我有一个 ListView ，用于显示我从 api 获得的所有项目。我有一个实时事件，它将修改 observablecollection 类型的项目内的一个字段
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="Dyocense.Views.ManageJobs"
Title="All jobs">
<ContentPage.ToolbarItems>
<ToolbarItem Text="ADD" Clicked="AddJob"></ToolbarItem>
</ContentPage.ToolbarItems>
<ContentPage.Content>
<StackLayout>
<SearchBar x:Name="Search" SearchButtonPressed="SearchBar_SearchButtonPressed"></SearchBar>
<ListView x:Name="JobsListView"
ItemsSource="{Binding Items}"
VerticalOptions="FillAndExpand"
HasUnevenRows="true"
CachingStrategy="RecycleElement"
ItemAppearing="BrowseJobList_ItemAppearing"
IsPullToRefreshEnabled="true"
>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="10">
<Frame HasShadow="True" >
<StackLayout>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label Text="{Binding Name}"
Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="3"
FontSize="Medium"
FontAttributes="Bold"/>
<Label Text="Status"
Grid.Row="1" Grid.Column="0"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding Status}"
Grid.Row="1" Grid.Column="1"
FontSize="16"/>
<Label Text="Goal"
Grid.Row="2" Grid.Column="1"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding Goal}"
Grid.Row="2" Grid.Column="2"
FontSize="16" />
<Label Text="Part"
Grid.Row="3" Grid.Column="1"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding PartName}"
Grid.Row="3" Grid.Column="2"
FontSize="16" />
<Label Text="Assembly"
Grid.Row="4" Grid.Column="1"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding NodeName}"
Grid.Row="4" Grid.Column="2"
FontSize="16" />
<Label Text="GoodCount"
Grid.Row="5" Grid.Column="0"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding GoodCount}"
Grid.Row="6" Grid.Column="0"
FontSize="16"
HorizontalTextAlignment="Center"/>
<Label Text="RejectCount"
Grid.Row="5" Grid.Column="1"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding RejectCount}"
Grid.Row="6" Grid.Column="1"
FontSize="16"
HorizontalTextAlignment="Center"/>
<Label Text="DownTimeCount"
Grid.Row="5" Grid.Column="2"
FontSize="16"
FontAttributes="Bold"/>
<Label Text="{Binding DownTimeCount}"
Grid.Row="6" Grid.Column="2"
FontSize="16"
HorizontalTextAlignment="Center"/>
</Grid>
</StackLayout>
</Frame>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
<ListView.Footer>
<Grid Padding="6" IsVisible="{Binding IsBusy}">
<!--set the footer to have a zero height when invisible-->
<Grid.Triggers>
<Trigger TargetType="Grid" Property="IsVisible" Value="False">
<Setter Property="HeightRequest" Value="0" />
</Trigger>
</Grid.Triggers>
<!--the loading content-->
<Label Text="Loading..." VerticalOptions="Center" HorizontalOptions="Center" />
</Grid>
</ListView.Footer>
</ListView>
</StackLayout>
</ContentPage.Content>
</ContentPage>
我想实时更新好计数。我调试了它在我的列表中更新的代码，但只在用户滚动时更新了 UI。这是我的 View 模型
public class JobViewModel: INotifyPropertyChanged
{
private ObservableCollection<Job> items;
public event PropertyChangedEventHandler PropertyChanged;
public ObservableCollection<Job> Items
{
get { return items; }
set
{
items = value;
if (items != value)
{
items = value;
OnPropertyChanged(nameof(Items));
}
}
}
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
private void updateJoblistOnEvent(NotificationEntity message)
{
var jobId = message.JobId;
Job job = Items.FirstOrDefault(a => a.JobId.Equals(jobId));
switch (message.EventCode)
{
case MessageTypeEnum.Pulse: //Pulse
job.GoodCount = job.GoodCount + 1;
//job.Status = 'Running';
break;
default:
break;
}
}
我怀疑两件事
谁能帮帮我
最佳答案
从评论中推断，您还需要实现 INotifyPropertyChanged Job上的界面目的。使用 ObservableCollection仅有助于该集合中的更改，因此当您删除或添加 Job 时对象，如果 Job 内部发生变化，则不会目的。
所以，在你的 Job对象执行此操作(从您发布的代码逆向工程):
public class Job : INotifyPropertyChanged
{
private int goodCount;
public int GoodCount
{
get { return goodCount; }
set
{
if (goodCount != value)
{
goodCount = value;
OnPropertyChanged(nameof(GoodCount));
}
}
}
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
您可以删除
INotifyPropertyChanged来自您的JobViewModel ，但你可能在某个时候也需要它
关于xaml - ui没有实时更新，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54361148/