Question

我正在使用dapper使用列表从数据库中检索一些数据。我已经能够使用

使用ListBox做到这一点

private void UpdateBinding()
{
    displayLastNameLB.ItemsSource = people;
    displayLastNameLB.DisplayMemberPath = "FullInfo";
}

，现在我想在TextBlock中显示它，但是我找不到方法。 ItemSource和DisplayMemberPath的等效文本块是什么？这是完整的代码。

public partial class MainWindow : Window
{
    List<Person> people = new List<Person>();

    public MainWindow()
    {
        InitializeComponent();

        UpdateBinding();
    }

    private void UpdateBinding()
    {
        displayLastNameLB.ItemsSource = people;
        displayLastNameLB.DisplayMemberPath = "FullInfo";
    }

    private void Search_Click(object sender, RoutedEventArgs e)
    {
        DataAccess db = new DataAccess();
        people = db.GetPeople(lastNameTB.Text);

        UpdateBinding();
    }
}

人员列表

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
    public string PhoneNumber { get; set; }

    public string FullInfo
    {
        get
        {
            return $"{ FirstName } { LastName } ({ PhoneNumber })";
        }
    }

    public string FirstNameOnly
    {
        get
        {
            return $"{ FirstName }";
        }
    }
}

Answer 1

似乎您想使用ComboBox。在那里，您有一个选定的项目，并有一个项目源供用户选择。

ComboBox如下所示：

<ComboBox ItemsSource="{Binding people}" DisplayMemberPath="FullInfo" IsEditable="True"/>

使用IsEditable="True"，用户可以输入自定义值，看起来像TextBox

Answer 2

只需在XAML中将ListBox替换为TextBlock并设置Text属性：

public partial class MainWindow : Window
{
    List<Person> people = new List<Person>();

    public MainWindow()
    {
        InitializeComponent();

        UpdateBinding();
    }

    private void UpdateBinding()
    {
        if (people != null && people.Count > 0)
        {
            textBlock.Text = people[0].FullInfo;
        }
    }

    private void Search_Click(object sender, RoutedEventArgs e)
    {
        DataAccess db = new DataAccess();
        people = db.GetPeople(lastNameTB.Text);
        UpdateBinding();
    }
}

Answer 3

在WPF中，执行此操作的首选方法是使用DataBinding和模型以及支持INotifyPropertyChanged的视图模型。在您的示例中，我在Window.DataContext中看不到任何对象，因此我假设它只是Window本身。这是一个如何实现此目标的代码示例：

// MainViewModel.cs
public class MainViewModel : ObservableObject
{
    public MainViewModel()
    {
        searchCommand = new RelayCommand(SearchExecute);
        People = new ObservableCollection<Person>();
    }

    private ObservableCollection<Person> people;
    public ObservableCollection<Person> People
    {
        get { return people; }
        protected set { Set(ref people, value); }
    }

    private string lastNameTB;
    public string LastNameTB
    {
        get { return lastNameTB; }
        set { Set(ref lastNameTB, value); }
    }

    private Person selectedPerson;
    public Person SelectedPerson
    {
        get { return selectedPerson; }
        set { Set(ref selectedPerson, value); }
    }

    private RelayCommand searchCommand;
    public ICommand SearchCommand
    {
        get { return searchCommand; }
    }

    private void SearchExecute(object _)
    {
        DataAccess db = new DataAccess();
        var data = db.GetPeople(LastNameTB);
        var results = new ObservableCollection<Person>(data);
        People = results;
        SelectedPerson = results.FirstOrDefault();
    }
}

// Person.cs
public class Person : ObservableObject
{
    private string firstName;
    public string FirstName
    {
        get { return firstName; }
        set { Set(ref firstName, value); FullInfo = null; }
    }

    private string lastName;
    public string LastName
    {
        get { return lastName; }
        set { Set(ref lastName, value); FullInfo = null;  }
    }

    private string email;
    public string Email
    {
        get { return email; }
        set { Set(ref email, value); }
    }

    private string phoneNumber;
    public string PhoneNumber
    {
        get { return phoneNumber; }
        set { Set(ref phoneNumber, value); FullInfo = null;  }
    }

    private string fullInfo;
    public string FullInfo
    {
        get { return fullInfo; }
        set
        {
            value = $"{FirstName} {LastName} ({PhoneNumber})";
            Set(ref fullInfo, value);
        }
    }
}

// MainWindow.xaml
<Window x:Class="YourNameSpace.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:vm="clr-namespace:YourNameSpace.ViewModels"
        mc:Ignorable="d"
        Title="Search"
        Height="400" Width="600"
        MinHeight="150" MinWidth="250">
    <Window.DataContext>
        <vw:MainViewModel />
    </Window.DataContext>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <Label Grid.Row="0" Grid.Column="0">Last Name</Label>
        <TextBox Grid.Row="0" Grid.Column="1"
                 Text="{Binding LastNameTB,UpdateSourceTrigger=PropertyChanged}" />

        <Label Grid.Row="1" Grid.Column="0">Last Name</Label>
        <ListView Grid.Row="1" Grid.Column="1"
                  ItemsSource="{Binding People,Mode=OneWay}"
                  SelectedItem="{Binding SelectedPerson}">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="First Name" Width="80" DisplayMemberBinding="{Binding FirstName}" />
                    <GridViewColumn Header="Last Name" Width="80" DisplayMemberBinding="{Binding LastName}" />
                    <GridViewColumn Header="Phone Number" Width="80" DisplayMemberBinding="{Binding PhoneNumber}" />
                    <GridViewColumn Header="Email" Width="80" DisplayMemberBinding="{Binding Email}" />
                </GridView>
            </ListView.View>
        </ListView>

        <Grid Grid.Row="2" Grid.ColumnSpan="2">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="Auto"/>
            </Grid.ColumnDefinitions>
            <Button Grid.Column="1" MinHeight="26" MinWidth="80" Command="{Binding SearchCommand}">Search</Button>
        </Grid>
    </Grid>
</Window>

// ObservableObject.cs (if you use an MVVM framework, there will most likely be a different base object)
public abstract class ObservableObject : INotifyPropertyChanged
{
    public void RaisePropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    protected virtual bool Set<T>(ref T field, T value, bool doNotCheckEquality = false, [CallerMemberName] string propertyName = null)
    {
        if (!doNotCheckEquality)
        {
            if (EqualityComparer<T>.Default.Equals(field, value)) return false;
        }
        var args = new PropertyChangedEventArgs<T>(propertyName);
        field = value;
        RaisePropertyChanged(propertyName, args);
        return true;
    }
}

// RelayCommand.cs (just a simple version of RelayCommand; there are many different implementations)
public class RelayCommand : ICommand
{
    private readonly Action<object> _execute;
    private readonly Predicate<object> _canExecute;

    public RelayCommand(Action<object> execute)
        : this(execute, null)
    { }

    public RelayCommand(Action<object> execute, Predicate<object> canExecute)
    {
        if (execute == null)
            throw new ArgumentNullException(nameof(execute));

        _execute = execute;
        _canExecute = canExecute;
    }

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    [DebuggerStepThrough]
    public virtual bool CanExecute(object parameter)
    {
        return _canExecute == null || _canExecute(parameter);
    }

    public virtual void Execute(object parameter)
    {
        _execute(parameter);
    }

    public void RaiseCanExecuteChanged()
    {
        CommandManager.InvalidateRequerySuggested();
    }
}

TextBlock的ItemSource / DataSource

3 个答案: