这是我的模特
public class WorkOrder: BaseViewModel
{
public int WorkOrderKey { get; set; }
public int? SiteFk { get; set; }
public int? PMTaskFK { get; set; }
public string PMTaskID { get; set; }
public string WProgress { get; set; }
public string ProblemDescription { get; set; }
public string WorkOrderID { get; set; }
public string Action { get; set; }
public string ExtraAction { get; set; }
public bool JobComplete { get; set; }
public int eWorkProgress { get; set; }
public int eWorkOrderClass { get; set; }
public string TaskItems { get; set; }
public string ProviderUserKey { get; set; }
public string WorkTradeDesc { get; set; }
public int AssetFK { get; set; }
public string AssetID { get; set; }
public string AssetDesc { get; set; }
public int AssetDepartmentFK { get; set; }
public string AssetDepartmentID { get; set; }
public int LocationFK { get; set; }
public string LocationID { get; set; }
public int ParentLocationFK { get; set; }
public string ParentLocationID { get; set; }
public string StartDate { get; set; }
public string DownloadedDescription { get; set; }
public string curUser { get; set; }
public List<Asset> AssetList { get; set; }
private Asset asset1;
public Asset Asset1
{
get { return AssetList!=null? AssetList[0] !=null ? AssetList[0]: null : null ; }
set { SetProperty(ref asset1, value); }
}
private Asset asset2;
public Asset Asset2
{
get { return AssetList != null ? AssetList[1] != null ? AssetList[1] : null : null; }
set { SetProperty(ref asset2, value); }
}
private Asset asset3;
public Asset Asset3
{
get { return AssetList != null ? AssetList[2] != null ? AssetList[2] : null : null; }
set { SetProperty(ref asset3, value); }
}
private bool isSelected;
public bool IsSelected
{
get { return isSelected; }
set { SetProperty(ref isSelected, value); }
}
//public bool IsSelected { get; set; }
}
public class Asset
{
public int Key { get; set; }
public string Id { get; set; }
public string Description { get; set; }
public string Location { get; set; }
public int DepartmentFK { get; set; }
public string DepartmentID { get; set; }
public int LocationFK { get; set; }
public string LocationID { get; set; }
public int ParentLocationFK { get; set; }
public string ParentLocationID { get; set; }
}
这是我的xaml页面，其中我有listview绑定上述模型列表的数据
<ListView Grid.Row="1" x:Name="listWorkOrder" ItemsSource="{Binding ListWorkOrder}" HasUnevenRows="True" SeparatorVisibility="None"
BackgroundColor="Transparent" VerticalOptions="FillAndExpand" CachingStrategy="RetainElement >
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid Margin="0,10,0,0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<controls:CustomCheckbox2 Grid.Column="0" Grid.Row="0" Grid.RowSpan="3" Checked="{Binding IsSelected}" x:Name="chkSelectAll" VerticalOptions="CenterAndExpand" Margin="0" HorizontalOptions="End" />
<!--<Image Grid.Column="0" Grid.Row="0" Grid.RowSpan="3" Source="uncheck.png" VerticalOptions="Center"></Image>-->
<StackLayout Grid.Column="1" Grid.Row="0" Orientation="Horizontal">
<Label Text="Work Order Id:" FontAttributes="Bold"></Label>
<Label Text="{Binding WorkOrderID}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
</StackLayout>
<Frame Margin="10,5,10,5" Grid.Column="1" Grid.Row="1" Padding="10" CornerRadius="0" BackgroundColor="White" OutlineColor="Transparent" VerticalOptions="FillAndExpand">
<Frame.HasShadow>
<OnPlatform x:TypeArguments="x:Boolean">
<On Platform="iOS">False</On>
<On Platform="Android">True</On>
</OnPlatform>
</Frame.HasShadow>
<Grid RowSpacing="10">
<Grid.RowDefinitions >
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Grid Grid.Row="0" RowSpacing="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Label Grid.Column="0" Text="Asset ID :" FontAttributes="Bold" LineBreakMode="NoWrap"></Label>
<Label Grid.Column="1" Text="{Binding Asset1.Id}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
<Label Grid.Column="0" Grid.Row="1" Text="Description :" FontAttributes="Bold" LineBreakMode="NoWrap"></Label>
<Label Grid.Column="1" Grid.Row="1" Text="{Binding Asset1.Description}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
</Grid>
<Grid Grid.Row="1" RowSpacing="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Label Grid.Column="0" Text="Asset ID :" FontAttributes="Bold" LineBreakMode="NoWrap"></Label>
<Label Grid.Column="1" Text="{Binding Asset2.Id}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
<Label Grid.Column="0" Grid.Row="1" Text="Description :" FontAttributes="Bold" LineBreakMode="NoWrap"></Label>
<Label Grid.Column="1" Grid.Row="1" Text="{Binding Asset2.Description}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
</Grid>
<Grid Grid.Row="2" RowSpacing="0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<Label Grid.Column="0" Text="Asset ID :" FontAttributes="Bold" LineBreakMode="NoWrap"></Label>
<Label Grid.Column="1" Text="{Binding Asset3.Id}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
<Label Grid.Column="0" Grid.Row="1" Text="Description :" FontAttributes="Bold" LineBreakMode="NoWrap"></Label>
<Label Grid.Column="1" Grid.Row="1" Text="{Binding Asset3.Description}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
</Grid>
</Grid>
</Frame>
<StackLayout Grid.Column="1" Grid.Row="2" Spacing="0">
<StackLayout Orientation="Horizontal">
<Label Text="PM Task Id:" FontAttributes="Bold"></Label>
<Label Text="{Binding PMTaskID}" HorizontalOptions="StartAndExpand" VerticalOptions="Center"
LineBreakMode="WordWrap" />
</StackLayout>
<Button BackgroundColor="Green" Text="VIEW PM TASK ITEMS" HorizontalOptions="Start"></Button>
</StackLayout>
<BoxView Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" BackgroundColor="Gray" HeightRequest="1"></BoxView>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
<!--<x:Arguments>
<ListViewCachingStrategy>
<OnPlatform x:TypeArguments="ListViewCachingStrategy" iOS="RecycleElement" Android="RetainElement" WinPhone="RecycleElement" />
</ListViewCachingStrategy>
</x:Arguments>-->
</ListView>
我的数据完美绑定。但是当我滚动listview直到结束应用程序崩溃。
谁有想法？我有什么不对的。答案 0 :(得分：2)
Property Asset3可能存在异常，Asset2使用正确的空值处理或检查项目计数。
例如，如果列表AssetList中只有一个项目，那么您将获得例外OutOfRangeException
解决方案，例如：
public Asset Asset1
{
get { return AssetList != null ? AssetList.Count >=0 ? AssetList[0] : null : null;
}