Question

我目前正在编写一个启动器，我正处于原型设计阶段。

我是WPF的新手但不是MVVM架构的新手，但是，我不确定如何将我的ViewModel绑定到CommandBox视图，因为我在ViewModel中使用方法，也许我正在查看它从错误的角度来看如果我做错了请赐教！：）

我有以下ViewModel，就输入而言，它基本上是启动器的本质：

/// <summary>
/// Provides a buffer of characters in order to search for candidates that matches the buffer.
/// </summary>
public class CommandBufferViewModel : INotifyPropertyChanged
{
    private readonly StringBuilder _input;

    public CommandBufferViewModel()
    {
        _input = new StringBuilder();
    }

    public event PropertyChangedEventHandler PropertyChanged;

    /// <summary>
    /// Deletes a character from the buffer.
    /// </summary>
    public void DeleteKey(int index, int length = 1)
    {
        _input.Remove(index, length);

        OnPropertyChanged(nameof(DeleteKey));
    }

    /// <summary>
    /// Adds a character to the buffer.
    /// </summary>
    public void ProcessKey(int index, char key)
    {
        _input.Insert(index, key);

        OnPropertyChanged(nameof(ProcessKey));
    }

    /// <summary>
    /// Returns results that matches the current buffer.
    /// </summary>
    /// <returns>Results that matches the current buffer.</returns>
    public async Task<CommandResults> Search()
    {
        // NYI

        return default(CommandResults);
    }

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

这里的想法是命令可以存储在远程数据库或您可能喜欢的任何存储中以及本地存储。

（CommandBox视图）TextBox如下所示：

<TextBox
    x:Class="Yalla.Launcher.Views.CommandBox"
    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:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:bs="clr-namespace:Yalla.Launcher.Behaviors"
    mc:Ignorable="d" 
    Width="Auto" Height="Auto" VerticalContentAlignment="Center" BorderThickness="1">
    <i:Interaction.Behaviors>
        <bs:WatermarkBehavior Text="Enter Command... (type ? for help)" />
    </i:Interaction.Behaviors>
</TextBox>

Answer 1

我想我想到了这一点，我只需要一个ViewModel来保存用户正在搜索的命令的文本，我将把它作为视图和启动器搜索服务之间的粘合剂。

这样的事情：

namespace Yalla.Launcher.ViewModels
{
    using System.ComponentModel;

    using Commands;

    using Features.Commands.Search;

    public class SearchViewModel : INotifyPropertyChanged, ISearchableText
    {
        private SearchCommandHandler _enterCommandHandler;

        private string _searchText;

        public event PropertyChangedEventHandler PropertyChanged;

        public SearchCommandHandler Search => _enterCommandHandler ?? (_enterCommandHandler = new SearchCommandHandler(new SearchService(this)));

        public string SearchText
        {
            get
            {
                return _searchText;
            }

            set
            {
                _searchText = value;

                OnPropertyChanged(nameof(SearchText));
            }
        }

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

最后，我将它绑定到TextBox，如下所示：

<ctrls:LauncherTextBox
    x:Class="Yalla.Launcher.Views.LauncherSearchBox"
    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:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:bs="clr-namespace:Yalla.Launcher.Behaviors"
    xmlns:ctrls="clr-namespace:Yalla.Launcher.Controls"
    xmlns:vm="clr-namespace:Yalla.Launcher.ViewModels"
    mc:Ignorable="d"
    Width="Auto" Height="Auto" 
    VerticalContentAlignment="Center" BorderThickness="1" 
    Text="{Binding SearchText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
    <ctrls:LauncherTextBox.DataContext>
        <vm:SearchViewModel />
    </ctrls:LauncherTextBox.DataContext>
    <i:Interaction.Behaviors>
        <bs:WatermarkBehavior Text="Enter Command... (type ? for help)" />
    </i:Interaction.Behaviors>
    <TextBox.InputBindings>
        <KeyBinding Key="Return" Command="{Binding Search}"></KeyBinding>
    </TextBox.InputBindings>
</ctrls:LauncherTextBox>

非常简单，但这可能就是我需要开始的。

在WPF中创建启动器

1 个答案: