Xamarin ListView 选择有助于导航到新的 ListView

Question

我是 xamarin 的新手，所以仍在学习它的所有功能和限制。我很想知道您是否可以从列表视图的选择重定向到另一个包含基于外键的列表视图的页面。在此示例中，外键是 CompanyID。谢谢！

型号：

 public class Company
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
 public class WellGroup
    {
        public int ID { get; set; }
        public string Name { get; set; }
        public int CompanyID { get; set; }
    }

xaml:

 <ListView x:Name="CompaniesCollection"
                ItemsSource="{Binding CompaniesCollection}"
                SelectionMode="Single"
                HasUnevenRows="True"
                ItemSelected="Companies_Selection">
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                    <StackLayout Padding="10" x:DataType="model:Company">
                        <Label Text="{Binding Name}" 
                                        FontSize="Large"
                                        VerticalOptions="Center"/>
                    </StackLayout>

                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

Answer 1

您可以根据具体的CompanyID通过索引显示Company ID和Name。

第2页：显示公司ID

Xaml:

  <ListView x:Name="CompaniesCollection"
            ItemsSource="{Binding CompaniesCollection}"
            SelectionMode="Single"
            HasUnevenRows="True"
            ItemSelected="Companies_Selection">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <ViewCell>
                        <StackLayout Padding="10" x:DataType="model:WellGroup">
                            <Label Text="{Binding CompanyID}" 
                                    FontSize="Large"
                                    VerticalOptions="Center"/>
                        </StackLayout>

                    </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

后面的代码：

   public partial class Page2 : ContentPage
{
  
    public Page2()
    {
        InitializeComponent();
       
        this.BindingContext = new WellGroupViewModel();
    }

    private async void Companies_Selection(object sender, SelectedItemChangedEventArgs e)
    {
        var index = e.SelectedItemIndex;
       
        await Navigation.PushAsync(new Page3(index));
    }
}
public class Company
{

    public int ID { get; set; }
    public string Name { get; set; }
}

public class WellGroup 
{
   public List<Company> Companies { get; set; }
    public int CompanyID { get; set; }
}
public class WellGroupViewModel
{
    public List<WellGroup> CompaniesCollection { get; set; }

    public WellGroupViewModel()
    {
        var C1 = new WellGroup();

        C1.Companies = new List<Company>() {
          new Company(){ ID=1, Name="A"},
            new Company(){ ID=1, Name="B"},
            new Company(){ ID=1, Name="C"},
            new Company(){ ID=1, Name="D"}
        };
     
        C1.CompanyID = 111;

        var C2 = new WellGroup();
        C2.Companies = new List<Company>()
        {
             new Company(){ ID=2, Name="A"},
            new Company(){ ID=2, Name="B"},
            new Company(){ ID=2, Name="C"},
            new Company(){ ID=2, Name="D"}
        } ;
        C2.CompanyID = 222;

        var C3 = new WellGroup();
        C3.Companies = new List<Company>()
        {
             new Company(){ ID=3, Name="A"},
            new Company(){ ID=3, Name="B"},
            new Company(){ ID=3, Name="C"},
            new Company(){ ID=3, Name="D"}
        };
        
        C3.CompanyID = 333;
        CompaniesCollection = new List<WellGroup> { C1, C2, C3 };


    }
}

Page3：根据CompanyID显示ID、Name

Xaml:

  <ListView x:Name="CompaniesCollection"
            ItemsSource="{Binding List}"
            SelectionMode="Single"
            HasUnevenRows="True">

        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                    <StackLayout Padding="10" Orientation="Horizontal" >
                        <Label Text="{Binding ID}" 
                              
                                    VerticalOptions="Center"/>
                        <Label Text="{Binding Name}" 
                                
                                    VerticalOptions="Center"/>
                    </StackLayout>

                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

后面的代码：

 public partial class Page3 : ContentPage
{
    private List<Company> _companies;
   public List<Company> List
    {
        get { return _companies; }
        set
        {
            _companies = value;
            OnPropertyChanged("List");
        }
    }

    public Page3(int index)
    {
        InitializeComponent();
        List = new List<Company>();
        List = ((new WellGroupViewModel()).CompaniesCollection[index]).Companies;
        this.BindingContext = this;
    }
}

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