////////////////////////////////////////////////////////////////////////////////// Constructor ////////////////////////////////////////////////////////////////////////////////////////// Public #region 생성자 - MainPage() /// <summary> /// 생성자 /// </summary> public MainPage() { InitializeComponent(); this.addButton.Click += addButton_Click; this.removeButton.Click += removeButton_Click; } #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Private #region Add 버튼 클릭시 처리하기 - addButton_Click(sender, e) /// <summary> /// Add 버튼 클릭시 처리하기 /// </summary> /// <param name="sender">이벤트 발생자</param> /// <param name="e">이벤트 인자</param> private void addButton_Click(object sender, RoutedEventArgs e) { if(this.listBox != null) { this.listBox.Items.Add("Item"); } } #endregion #region Remove 버튼 클릭시 처리하기 - removeButton_Click(sender, e) /// <summary> /// Remove 버튼 클릭시 처리하기 /// </summary> /// <param name="sender">이벤트 발생자</param> /// <param name="e">이벤트 인자</param> private void removeButton_Click(object sender, RoutedEventArgs e) { if(this.listBox != null) { this.listBox.Items.RemoveAt(0); } } #endregion } |
