達到限制時禁用向上或向下按鈕的UpDown控制元件-有解無憂

我的問題基于這篇文章的答案之一： WPF Numeric UpDown 控制元件在哪里？ Squirrel.Downy 先生回答。我想要完成的是一個數字上下控制，當按鈕被按下的時間較長時，增加/減少的量會更大，否則增加/減少是正常的量。此外，當達到最大值/最小值時，按鈕應禁用。我有一個基于 Slider 的樣式，其中包含 2 個 HoldButton（向上/向下，派生自 RepeatButton）型別的按鈕和一個只讀的 TextBlock 值。在 HoldButton 中，我有 2 個 ICommand 的依賴屬性。這些是 ClickAndHoldCommand 和 ClickCommand，它們根據滑鼠按鈕按下的長度從 OnPreviewMouseLeftButtonDown() 或 OnPreviewMouseLeftButtonUp() 執行。在 xaml 中，它們分別系結到 Slider.IncreaseLarge 和 Slider.IncreaseSmall。如何在達到最大值時禁用向上按鈕并在達到最小值時禁用向下按鈕？困難在于，當我例如禁用滑塊時，滑鼠向上事件不再起作用......

<Style TargetType="{x:Type Slider}" x:Key="NumericUpDown">
    <Style.Resources>
        <Style x:Key="RepeatButtonStyle" TargetType="{x:Type RepeatButton}">
            <Setter Property="Focusable" Value="false" />
            <Setter Property="IsTabStop" Value="false" />
            <Setter Property="Padding" Value="0" />
            <Setter Property="Width" Value="20" />
        </Style>
    </Style.Resources>
    <Setter Property="Stylus.IsPressAndHoldEnabled" Value="false" />
    <Setter Property="SmallChange" Value="1" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Slider}">
                <Grid>
                    <Rectangle RadiusX="10" RadiusY="10" Stroke="{StaticResource SolidBrushLightGrey}" Fill="Black" StrokeThickness="1" />
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto" />
                            <RowDefinition Height="Auto" />
                            <RowDefinition Height="Auto" />
                            <RowDefinition Height="Auto" />
                            <RowDefinition Height="Auto" />
                        </Grid.RowDefinitions>
                        <TextBlock Grid.Row="0" x:Name="ControlName" Style="{StaticResource LabelStyle}" Margin="0,5,0,0" />
                        <TextBlock Grid.Row="1" x:Name="ControlUnits" Style="{StaticResource LabelStyle}" Margin="0,5,0,0" />
                        <usercontrols:HoldButton Grid.Row="2" Delay="250" Interval="375" 
                                                 EnableClickHold="True" 
                                                 ClickAndHoldCommand="{x:Static Slider.IncreaseLarge}" 
                                                 ClickCommand="{x:Static Slider.IncreaseSmall}"
                                                 MaxWidth="60" Height="60" Width="60" Style="{StaticResource ButtonStyleGeneral}" Content=" ">
                        </usercontrols:HoldButton>
                        
                        <TextBlock Grid.Row="3" x:Name="Temperature" Style="{StaticResource LabelStyle}" Margin="0,5,0,0" FontSize="30" Text="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=Value, StringFormat=N1}" />

                        <usercontrols:HoldButton Grid.Row="4" Delay="250" Interval="375" 
                                                 EnableClickHold="True" 
                                                 ClickAndHoldCommand="{x:Static Slider.DecreaseLarge}" 
                                                 ClickCommand="{x:Static Slider.DecreaseSmall}" 
                                                 MaxWidth="60" Height="60" Width="60" Style="{StaticResource ButtonStyleGeneral}" Content="-">
                        </usercontrols:HoldButton>
                        
                        <Border x:Name="TrackBackground" Visibility="Collapsed">
                            <Rectangle x:Name="PART_SelectionRange" Visibility="Collapsed" />
                        </Border>
                        <Thumb x:Name="Thumb" Visibility="Collapsed" />
                    </Grid>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

public partial class HoldButton : RepeatButton
{
    private bool buttonIsHeldPressed;

    public HoldButton()
    {
        InitializeComponent();
        buttonIsHeldPressed = false;

        this.PreviewMouseLeftButtonUp  = OnPreviewMouseLeftButtonUp;
        
