Question

我有一个外部'current'属性（int），它表示集合的当前索引。我有一个列表视图，显示此集合。我希望能够根据'current'的值设置集合的'nth'项，即如果current是3，则突出显示集合中的第4项（index = 3）等。我该怎么做？

另一种方法是在项目文本等于另一个外部属性时进行绑定。

Answer 1

要自定义ListView的样式，您可以创建一个DataTrigger，它绑定到View的DataContext的属性以更改当前样式。在此示例中，代码更改背景。

<ListView.ItemContainerStyle>
  <Style TargetType="ListViewItem">
    <Setter Property="Background" Value="Aqua"/>
      <Style.Triggers>
        <DataTrigger Binding="{Binding Path=DataContext.StyleType, RelativeSource={RelativeSource Self}}" Value="1">
          <Setter Property="Background" Value="Chartreuse"/>
        </DataTrigger>
      </Style.Triggers>
  </Style>
</ListView.ItemContainerStyle>

我已经在这里添加了大部分代码，因此您可以尽可能完整地了解正在发生的事情，但我跳过了常见的MVVM基类。

工作原理：

ListView ItemsSource绑定到客户
ListView SelectedItem绑定到客户
ListView.ItemContainerStyle有一个绑定到DataContext.StyleType的DataTrigger
DataContext是一个Customer对象列表，其中包含用户定义的StyleType属性，该属性在代码隐藏中初始化
按钮命令清除StyleType
单击一行会更改下一行的样式
Customer实现了在StyleType更改时触发的INotifyPropertyChanged
DataTrigger改变背景每个ListViewItem

这是XAML，请看DataTrigger：

<Window x:Class="ListViewScrollPosition.Views.ScrollBarwindow"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="Style on Model" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <ListView 
            Grid.Row="0"
            SelectedItem="{Binding Customer}"
            ItemsSource="{Binding Customers}" x:Name="myListView">
            <ListView.ItemContainerStyle>
                <Style TargetType="ListViewItem">
                    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                    <Setter Property="Background" Value="Aqua"/>
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding Path=DataContext.StyleType, RelativeSource={RelativeSource Self}}" Value="1">
                            <Setter Property="Background" Value="Pink"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </ListView.ItemContainerStyle>
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="First Name"
                                    DisplayMemberBinding="{Binding FirstName}" />
                    <GridViewColumn Header="Last Name"
                                    DisplayMemberBinding="{Binding LastName}" />
                    <GridViewColumn Header="Style Type"
                                    DisplayMemberBinding="{Binding StyleType}" />
                </GridView>
            </ListView.View>
        </ListView>
        <Button Grid.Row="1" Content="Change Style" Command="{Binding Path=AlterStyle}"/>
    </Grid>
</Window>

以下是View用于获取Customers并更改StyleType值的ViewModel：

using System.Collections.Generic;
using System.Windows.Input;
using ListViewScrollPosition.Commands;
using ListViewScrollPosition.Models;

namespace ListViewScrollPosition.ViewModels
{
 public class MainViewModel : ViewModelBase
 {
   private DelegateCommand _alterStyleCommand;

   public MainViewModel()
   {
   }

   public ICommand AlterStyle
   {
     get
     {
       if (_alterStyleCommand == null)
        {
          _alterStyleCommand = new DelegateCommand(AlterStyleCommand);
        }
       return _alterStyleCommand;
     }
   }

   private void AlterStyleCommand()
   {
    foreach (var customer in Customers)
    {
      customer.StyleType = 0;
    }
   }

   private void ApplyStyleToNextRow(Customer currentCustomer)
   {
     bool setNext = false;
     foreach (var customer in Customers)
     {
       if (setNext)
       {
         customer.StyleType = 1;
         setNext = false;
       }
       else
       {
         customer.StyleType = 0;
       }

       if (currentCustomer == customer)
       {
         setNext = true;
       }
     }
   }

   private List<Customer> _customers = Customer.GetSampleCustomerList();
   public List<Customer> Customers
   {
     get
     {
        return _customers;
     }
   }

   private Customer _customer = null;
   public Customer Customer
   {
     get
     {
       return _customer;
     }
     set
     {
       _customer = value;
       ApplyStyleToNextRow(_customer);
       OnPropertyChanged("Customer");
     }
   }
 }
}

这是Model，ViewModelBase实现了INotifyPropertyChanged，StyleType在更改时触发OnPropertyChanged，更新每个ListViewItem：

using System;
using System.Collections.Generic;

namespace ListViewScrollPosition.Models
{
  public class Customer : ViewModels.ViewModelBase
  {
    public String FirstName { get; set; }
    public String LastName { get; set; }

    private int _style;
    public int StyleType
    {
      get { return _style;}
      set
      {
        _style = value;
        OnPropertyChanged("StyleType");
      }
    }

    public Customer(String firstName, String lastName, int styleType)
    {
      this.FirstName = firstName;
      this.LastName = lastName;
      this.StyleType = styleType;
    }

    public static List<Customer> GetSampleCustomerList()
    {
     return new List<Customer>(new Customer[4] {
            new Customer("A.", "Zero", 0), 
            new Customer("B.", "One", 1),
            new Customer("C.", "Two", 2),
            new Customer("D.", "Three", 1)
        });
    }
  }
}

以下是设置DataContext的代码隐藏：

using System.Windows;
namespace ListViewScrollPosition.Views
{
  public partial class ScrollBarwindow : Window
  {
    public ScrollBarwindow()
    { 
      InitializeComponent();
      DataContext = new ViewModels.MainViewModel();
    }
  }
}

在listview中设计第n项？

1 个答案: