WPF用戶控件內的綁定

Question

為了進入WPF世界並習慣綁定，我創建了一個用戶控件來定義搜索過濾器。 根據所需的過濾器，用戶可以輸入文本，選擇日期或選擇組合框中的項目。 這是一個示例，其中包含三個創建的搜索控件實例，每個實例的類型不同：

好消息是，一切正常，但我不確定是否一切都按預期完成。

SearchUserControl.xaml：

<UserControl x:Class="Zefix.View.UserControls.SearchUserControl"
             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" 
             mc:Ignorable="d" 
             d:DesignHeight="82" 
             d:DesignWidth="300" 
             Height="Auto"
             x:Name="SearchUserControlRoot">
    <Grid>
        <StackPanel>
            <Label Name="LabelHeaderText" Content="{Binding HeaderText, ElementName=SearchUserControlRoot}" />
            <TextBox Name="TextBoxSearchText" Text="{Binding SearchValue, ElementName=SearchUserControlRoot}" Visibility="{Binding TextBoxVisiblity, ElementName=SearchUserControlRoot}" />
            <DatePicker Name="DatePickerSearch" SelectedDate="{Binding SearchValue, ElementName=SearchUserControlRoot}" Visibility="{Binding DatePickerVisiblity, ElementName=SearchUserControlRoot}" />
            <ComboBox Name="ComboBoxSearch" Text="{Binding SearchValue, ElementName=SearchUserControlRoot}" ItemsSource="{Binding AvailableValues, ElementName=SearchUserControlRoot}" Visibility="{Binding ComboBoxVisiblity, ElementName=SearchUserControlRoot}" IsEditable="True" />
        </StackPanel>
    </Grid>
</UserControl>

SearchUserControl.xaml.cs：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows;
using Zefix.DataAccess;

namespace Zefix.View.UserControls {
    /// <summary>
    ///     Interaction logic for SearchUserControl.xaml
    /// </summary>
    public partial class SearchUserControl {

        #region Public Dependency Properties

        /// <summary>
        /// The search value property
        /// </summary>
        public static readonly DependencyProperty SearchValueProperty =
            DependencyProperty.Register("SearchValue", typeof (object), typeof (SearchUserControl));

        /// <summary>
        /// The available values property
        /// </summary>
        public static readonly DependencyProperty AvailableValuesProperty =
            DependencyProperty.Register("AvailableValues", typeof (IEnumerable<object>), typeof (SearchUserControl));

        /// <summary>
        /// The search type property
        /// </summary>
        public static readonly DependencyProperty SearchTypeProperty =
            DependencyProperty.Register("SearchType", typeof (SearchType), typeof (SearchUserControl));

        /// <summary>
        /// The header text property
        /// </summary>
        public static readonly DependencyProperty HeaderTextProperty =
            DependencyProperty.Register("HeaderText", typeof (string), typeof (SearchUserControl));

        #endregion

        #region Private Dependency Properties

        /// <summary>
        /// The combo box visiblity property
        /// </summary>
        private static readonly DependencyProperty ComboBoxVisiblityProperty =
            DependencyProperty.Register("ComboBoxVisiblity", typeof (Visibility), typeof (SearchUserControl));

        /// <summary>
        /// The text box visiblity property
        /// </summary>
        private static readonly DependencyProperty TextBoxVisiblityProperty =
            DependencyProperty.Register("TextBoxVisiblity", typeof (Visibility), typeof (SearchUserControl));

        /// <summary>
        /// The date picker visiblity property
        /// </summary>
        private static readonly DependencyProperty DatePickerVisiblityProperty =
            DependencyProperty.Register("DatePickerVisiblity", typeof (Visibility), typeof (SearchUserControl));

        #endregion

        #region Public Properties

        /// <summary>
        ///     Gets or sets the type of the search.
        /// </summary>
        /// <value>
        ///     The type of the search.
        /// </value>
        public SearchType SearchType {
            get { return (SearchType) GetValue(SearchTypeProperty); }
            set { SetValue(SearchTypeProperty, value); }
        }

        /// <summary>
        ///     Gets or sets the header text.
        /// </summary>
        /// <value>
        ///     The header text.
        /// </value>
        public string HeaderText {
            get { return (string) GetValue(HeaderTextProperty); }
            set { SetValue(HeaderTextProperty, value); }
        }

        /// <summary>
        /// Gets or sets the available values.
        /// </summary>
        /// <value>
        /// The available values.
        /// </value>
        public IEnumerable<object> AvailableValues {
            get { return (IEnumerable<object>) GetValue(AvailableValuesProperty); }
            set { SetValue(AvailableValuesProperty, value); }
        }

        /// <summary>
        /// Gets or sets the search value.
        /// </summary>
        /// <value>
        /// The search value.
        /// </value>
        public object SearchValue {
            get { return GetValue(SearchValueProperty); }
            set { SetValue(SearchValueProperty, value); }
        }

        #endregion

        #region Private Properties

        /// <summary>
        /// Gets or sets the combo box visiblity.
        /// </summary>
        /// <value>
        /// The combo box visiblity.
        /// </value>
        private Visibility ComboBoxVisiblity {
            get { return (Visibility) GetValue(ComboBoxVisiblityProperty); }
            set { SetValue(ComboBoxVisiblityProperty, value); }
        }

        /// <summary>
        /// Gets or sets the date picker visiblity.
        /// </summary>
        /// <value>
        /// The date picker visiblity.
        /// </value>
        private Visibility DatePickerVisiblity {
            get { return (Visibility) GetValue(DatePickerVisiblityProperty); }
            set { SetValue(DatePickerVisiblityProperty, value); }
        }

        /// <summary>
        /// Gets or sets the text box visiblity.
        /// </summary>
        /// <value>
        /// The text box visiblity.
        /// </value>
        private Visibility TextBoxVisiblity {
            get { return (Visibility) GetValue(TextBoxVisiblityProperty); }
            set { SetValue(TextBoxVisiblityProperty, value); }
        }

        #endregion

        #region Constructor

        /// <summary>
        ///     Initializes a new instance of the <see cref="SearchUserControl" /> class.
        /// </summary>
        public SearchUserControl() {
            InitializeComponent();

            DependencyPropertyDescriptor pd = DependencyPropertyDescriptor.FromProperty(SearchTypeProperty, typeof (SearchUserControl));
            pd.AddValueChanged(this, OnSearchTypePropertyChanged);

            // Initialize default parameters
            SearchType = SearchType.Unknown;
        }

        #endregion

        #region Private Methods

        /// <summary>
        /// Called when the search type property has changed.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        private void OnSearchTypePropertyChanged(object sender, EventArgs e) {

            // Hide all editors
            DatePickerVisiblity = Visibility.Collapsed;
            ComboBoxVisiblity = Visibility.Collapsed;
            TextBoxVisiblity = Visibility.Collapsed;

            // Make the correct editor visible
            switch (SearchType) {
                case SearchType.Date:
                    DatePickerVisiblity = Visibility.Visible;
                    break;
                case SearchType.TextSelection:
                    ComboBoxVisiblity = Visibility.Visible;
                    break;
                case SearchType.Text:
                    TextBoxVisiblity = Visibility.Visible;
                    break;
            }
        }

        #endregion
    }
}

從父控件實例化搜索控件：

        <ribbon:Tab Label="Search">
            <ribbon:Group Padding="0,5,0,5">
                <customcontrols:SearchUserControl x:Name="SearchUserControlCompanyName" HeaderText="company name" Margin="5,0,0,0" SearchType="Text" VerticalAlignment="Center" VerticalContentAlignment="Center" />
                <customcontrols:SearchUserControl x:Name="SearchUserControlCompanyNationality" HeaderText="company nationality (ISO3 code)" Margin="5,0,0,0" SearchType="TextSelection" AvailableValues="{Binding Path=CompaniesViewModel.ISO3Codes}" VerticalAlignment="Center" />
                <customcontrols:SearchUserControl x:Name="SearchUserControlDateFounded" HeaderText="date founded" Margin="5,0,0,0" SearchType="Date" VerticalAlignment="Center" VerticalContentAlignment="Center" />
                <ribbon:Button Context="StatusBarItem" Name="ButtonApplyFilter" Label="Search" ImageSourceSmall="/Resources/search_magnifying_glass_find.png" Margin="5,0,0,0" VerticalAlignment="Center" Click="OnButtonApplyFilterClicked" Command="{Binding Path=ApplyFilterCommand}" ScreenTipHeader="Apply the search filter" VerticalContentAlignment="Center" VariantSize="Large" />
            </ribbon:Group>
        </ribbon:Tab>

在SearchControl中，我想根據設置的SearchType顯示正確的組件（textbox，datepicker或combobox）。 為此，已創建xxxVisibility依賴項屬性和屬性（當SearchTypeProperty通知屬性更改事件時，它們將被設置）。 因為沒有理由將它們公開為公開（它們僅在SearchControl中使用），所以我將它們設為私有; MSDN聲明綁定屬性必須是公共的。 該項目編譯並運行沒有問題，但是正在顯示綁定的xxxVisibility屬性的錯誤，並顯示消息“Public member expected”（無法判斷它是visual studio還是resharper告訴我）。

我在WPF概念方面創建此用戶控件的方法是否正確？ xxxVisibility屬性應該是公共的（事件雖然我不想暴露它們）？

Answer 1

這是一個非常難以回答的問題，而不僅僅是“評論”。 在我個人看來，你的UserControl寫得很好，據我所知，並沒有違反任何規則。 雖然我沒有看到聲明private DependencyProperty任何問題，但這是不尋常的。 在這種情況下，開發人員通常選擇使用private DependencyPropertyKey實現public Read Only DependencyProperty DependencyPropertyKey ：

private static readonly DependencyPropertyKey ComboBoxVisiblityPropertyKey
    = DependencyProperty.RegisterReadOnly("ComboBoxVisiblity", typeof(int), 
    typeof(SearchUserControl), new PropertyMetadata(Visibility.Collapsed));

public static readonly DependencyProperty ComboBoxVisiblityProperty
    = ComboBoxVisiblityPropertyKey.DependencyProperty;

public int ComboBoxVisiblity
{
    get { return (int)GetValue(ComboBoxVisiblityProperty); }
    protected set { SetValue(ComboBoxVisiblityPropertyKey, value); }
}

一些開發人員也可能認為創建Visibility類型的屬性而不是使用BoolToVisibilityConverter綁定bool值是不BoolToVisibilityConverter的，但是再次......這是你的特權。 總的來說，干得好！ :)