Ui 没有实时更新
Ui is not updating on realtime
我有一个列表视图,用于显示我从 api.i 获得的所有项目有一个实时事件,它将修改 observablecollection 类型的项目中的一个字段
<?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,但只更新了用户滚动上的 UI。这是我的视图模型
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
- CachingStrategy="RecycleElement" 我删除了这个,它也不会随着滚动更新
- INotifyPropertyChanged 有任何问题,我试图从列表中删除一个项目,它正在工作并更新 ui.i 想更新项目内的字段
谁能帮帮我
从评论中推断,您还需要在 Job
对象上实现 INotifyPropertyChanged
接口。使用 ObservableCollection
仅有助于该集合中的更改,因此当您删除或添加 Job
对象时,如果 inside Job
中的某些内容发生更改则不会对象。
因此,在您的 Job
对象中执行此操作(根据您发布的代码进行逆向工程):
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));
}
}
您可以从 JobViewModel
中删除 INotifyPropertyChanged
,但有时您可能也需要它
我有一个列表视图,用于显示我从 api.i 获得的所有项目有一个实时事件,它将修改 observablecollection 类型的项目中的一个字段
<?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,但只更新了用户滚动上的 UI。这是我的视图模型
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
- CachingStrategy="RecycleElement" 我删除了这个,它也不会随着滚动更新
- INotifyPropertyChanged 有任何问题,我试图从列表中删除一个项目,它正在工作并更新 ui.i 想更新项目内的字段 谁能帮帮我
从评论中推断,您还需要在 Job
对象上实现 INotifyPropertyChanged
接口。使用 ObservableCollection
仅有助于该集合中的更改,因此当您删除或添加 Job
对象时,如果 inside Job
中的某些内容发生更改则不会对象。
因此,在您的 Job
对象中执行此操作(根据您发布的代码进行逆向工程):
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));
}
}
您可以从 JobViewModel
中删除 INotifyPropertyChanged
,但有时您可能也需要它