Question

如何更改ComboBox项时使用ContentPresenter更改内容？更改项目时-未选择模板，但在“窗口加载”模板上选择了正确的模板。如何在下面修复我的示例？

我尝试设置 Content =“ {Binding SelectedDocTypeID}” 并将组合框项目更改为调用方法SelectTemplate，但是为什么同一个MyModelObject属性不能这样做呢？如果我不使用这种方法，那么在DataTemplate中，我需要像这样重新绑定： MyModelObject .Name等（并稍微改变一下DataTemplateSelector）。但是我不想绑定到DataTemplate中的对象名称。

我的模型和组合框数据类是：

public class MyData
{
    public string Name { get; set; }
    public string SubName { get; set; }
    public int? DocTypeID { get; set; }
    // etc
}

public class MyDic
{
    public int ID { get; set; }
    public string Name { get; set; }
}

我的视图模型是：

public class MyViewModel : INotifyPropertyChanged
{
    public List<MyDic> MyDicList { get; set; }

    public MyData MyModelObject { get; set; }

    public int? SelectedDocTypeID
    {
        get { return MyModelObject.DocTypeID; }
        set
        {
            MyModelObject.DocTypeID = value;
            OnPropertyChanged();
            OnPropertyChanged("MyModelObject");
        }
    }                      

    public MyViewModel()
    {
        MyDicList = new List<MyDic>()
        {
            new MyDic() { ID = 1, Name = "First" },
            new MyDic() { ID = 2, Name = "Second" },
            new MyDic() { ID = 3, Name = "Third" },
            new MyDic() { ID = 4, Name = "Fourth" },
            new MyDic() { ID = 5, Name = "Fifth" }
        };
        MyModelObject = new MyData() { Name = "First Name", SubName = "Sub Name", DocTypeID = 1 };
    }  
}

我的 XAML 是：

<Window x:Class="TestContentPresenter.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:local="clr-namespace:TestContentPresenter"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <local:MyTemplateSelector x:Key="MyTemplateSelector"/>
        <DataTemplate x:Key="DefaultTemplate">
            <StackPanel Margin="5">
                <TextBlock Text="Empty"/>
            </StackPanel>
        </DataTemplate>

        <DataTemplate x:Key="FirstTemplate">
            <StackPanel Margin="10">
                <TextBox Text="{Binding Name}" FontSize="14" FontWeight="Bold"/>
            </StackPanel>
        </DataTemplate>

        <DataTemplate x:Key="SecondTemplate">
            <StackPanel Margin="20">
                <TextBox Text="{Binding SubName}"/>
            </StackPanel>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <StackPanel>
            <ComboBox ItemsSource="{Binding MyDicList}" DisplayMemberPath="Name" SelectedValuePath="ID" SelectedValue="{Binding SelectedDocTypeID}" Margin="10"/>
            <ContentPresenter Content="{Binding MyModelObject}" ContentTemplateSelector="{StaticResource MyTemplateSelector}" Margin="10"/>
        </StackPanel>
    </Grid>
</Window>

我的 DataTemplateSelector 是：

public class MyTemplateSelector : DataTemplateSelector
    {
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            var defaultTemplate = (container as FrameworkElement).FindResource("DefaultTemplate") as DataTemplate;
            if (item == null || !(item is MyData))
            {
                return defaultTemplate;
            }
            switch ((int?)(item as MyData).DocTypeID)
            {
                case 1:
                    return (container as FrameworkElement).FindResource("FirstTemplate") as DataTemplate;
                case 2:
                    return (container as FrameworkElement).FindResource("SecondTemplate") as DataTemplate;
            }
            return defaultTemplate;
        }
    }

更改ComboBox项时更改内容ContentPresenter

0 个答案: