Question

<StackLayout BackgroundColor="White">
    <ListView x:Name="ListViewMenu" ItemsSource="{Binding Menus}"
          HasUnevenRows="True"
          BackgroundColor="White"
          SeparatorVisibility="None"
          VerticalOptions="FillAndExpand"
          ItemTapped="Handle_ItemTapped"
          ItemSelected="Handle_ItemSelected"
          IsGroupingEnabled = "true"
          SeparatorColor="White">
        <ListView.GroupHeaderTemplate>
            <DataTemplate>
                <ViewCell>
                    <ViewCell.View>
                        <StackLayout BackgroundColor="LightSkyBlue" HeightRequest="25">
                            <Label Text="{Binding Key}"  FontAttributes="Bold"  LineBreakMode="NoWrap" Margin="10,0,0,0">
                                <Label.FontSize>
                                    <OnPlatform x:TypeArguments="x:Double">
                                        <On Platform="Android" Value="20"/>
                                        <On Platform="iOS" Value="20"/>
                                    </OnPlatform>
                                </Label.FontSize>
                            </Label>
                            <StackLayout.VerticalOptions>
                                <OnPlatform x:TypeArguments="LayoutOptions">
                                    <On Platform="Android" Value="Center"/>
                                    <On Platform="iOS" Value="Center"/>
                                </OnPlatform>
                            </StackLayout.VerticalOptions>
                        </StackLayout>
                    </ViewCell.View>
                </ViewCell>
            </DataTemplate>
        </ListView.GroupHeaderTemplate>
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                    <ViewCell.View>
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"></RowDefinition>
                                <RowDefinition Height="Auto"></RowDefinition>
                            </Grid.RowDefinitions>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="6*"></ColumnDefinition>
                                <ColumnDefinition Width="Auto"></ColumnDefinition>
                            </Grid.ColumnDefinitions>
                            <Label Text="{Binding article_description}"
                                       FontAttributes="Bold" FontSize="13"  Margin="10,5,0,-6" Grid.Row="0" LineBreakMode="NoWrap"/>
                            <Label Text="{Binding dish_name}" 
                                   FontSize="13" Margin="10,0,0,2" Grid.Row="1" Grid.Column="0"/>
                            <Label Grid.Row="0" Grid.Column="0" x:Name="LabelReserved"  Text="{Binding reserved}" IsVisible="false" LineBreakMode="NoWrap"/> 
                            <Switch Grid.Row="0" Grid.RowSpan="2" Grid.Column="1"  HorizontalOptions="Start" VerticalOptions="Center" IsEnabled="False" Toggled="SwitchMenu_OnToggled" >
                                <Switch.Triggers>
                                    <DataTrigger TargetType="Switch" Binding="{Binding Source={x:Reference LabelReserved},
                                   Path=Text.Length}" Value="7">
                                        <Setter Property="IsToggled" Value="true" />
                                    </DataTrigger>
                                </Switch.Triggers>
                            </Switch>
                        </Grid>
                    </ViewCell.View>
                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</StackLayout>

菜单模型，这是我设置菜单的方式：

public class Menu
{
    public string day { get; set; }
    public string article_description { get; set; }
    public string Date { get; set; }
    public string dish_name { get; set; }
    public string Reserved { get; set; }
    public string Meal { get; set; }
};

我如何实施groupHeader：

首先，我将所有菜单都放在名为GetGroupedViewMenu的列表中。

然后我按星期几组织菜单：

var menus1 = GetGroupedViewMenu.Where(a => a.day == day).ToList();

之后我按照article_description订购列表：

var newList = menus1.OrderBy(m => m.article_description).ToList();

然后我实现了groupHeader：

var sorted = from menu in newList
                     group menu by menu.Meal into menuGroup
            select new Grouping<string, Models.Menu>(menuGroup.Key, menuGroup);

        Menus = new ObservableCollection<Grouping<string, Models.Menu>>(sorted);

我想要做的是当我点击开关时，我想从列表视图中获取信息和标题（密钥），该视图位于交换机的同一行。我还想将信息输入到后面的代码中的变量中，这样我就可以使用数据将数据插入到数据库中。我怎么能这样做？

Answer 1

这里有几个解决方案：

最简单但最丑陋的方法，找到switch的父级和BindingContext

private void Switch_Toggled(object sender, ToggledEventArgs e)
{
    Switch sw = sender as Switch;
    ViewCell cell = sw.Parent.Parent as ViewCell;
    object obj = cell.BindingContext;

    //do the db action
}

使用BindableProperty

SubClass：

public class MySwitch : Switch
{
    public static readonly BindableProperty ConfigurationItemProperty =
        BindableProperty.Create(propertyName: "ConfigurationItem", returnType: typeof(Item), declaringType: typeof(Switch), defaultValue: null);
    public Item ConfigurationItem { //Item is the class contained in your list.
        get{ return (Item)GetValue(ConfigurationItemProperty);}
        set { SetValue(ConfigurationItemProperty, value); }
    }
}

XMAL：

<ViewCell.View>
    <StackLayout>
        <local:MySwitch  ConfigurationItem ="{Binding}"  Toggled="Switch_Toggled" />
    </StackLayout>
</ViewCell.View>

代码背后：

private void Switch_Toggled(object sender, ToggledEventArgs e)
{
    MySwitch sw = sender as MySwitch;
    Item item = sw.ConfigurationItem;
    //do the db action
}

PS：我在开始时尝试了什么

我发现在ClassId中定义了Element（BindableProperty），我最初的想法是在viewModel中添加一个索引属性，用ClassId绑定它，我可以把它想出来代码，但没有运气它不起作用，索引总是为空。

<Switch  ClassId="{Binding index}" Toggled="Switch_Toggled" />

private void Switch_Toggled(object sender, ToggledEventArgs e)
{
    Switch sw = sender as Switch;
    string index= sw.ClassId;
    //do the db action
}

使用ListView中的数据插入数据库

1 个答案:

PS：我在开始时尝试了什么