如何将ObservableCollection绑定到ListView?

问题描述 投票:0回答:1

我创建了一个ObservableCollection,使用实体框架从数据库中填充ListViev。当我调用fill方法时,我最终无休止地尝试填充集合。我有一个模型Device_compiexity和Device_category,它们与device_complexity_id相关。对于他们,我创建了VievModel,在此基础上我创建了一个填充的集合。

我的ViewModel:

class DeviceCategoryViewModel
{
    TechDContext dc = new TechDContext();
    public int Device_category_id { get; set; }
    public string Сategory_name { get; set; }
    public int Device_complexity_id { get; set; }
    public string Device_complexity_name { get; set; }

    public static DeviceCategoryViewModel DeviceCaterogyVM(DeviceCategory deviceCategory, DeviceComplexity deviceComplexity)
    {
        return new DeviceCategoryViewModel
        {
            Device_category_id = deviceCategory.Device_category_id,
            Сategory_name = deviceCategory.Category_name,
            Device_complexity_id = deviceCategory.Device_complexity_id,
            Device_complexity_name = deviceComplexity.Device_complexity_name,
        };
    }

    public DeviceCategoryViewModel()
    {
        FillDeviceCategories();
    }

    public void FillDeviceCategories()
    {
        using (TechDContext dc = new TechDContext())
        {
            var q = from cat in dc.DeviceCategories
                    join com in dc.DeviceComplexities on cat.Device_complexity_id equals com.Device_complexity_id
                    select new DeviceCategoryViewModel
                    {
                        Device_category_id = cat.Device_category_id,
                        Сategory_name = cat.Category_name,
                        Device_complexity_id = com.Device_complexity_id,
                        Device_complexity_name = com.Device_complexity_name
                    };
            deviceCategories = new ObservableCollection<DeviceCategoryViewModel>(q);
        }

    }

    private ObservableCollection<DeviceCategoryViewModel> deviceCategories;
    public ObservableCollection<DeviceCategoryViewModel> DeviceCategories
    {
        get
        {
            return deviceCategories;
        }
    }

    private static DeviceCategoryViewModel selectedDeviceCategory;
    public DeviceCategoryViewModel SelectedDeviceCategory
    {
        get
        {
            return selectedDeviceCategory;
        }
        set
        {
            selectedDeviceCategory = value;
        }
    }
}

在窗口初始化我做:

DeviceCategoriesPanel.DataContext = new DeviceCategoryViewModel();

在XAML中我这样做:

<Grid HorizontalAlignment="Left" Height="447" x:Name="DeviceCategoriesPanel" Margin="392,2,0,0" VerticalAlignment="Top" Width="392">
                <Label x:Name="label1_Copy2" Content="Категории устройств" HorizontalAlignment="Left" Margin="10,0,0,410" VerticalAlignment="Bottom" FontWeight="Bold" Width="188" FontSize="14"/>
                <ListView x:Name="categoriesComponentsLV" HorizontalAlignment="Right" MaxHeight="200" MinHeight="150"  Margin="0,44,10,0" Grid.Column="0" ItemsSource="{Binding DeviceCategories}" SelectedItem="{Binding SelectedDeviceCategory}" VerticalAlignment="Top" Width="372" Height="197">
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <StackPanel Margin="5">
                                <TextBlock FontSize="18" Text="{Binding Path=Category_name}" />
                                <TextBlock Text="{Binding Path=Device_complexity_name}" />
                            </StackPanel>
                        </DataTemplate>
                    </ListView.ItemTemplate>
                </ListView>
 </Grid>
c# wpf entity-framework data-binding observablecollection
1个回答
0
投票

当您新建每个devicecategoryview模型时:

                select new DeviceCategoryViewModel
                {

它的构造函数将运行。它的构造函数是做什么的?

public DeviceCategoryViewModel()
{
    FillDeviceCategories();
}

那是你的问题。

因为FillDeviceCategories中有linq,它反过来会为它找到的每一个调用FillDeviceCategories ....反过来每次调用FillDevicategories ......可能不完全无穷无尽,因为你最终会堆叠溢出或者令人讨厌的东西。

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