        // RepeatButton fires click event repeatedly while button is being pressed!
        this.Click  = HoldButton_Click;
    }

    private void HoldButton_Click(object sender, RoutedEventArgs e)
    {
        Trace.WriteLine("HoldButton_Click()");

        if (EnableClickHold)
        {
            if (numberButtonRepeats > 2)
            {
                ClickAndHoldCommand.Execute(this.CommandParameter);
                e.Handled = true;
                buttonIsHeldPressed = true;
            }

            numberButtonRepeats  ;
        }
    }

    public bool EnableClickHold
    {
        get { return (bool)GetValue(EnableClickHoldProperty); }
        set { SetValue(EnableClickHoldProperty, value); }
    }

    public ICommand ClickAndHoldCommand
    {
        get { return (ICommand)GetValue(ClickAndHoldCommandProperty); }
        set { SetValue(ClickAndHoldCommandProperty, value); }
    }

    public ICommand ClickCommand
    {
        get { return (ICommand)GetValue(ClickCommandProperty); }
        set { SetValue(ClickCommandProperty, value); }
    }

    // Using a DependencyProperty as the backing store for ClickAndHoldCommand.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty ClickAndHoldCommandProperty =
        DependencyProperty.Register("ClickAndHoldCommand", typeof(ICommand), typeof(HoldButton), new UIPropertyMetadata(null));

    // Using a DependencyProperty as the backing store for ClickCommand.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty ClickCommandProperty =
        DependencyProperty.Register("ClickCommand", typeof(ICommand), typeof(HoldButton), new UIPropertyMetadata(null));

    // Using a DependencyProperty as the backing store for EnableClickHold.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty EnableClickHoldProperty =
        DependencyProperty.Register("EnableClickHold", typeof(bool), typeof(HoldButton), new PropertyMetadata(false));

    // Using a DependencyProperty as the backing store for MillisecondsToWait.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty MillisecondsToWaitProperty =
        DependencyProperty.Register("MillisecondsToWait", typeof(int), typeof(HoldButton), new PropertyMetadata(0));

    public int MillisecondsToWait
    {
        get { return (int)GetValue(MillisecondsToWaitProperty); }
        set { SetValue(MillisecondsToWaitProperty, value); }
    }

    private int numberButtonRepeats;

    private void OnPreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        if (EnableClickHold)
        {
            numberButtonRepeats = 0;

            if(!buttonIsHeldPressed)
            {
                ClickCommand?.Execute(this.CommandParameter);
            }

            buttonIsHeldPressed = false;
        }
    }

    private void OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        Trace.WriteLine("OnPreviewMouseLeftButtonDown()");
        if (EnableClickHold)
        {
            // When numberButtonRepeats comes above 1 then the button is considered to be pressed long
            if (numberButtonRepeats > 1)
            {
                ClickAndHoldCommand?.Execute(this.CommandParameter);
            }

            numberButtonRepeats  ;
        }
    }
}

<UserControl x:Class="Views.TemperatureControlView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:Views" 
             xmlns:cal="http://www.caliburnproject.org"
             xmlns:controls="clr-namespace:UserControls"
             mc:Ignorable="d" 
             d:DesignHeight="250" d:DesignWidth="150">
    <Slider Minimum="{Binding MinimumTemperature}" 
            Maximum="{Binding MaximumTemperature}" 
            SmallChange="{Binding TemperatureTinySteps}" 
            LargeChange="{Binding TemperatureSmallSteps}" 
            Value="{Binding ControlValue}" 
            Style="{StaticResource NumericUpDown}" />
</UserControl>

uj5u.com熱心網友回復：

您應該擴展Slider控制并在那里實作邏輯。
最后命名RepeatButton元素并將其移動Style到Generic.xaml檔案。

public class CustomSlider : Slider
{
  static CustomSlider()
  {
    DefaultStyleKeyProperty.OverrideMetadata(typeof(CustomSlider), new FrameworkPropertyMetadata(typeof(CustomSlider)));
  }

