Question

在wpf方面，我仍然认为自己是初学者。我想知道两件事

我错了或
如何排查以找到解决方案。

情况：[数据部分]我有： DataModel对象。 DataFilter对象基本上是DataModels +添加函数的集合。和DataFiltersGroup，在DataViewModel中使用并具有DataFilters的集合我有一个DataViewModel对象，它基本上是一个可观察的项集合。我想在Itemscontrol中显示每个DataFilter。

[当前解决方案]我已经构建了一个特殊的combo控件，它源自组合框[基本上是一个按钮+组合框]。故意绑定时，specialcombo工作正常。所以我相信这个问题不是特别的组合。当我将ItemsControl.ItemsSource属性设置为DataFilters的集合并生成SpecialCombo的DataTemplate时，组合框不显示任何结果（如果没有项目，则特殊组合将不显示切换按钮 - 仅显示按钮）。另一种方法 - 下面的绑定方法（2）让我看到下拉togglebutton，但下拉列表是空的，但我知道它不应该是。

这是代码的sumarized提取

public class DataModel :INotifyPropertyChanged
{
    //The Item!!
    public int Index {//Normal get set property}
    public string Name {//Normal get set property}
    public int Parent {//Normal get set property}
    public string FullName {//Normal get set property}
    public string DisplayName {//Normal get set property}
    public bool Static {//Normal get set property}
}

public class DataFilters : DataCollection
{
    public ObservableCollection<DataModel> CombinedData;
    public int FilterIndex{//Property... The index of the current item like Index for DataModel.}
    public string ParentName {//property ButtonContent item}
    public int SelectedItem {//Property}
}

//Used as part of DataVieModel.  Also responsible of building each DataFilters item and some other functions
public class DataFilterGroup : INotifyPropertyChanged
{
    public ObservableCollection<DataFilters> FullCollection;
}

WPF对象

<ItemsControl x:Name="PART_ListBox" HorizontalAlignment="Left" VerticalContentAlignment="Stretch" Margin="0">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <VirtualizingStackPanel Orientation="Horizontal"/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>

加载WPF后代码

//DVM = DataVieModel with some other objects.  Filters = DataFilterGroup
PART_ListBox.ItemsSource = DVM.Filters.FullCollection;
PART_ListBox.ItemTemplate = DataFilterTemplate;

//And DataTemplate (1) - shows no combobox
private static DataTemplate DataFilterTemplate
{
    get
    {
        DataTemplate DFT = new DataTemplate();
        DFT.DataType = typeof(DataFilters);

        FrameworkElementFactory Stack = new FrameworkElementFactory(typeof(VirtualizingStackPanel));
        Stack.SetValue(VirtualizingStackPanel.OrientationProperty, Orientation.Horizontal);

        FrameworkElementFactory Item = new FrameworkElementFactory(typeof(SpecialCombo));
        Item.SetValue(SpecialCombo.ButtonContentProperty, new Binding("ParentName"));
        Item.SetValue(SpecialCombo.ItemsSourceProperty, "CombinedData");
        Item.SetValue(SpecialCombo.DisplayMemberPathProperty, "DisplayName");
        Item.SetValue(SpecialCombo.SelectedValuePathProperty, "Index");
        Item.SetValue(SpecialCombo.SelectedValueProperty, "SelectedItem");
        //Item.SetValue(SpecialCombo.ToggleVisibleProperty, new Binding("ComboVisibility"));
        //Item.SetValue(SpecialCombo.SelectedValueProperty, new Binding("SelectedItem"));

        Stack.AppendChild(Item);

        DFT.VisualTree = Stack;

        return DFT;
    }
}    

//And DataTemplate (2) - shows combobox with no items in dropdown
private static DataTemplate DataFilterTemplate
{
    get
    {
        DataTemplate DFT = new DataTemplate();
        DFT.DataType = typeof(DataFilters);

        FrameworkElementFactory Stack = new FrameworkElementFactory(typeof(VirtualizingStackPanel));
        Stack.SetValue(VirtualizingStackPanel.OrientationProperty, Orientation.Horizontal);

        FrameworkElementFactory Item = new FrameworkElementFactory(typeof(SpecialCombo));
        Item.SetValue(SpecialCombo.ButtonContentProperty, new Binding("ParentName"));
        Item.SetValue(SpecialCombo.ItemsSourceProperty, new Binding("CombinedData"));
        Item.SetValue(SpecialCombo.DisplayMemberPathProperty, "DisplayName");
        Item.SetValue(SpecialCombo.SelectedValuePathProperty, "Index");
        Item.SetValue(SpecialCombo.SelectedValueProperty, "SelectedItem");
        //Item.SetValue(SpecialCombo.ToggleVisibleProperty, new Binding("ComboVisibility"));
        //Item.SetValue(SpecialCombo.SelectedValueProperty, new Binding("SelectedItem"));

        Stack.AppendChild(Item);

        DFT.VisualTree = Stack;

        return DFT;
    }
}

Answer 1

感谢punker 76在另一篇文章中重新构建了问题（这里 - ＆gt; Can one bind a combobox Itemssource from a datatemplate of a ItemsControl），我必须完成以下工作。

DataFilters应该成为一个dependencyobject因此

public class DataFilters : DataCollection
// should become
public class DataFilters : DependencyObject

Observalbe集合也应该改变。所以

public ObservableCollection<DataModel> CombinedData;
// should become
public static readonly DependencyProperty CombinedData= DependencyProperty.Register("CombinedData", typeof(ObservableCollection<DataModel>), typeof(DataFilters), new FrameworkPropertyMetadata());

//and should become a property
public ObservableCollection<DataModel> CombinedData
{
    get { return (ObservableCollection<DataModel>)GetValue(CombinedDataProperty); }
    set { SetValue(CombinedDataProperty, value); }
}

然后在DataTemplate文件中，以下内容应该更改 Item.SetValue（SpecialCombo.ItemsSourceProperty，“CombinedData”）; //应该改为 Item.SetBinding（SpecialCombo.ItemsSourceProperty，new Binding（“CombinedData”））;

我没有完成上面的整个代码，但我认为为了在DataTemplate中绑定组合框类型的项目，所有上述更改都应该是必需的。

数据绑定ItemsControl中的ItemsSource

1 个答案: