鉴于以下内容ListView，我想要一个命令将单击的对象（在本例中为地址）发送回视图模型中的命令 -SelectNewAddress或DeleteAddress.
<StackLayout VerticalOptions="FillAndExpand" Padding="10,15,10,15">
<Label Text="Addresses" FontSize="22" HorizontalTextAlignment="Center" FontAttributes="Bold" Padding="0,0,0,7" TextColor="#404040" />
<StackLayout VerticalOptions="FillAndExpand">
<flv:FlowListView FlowColumnCount="1"
HeightRequest="200"
SeparatorVisibility="None"
HasUnevenRows="True"
FlowItemsSource="{Binding AllAddresses}">
<flv:FlowListView.FlowColumnTemplate>
<DataTemplate x:DataType="popups:AddressItem">
<Grid ColumnDefinitions="*,35" Padding="0,0,0,15" x:Name="Item">
<Grid Grid.Column="0">
<Grid.GestureRecognizers>
<TapGestureRecognizer
Command="{Binding SelectNewAddress}" />
</Grid.GestureRecognizers>
<Label Text="{Binding MainAddress}"
LineBreakMode="TailTruncation"
HorizontalTextAlignment="Start"
VerticalTextAlignment="Center"
FontSize="18"
TextColor="{StaticResource CommonBlack}"/>
</Grid>
<Grid Grid.Column="1" IsVisible="{Binding IsSelected}" >
<Grid.GestureRecognizers>
<TapGestureRecognizer
Command="{Binding SelectNewAddress}"/>
</Grid.GestureRecognizers>
<StackLayout Padding="10,0,0,0">
<flex:FlexButton Icon="check.png"
WidthRequest="25"
HeightRequest="25"
CornerRadius="18"
BackgroundColor="{StaticResource Primary}"
ForegroundColor="{StaticResource CommonWhite}"
HighlightBackgroundColor="{StaticResource PrimaryDark}"
HighlightForegroundColor="{StaticResource CommonWhite}"/>
</StackLayout>
</Grid>
<Grid Grid.Column="1" IsVisible="{Binding IsSelected, Converter={StaticResource invertBoolConverter}}">
<Grid.GestureRecognizers>
<TapGestureRecognizer Command="{Binding DeleteAddress} />
</Grid.GestureRecognizers>
<StackLayout Padding="10,0,0,0">
<flex:FlexButton Icon="deleteCard.png"
WidthRequest="25"
HeightRequest="25"
CornerRadius="18"
BackgroundColor="{StaticResource WooopDarkGray}"
ForegroundColor="{StaticResource CommonWhite}"
HighlightBackgroundColor="{StaticResource PrimaryDark}"
HighlightForegroundColor="{StaticResource CommonWhite}"/>
</StackLayout>
</Grid>
</Grid>
</DataTemplate>
</flv:FlowListView.FlowColumnTemplate>
</flv:FlowListView>
</StackLayout>
视图模型中的命令如下：
...
public ICommand SelectNewAddress { get; set; }
public ICommand DeleteAddress { get; set; }
...
public AddressSelectionViewModel()
{
DeleteAddress = new Command(DeleteAddressCommand);
SelectNewAddress = new Command(SelectNewAddressCommand);
}
...
private void SelectNewAddressCommand(object obj)
{
try
{
var item = (AddressItem)obj;
AddressHelper.UpdateAddress(item.DeliveryAddressLocation);
UpdateAddresses();
}
catch (Exception ex)
{
// TODO
}
}
private void DeleteAddressCommand(object obj)
{
try
{
var item = (AddressItem)obj;
AddressHelper.RemoveAddress(item.DeliveryAddressLocation);
UpdateAddresses();
}
catch (Exception ex)
{
// TODO
}
}
我希望object obj传递给SelectNewAddressCommand并DeleteAddressCommand成为点击的地址ListView
首先确保您已将您的视图模型包含DataType在Class以下内容中ContentPage：
xmlns:pages="clr-namespace:your.namespace.ViewModels"
x:DataType="pages:AddressSelectionViewModel"
x:Class="your.namespace.Views.AddressSelectionPage"
<ContentPage xmlns="..."
xmlns:x="..."
xmlns:flv="..."
xmlns:popups="..."
xmlns:flex="..."
xmlns:views="..."
xmlns:xct="..."
xmlns:pages="clr-namespace:your.namespace.ViewModels"
x:DataType="pages:AddressSelectionViewModel"
x:Class="your.namespace.Views.AddressSelectionPage"
Shell.FlyoutItemIsVisible="..."
Shell.NavBarIsVisible="..."
Shell.TabBarIsVisible="...">
在顶部Grid元素内部添加属性x:Name="Item"（“Item”仅用作示例，您可以将其命名为任何名称）：
<flv:FlowListView FlowColumnCount="1"
HeightRequest="200"
SeparatorVisibility="None"
HasUnevenRows="True"
FlowItemsSource="{Binding AllAddresses}">
<flv:FlowListView.FlowColumnTemplate>
<DataTemplate x:DataType="popups:AddressItem">
<Grid ColumnDefinitions="*,35" Padding="0,0,0,15" x:Name="Item"> <!-- Here -->
然后我们将Commandand更改CommandParameter为TapGestureRecognizer以下内容：
<TapGestureRecognizer
Command="{Binding Path=SelectNewAddress, Source={RelativeSource AncestorType={x:Type pages:AddressSelectionViewModel}}}"
CommandParameter="{Binding Source={x:Reference Item}, Path=BindingContext}" />
<TapGestureRecognizer
Command="{Binding Path=DeleteAddress, Source={RelativeSource AncestorType={x:Type pages:AddressSelectionViewModel}}}"
CommandParameter="{Binding Source={x:Reference Item}, Path=BindingContext}" />
在Command我们将函数指定为Path，然后我们通过 阐明这个函数的来源是在视图模型内部AncestoryType。当在列表视图中时，我们不能引用被迭代对象之外的属性。因此，我们需要指定所需的来源。
所以现在我们正在引用实际的函数。但是我们还没有发送object obj作为参数。
在 中，我们必须用和CommandParameter传递当前绑定的对象。请注意，在 Source 中，我们引用的名称是我们之前定义的。PathSourceItemx:NameGrid
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