Question

我的测试应用程序中包含以下代码。

XAML文件：

<Window x:Class="TestWpfApplication.MainWindow"
        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"
        xmlns:local="clr-namespace:TestWpfApplication"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">

    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>
<Grid>
    <CheckBox Grid.Row="0" IsChecked="{Binding IsItemEnabled}" Margin="11,30,-10,129">IsItemEnabled</CheckBox>
    <ComboBox Grid.Row="0" Margin="15,54,352,225" ItemsSource="{Binding Source={StaticResource dataFromEnum}}">
        <ComboBox.ItemContainerStyle>
            <Style TargetType="{x:Type ComboBoxItem}">
                <Setter Property="IsEnabled">
                    <Setter.Value>
                        <MultiBinding Converter="{StaticResource EnabledConverter}">
                            <Binding  RelativeSource="{RelativeSource Self}" Path="Content" />
                            <Binding  RelativeSource="{RelativeSource PreviousData}" Path="IsItemEnabled" />
                        </MultiBinding>
                    </Setter.Value>
                </Setter>
            </Style>
        </ComboBox.ItemContainerStyle>
    </ComboBox>
</Grid>
</Window>

ViewModel

 using System.ComponentModel;
    using System.Runtime.CompilerServices;
    using TestWpfApplication.Annotations;

    namespace TestWpfApplication
    {
        public class MainWindowViewModel : INotifyPropertyChanged
        {
            private bool _isItemEnabled;
            public event PropertyChangedEventHandler PropertyChanged;

            public bool IsItemEnabled
            {
                get { return _isItemEnabled; }
                set
                {
                    _isItemEnabled = value;
                    OnPropertyChanged(nameof(IsItemEnabled));
                }
            }

            [NotifyPropertyChangedInvocator]
            protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
            {
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

转换器

public class EnabledConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        return values[0].ToString() != "Time" || (bool)parameter != false;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

当组合框与enum绑定时，如何执行相同的功能？它有可能吗？

public enum OpTypes
{
    Time,
    Cost,
    Fuel
}

在我的转换器中，我得到{DependencyProperty.UnsetValue}而不是true或false，而在第二个参数值中我得到了enum的值。另一个问题是转换器仅在我打开组合框时第一次触发。或者如何做到正确？请给我任何建议。提前谢谢。

Answer 1

现在它有效）感谢所有

  using System.Collections.Generic;
    using System.ComponentModel;
    using System.Runtime.CompilerServices;
    using TestWpfApplication.Properties;

    namespace TestWpfApplication
    {
        public class MainWindowViewModel : INotifyPropertyChanged
        {
            private bool _isItemEnabled;
            private IList<OptType> _optimizationTypes;
            private OptimizeTypes _selectedIndex;
            public event PropertyChangedEventHandler PropertyChanged;

            public OptimizeTypes SelectedIndex
            {
                get { return _selectedIndex;}
                set
                {
                    _selectedIndex = value;
                    OnPropertyChanged(nameof(SelectedIndex));
                }
            }


            public IList<OptType> OptimizationTypes
            {
                get { return _optimizationTypes; }
                set
                {
                    _optimizationTypes = value;
                    OnPropertyChanged(nameof(OptimizationTypes));
                }
            }

            public bool IsItemEnabled
            {
                get { return _isItemEnabled; }
                set
                {
                    _isItemEnabled = value;
                    InitOptimizationTypes(value);
                    OnPropertyChanged(nameof(IsItemEnabled));
                }
            }


            public MainWindowViewModel()
            {                        
                InitOptimizationTypes(false);
            }

            private  void InitOptimizationTypes(bool isEnabled)
            {
                OptimizationTypes = new List<OptType>
                {
                    new OptType
                    {
                        TypeName = "Time",
                        IsItemEnabled = isEnabled,
                    },
                    new OptType
                    {
                        TypeName = "Cost",
                        IsItemEnabled = true,
                    },
                    new OptType
                    {
                        TypeName = "Fuel",
                        IsItemEnabled = true,
                    }
                };
            }

            [NotifyPropertyChangedInvocator]
            protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
            {
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

using System.Collections;

namespace TestWpfApplication
{
    public class OptType
    {
        public string TypeName { get;  set; }
        public bool IsItemEnabled { get;  set; }
    }
}

          <Window x:Class="TestWpfApplication.MainWindow"
            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"
            xmlns:local="clr-namespace:TestWpfApplication"
            mc:Ignorable="d"
            Title="MainWindow" Height="350" Width="525">

        <Window.DataContext>
            <local:MainWindowViewModel />
        </Window.DataContext>

        <Grid>
            <CheckBox Grid.Row="0" IsChecked="{Binding IsItemEnabled}" Margin="11,30,15,129">IsItemEnabled</CheckBox>
            <ComboBox Grid.Row="0" Margin="15,54,352,231" IsSynchronizedWithCurrentItem="True"
                      ItemsSource="{Binding OptimizationTypes}" DisplayMemberPath="TypeName"  
                      SelectedIndex="{Binding SelectedIndex,  Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                      >
                <ComboBox.ItemContainerStyle>
                    <Style TargetType="{x:Type ComboBoxItem}">
                        <Setter Property="IsEnabled" Value="{Binding IsItemEnabled}"/>
                    </Style>
                </ComboBox.ItemContainerStyle>
                </ComboBox>
        </Grid>
    </Window

>

禁用绑定组合框

1 个答案: