C＃WPF問題：無法正確初始化組合框選擇的值

Question

我的代碼試圖為我自己的數據結構的對象列表動態創建組合框。 每個對象都包含一個值列表，這些值將作為其項目填充到comboBox中。 該對象還包含一個名為“ SelectedValue”的值。 我希望每個組合框默認顯示此“ SelectedValue”。 但這是行不通的。 每次顯示視圖后，每個組合框僅將其第一項顯示為選定值。

這是我的XAML代碼：

<Window x:Class="WpfApplication2.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <ListView ItemsSource="{Binding ViewItemList}" SelectionMode="Single" SelectedItem="{Binding Path=SelectedList}" HorizontalAlignment="Left" Height="218" Margin="44,30,0,0" VerticalAlignment="Top" Width="377">
        <ListView.View>
            <GridView>
                <GridViewColumn >
                    <GridViewColumn.CellTemplate>
                        <DataTemplate>
                            <ComboBox ItemsSource="{Binding ComboBoxItemList, Mode=OneWay}" SelectedValue="{Binding SelectedValue, Mode=TwoWay}" IsSynchronizedWithCurrentItem="True" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Margin="5,0"  />
                        </DataTemplate>
                    </GridViewColumn.CellTemplate>
                </GridViewColumn>
            </GridView>
        </ListView.View>
    </ListView>
</Grid>

這是后面的代碼：

public class ComboboxViewModel : DependencyObject
{
    private ObservableCollection<ComboBoxItemsList> m_viewItemlist;
    public ObservableCollection<ComboBoxItemsList> ViewItemList
    {
        get
        {
            return m_viewItemlist;
        }
        set
        {
            m_viewItemlist = value;
        }
    }

    private ComboBoxItemsList m_selectedList;
    public ComboBoxItemsList SelectedList
    {
        get
        {
            return m_selectedList;
        }
        set
        {
            m_selectedList = value;
        }
    }

    public ComboboxViewModel(List<ComboBoxItemsList> ml)
    {
        m_viewItemlist = new ObservableCollection<ComboBoxItemsList>();
        foreach (ComboBoxItemsList item in ml)
        {
            m_viewItemlist.Add(item);
        }
        this.m_selectedList = ml[0];
    }
}

//a class to hold data structure to be shown in one combobox
public class ComboBoxItemsList : DependencyObject
{
    private List<string> m_comboBoxItemList;
    public List<string> ComboBoxItemList
    {
        get { return m_comboBoxItemList; }
    }

    private string m_selectedValue;
    public string SelectedValue
    {
        get { return (string)GetValue(SelectedItemProperty); }
        set
        {
            SetValue(SelectedItemProperty, (string)value);
        }
    }

    public static readonly DependencyProperty SelectedItemProperty =
        DependencyProperty.Register("SelectedValue", typeof(string), typeof(ComboBoxItemsList),
        new PropertyMetadata(OnSelectedValueChanged));

    private static void OnSelectedValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        ComboBoxItemsList curModInfo = d as ComboBoxItemsList;
        if (curModInfo != null)
        {
            string oldVersion = e.OldValue as string;
            string newVersion = e.NewValue as string;
            curModInfo.SelectedValueChanged(oldVersion, newVersion);
        }
    }

    private void SelectedValueChanged(string oldValue, string newValue)
    {
        m_selectedValue = newValue;
    }

    public ComboBoxItemsList(List<string> list, string defaultVal)
    {
        m_comboBoxItemList = list;
        m_selectedValue = defaultVal;
    }
}


//This is main window to start the program
public MainWindow()
    {
        InitializeComponent();

        List<ComboBoxItemsList> mm = new List<ComboBoxItemsList>();
        List<string> nums = new List<string>();
        nums.Add("1");
        nums.Add("2");
        nums.Add("3");
        ComboBoxItemsList m1 = new ComboBoxItemsList(nums, "2");
        mm.Add(m1);
        List<string> letters = new List<string>();
        letters.Add("a");
        letters.Add("b");
        letters.Add("c");
        ComboBoxItemsList m2 = new ComboBoxItemsList(letters, "b");
        mm.Add(m2);
        ComboboxViewModel vm = new ComboboxViewModel(mm);
        this.DataContext = vm;
    }

Answer 1

您的代碼看起來不錯。 您只需要刪除IsSynchronizedWithCurrentItem =“ True”或在您的視圖中使其為false並在ComboBoxItemsList的構造函數中進行更改

 public ComboBoxItemsList(List<string> list, string defaultVal)
            {
                m_comboBoxItemList = list;
                SelectedValue = defaultVal;
            }