  public override void OnApplyTemplate()
  {
    base.OnApplyTemplate();
    this.PART_IncreaseButton = GetTemplateChild(nameof(this.PART_IncreaseButton)) as UIElement;
    this.PART_DecreaseButton = GetTemplateChild(nameof(this.PART_DecreaseButton)) as UIElement;
  }

  protected override void OnValueChanged(double oldValue, double newValue)
  {
    base.OnValueChanged(oldValue, newValue);

    if (this.PART_IncreaseButton == null 
      || this.PART_DecreaseButton == null)
    {
      return;
    }

    this.PART_IncreaseButton.IsEnabled = newValue < this.Maximum;
    this.PART_DecreaseButton.IsEnabled = newValue > this.Minimum;
  }

  private UIElement PART_IncreaseButton { get; set; }
  private UIElement PART_DecreaseButton { get; set; }
}

Generic.xaml
名稱HoldButton元素"PART_IncreaseButton"，并"PART_IncreaseButton"讓你可以很容易地找到他們的模板。

<Style TargetType="{x:Type CustomSlider}">
  <Style.Resources>
    <Style x:Key="RepeatButtonStyle" TargetType="{x:Type RepeatButton}">
      <Setter Property="Focusable" Value="false" />
      <Setter Property="IsTabStop" Value="false" />
      <Setter Property="Padding" Value="0" />
      <Setter Property="Width" Value="20" />
    </Style>
  </Style.Resources>
  <Setter Property="Stylus.IsPressAndHoldEnabled" Value="false" />
  <Setter Property="SmallChange" Value="1" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type Slider}">
        <Grid>
          <Rectangle RadiusX="10" RadiusY="10" Stroke="{StaticResource SolidBrushLightGrey}" Fill="Black" StrokeThickness="1" />
          <Grid>
            <Grid.RowDefinitions>
              <RowDefinition Height="Auto" />
              <RowDefinition Height="Auto" />
              <RowDefinition Height="Auto" />
              <RowDefinition Height="Auto" />
              <RowDefinition Height="Auto" />
            </Grid.RowDefinitions>
              
            <TextBlock Grid.Row="0" x:Name="ControlName" Style="{StaticResource LabelStyle}" Margin="0,5,0,0" />
            <TextBlock Grid.Row="1" x:Name="ControlUnits" Style="{StaticResource LabelStyle}" Margin="0,5,0,0" />
              
            <usercontrols:HoldButton x:Name="PART_IncreaseButton" 
                                     Grid.Row="2" 
                                     Delay="250" 
                                     Interval="375" 
                                     EnableClickHold="True" 
                                     ClickAndHoldCommand="{x:Static Slider.IncreaseLarge}" 
                                     ClickCommand="{x:Static Slider.IncreaseSmall}"
                                     MaxWidth="60" 
                                     Height="60" Width="60" 
                                     Style="{StaticResource ButtonStyleGeneral}" 
                                     Content=" " />


            <TextBlock Grid.Row="3" x:Name="Temperature" Style="{StaticResource LabelStyle}" Margin="0,5,0,0" FontSize="30" Text="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=Value, StringFormat=N1}" />

            <usercontrols:HoldButton x:Name="PART_DecreaseButton" 
                                     Grid.Row="4" 
                                     Delay="250" 
                                     Interval="375" 
                                     EnableClickHold="True" 
                                     ClickAndHoldCommand="{x:Static Slider.DecreaseLarge}" 
                                     ClickCommand="{x:Static Slider.DecreaseSmall}" 
                                     MaxWidth="60" 
                                     Height="60" Width="60" 
                                     Style="{StaticResource ButtonStyleGeneral}" 
                                     Content="-" />


              <Border x:Name="TrackBackground" Visibility="Collapsed">
              <Rectangle x:Name="PART_SelectionRange" Visibility="Collapsed" />
            </Border>
            <Thumb x:Name="Thumb" Visibility="Collapsed" />
          </Grid>
        </Grid>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/372426.html

標籤：c# wpf mvvm numericupdown

上一篇：如何隱藏UniformGrid的懸停和單擊事件？

下一篇：WPF-如何在保留標題按鈕的標題欄上顯示控制元件