我将一个listview进行了分组,每当我触摸分组标题时,该分组中的所有项目都会隐藏,但是由于某些原因,单元格仍会保留
我试图为ViewCell中的所有元素设置一个绑定的IsVisible属性,但仍然无法使其工作
这里是我的ListView xaml代码:
<ListView x:Name="GroupsList"
ItemsSource="{Binding Dishes}"
IsGroupingEnabled="True"
SeparatorColor="Black"
SeparatorVisibility="Default"
HasUnevenRows="True"
GroupShortNameBinding="{Binding Key}">
<ListView.GroupHeaderTemplate>
<DataTemplate>
<ViewCell Height="50">
<StackLayout
VerticalOptions="FillAndExpand"
BackgroundColor="LightSlateGray">
<Button BackgroundColor="Transparent"
BorderColor="Transparent"
BorderWidth="0"
Text="{Binding Key}"
TextColor="White"
HorizontalOptions="StartAndExpand"
Command="{Binding BindingContext.SelectGroupHeader, Source={x:Reference DishesPage}}"
CommandParameter="{Binding Key}"
ContentLayout="Right, 300"
ImageSource="next_disclosure"></Button>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.GroupHeaderTemplate>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ContentView Padding="2, 5, 5, 0"
IsVisible="{Binding IsVisible}">
<Frame Padding="2"
HasShadow="False"
BackgroundColor="White">
<StackLayout Orientation="Horizontal">
<Label Margin="10"
Text="{Binding Name}"
TextColor="Black"
FontSize="Medium"
HorizontalOptions="StartAndExpand"></Label>
</StackLayout>
</Frame>
</ContentView>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
这是我的ViewModel代码:
private async Task SelectedGroupHeader(string item)
{
foreach(var group in Dishes)
{
if(item == group.Key)
{
foreach(var dish in group)
{
if (dish.IsVisible)
{
dish.IsVisible = false;
}
else
{
dish.IsVisible = true;
}
}
}
}
}
答案 0 :(得分:1)
问题在于,您要隐藏项时将ContentView.IsVisible
设置为false
,但是当您隐藏ContentView
和项目仍保留在列表中,因此您仍然可以看到这些项目,但没有ContentView
(空白)!
我发现可以实现目标的一种方法是将被点击的组的项目存储在某处,并在点击时清除其内容。执行此操作后,该组将变为空,因此ListView
中的项目将不再可见。当您再次点击组标题时,您会再次向该组添加项目,以便ListView
再次显示您的项目。
我正在工作的代码大致如下:
在 XAML 中,我仅删除了与ContentView.IsVisible
的绑定:
<ListView x:Name="GroupsList"
ItemsSource="{Binding Dishes}"
IsGroupingEnabled="True"
SeparatorColor="Black"
SeparatorVisibility="Default"
HasUnevenRows="True"
GroupShortNameBinding="{Binding Key}">
<ListView.GroupHeaderTemplate>
<DataTemplate>
<ViewCell Height="50">
<StackLayout
VerticalOptions="FillAndExpand"
BackgroundColor="LightSlateGray">
<Button BackgroundColor="Transparent"
BorderColor="Transparent"
BorderWidth="0"
Text="{Binding Key}"
TextColor="White"
HorizontalOptions="StartAndExpand"
Command="{Binding BindingContext.SelectGroupHeader, Source={x:Reference DishesPage}}"
CommandParameter="{Binding Key}"
ContentLayout="Right, 300"
ImageSource="next_disclosure"></Button>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.GroupHeaderTemplate>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ContentView Padding="2, 5, 5, 0">
<Frame Padding="2"
HasShadow="False"
BackgroundColor="White">
<StackLayout Orientation="Horizontal">
<Label Margin="10"
Text="{Binding Name}"
TextColor="Black"
FontSize="Medium"
HorizontalOptions="StartAndExpand"></Label>
</StackLayout>
</Frame>
</ContentView>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
在您的 ViewModel 中,您必须执行以下操作:
private async Task SelectedGroupHeader(string item)
{
foreach(var group in Dishes)
{
if(item == group.Key)
{
if(!group.IsHidden)
{
group.Clear();
group.IsHidden = true; // This is simply a flag you can set in your group class to keep track of if the group is collapsed or not
}
else
{
AddItemsToGroup(group)// Add this group all the elements that belongs to it.
group.IsHidden = false;
}
}
}
}
我希望这会有所帮助!
注意:仅当您的项目集合为ObservableCollection
时,此方法才有效,以便在集合更改时通知ListView
!