我有一个 xaml，它有一个带有 ListView 和按钮的网格，并且在 编译出现这个错误的时刻: 错误:指定的转换无效。
我认为问题可能出在网格内部的 ListView 中，但我还没有真正找到解决方案
这是我的 xaml:
<?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="FCR.App.Views.AdvanceSearchResultPage" Title="AdvanceSearchResultPage" xmlns:extended="clr-namespace:FCR.App.ExtendedClasses;assembly=FCR.App">
<ContentPage.Padding>
<OnPlatform x:TypeArguments="Thickness" iOS="0, 10, 0, 0" WinPhone="20,20,20,20" />
</ContentPage.Padding>
<ContentPage.Content>
<StackLayout VerticalOptions="StartAndExpand">
<ContentView IsVisible="false" x:Name="TitleHC">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="9.5*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Image Source="blue_circle.png" Grid.Column="0" />
<StackLayout Padding="0,4,0,5" VerticalOptions="Fill" Grid.Column="1">
<Label VerticalOptions="CenterAndExpand" TextColor="#0368b1" Text="Histórico de conéxiones" FontSize="20">
<Label.FontFamily>
<OnPlatform x:TypeArguments="x:String">
<OnPlatform.iOS>FrutigerLTStd-Cn</OnPlatform.iOS>
<OnPlatform.Android>FrutigerLTStd-Cn.otf#FrutigerLTStd-Cn</OnPlatform.Android>
</OnPlatform>
</Label.FontFamily>
</Label>
</StackLayout>
</Grid>
</ContentView>
<ContentView IsVisible="false" x:Name="TitleHM">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="9.5*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Image Source="blue_circle.png" Grid.Column="0" />
<StackLayout Padding="0,4,0,5" VerticalOptions="Fill" Grid.Column="1">
<Label VerticalOptions="CenterAndExpand" TextColor="#0368b1" Text="Histórico de módificaciones" FontSize="20">
<Label.FontFamily>
<OnPlatform x:TypeArguments="x:String">
<OnPlatform.iOS>FrutigerLTStd-Cn</OnPlatform.iOS>
<OnPlatform.Android>FrutigerLTStd-Cn.otf#FrutigerLTStd-Cn</OnPlatform.Android>
</OnPlatform>
</Label.FontFamily>
</Label>
</StackLayout>
</Grid>
</ContentView>
<Grid VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<ContentView x:Name="contentListView" IsVisible="true" Padding="0,10,0,0" BackgroundColor="White" Grid.Row="0">
<ListView x:Name="resultListView" BackgroundColor="White" HasUnevenRows="true" HorizontalOptions="FillAndExpand" SeparatorVisibility="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.View>
<StackLayout BackgroundColor="White" Padding="0" Opacity="90">
<ContentView Padding="1,0,1,1" BackgroundColor="Gray">
<Grid
BackgroundColor="White">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.7*">
</ColumnDefinition>
<ColumnDefinition Width="0.15*">
</ColumnDefinition>
<ColumnDefinition Width="0.15*">
</ColumnDefinition>
</Grid.ColumnDefinitions>
<StackLayout Grid.Column="0">
<Label Margin="-5" Text="{Binding NombreCompleto}" TextColor="Gray" Font="Bold,13" />
<Label Margin="-5"
Text="{Binding OrganizacionMayusculas}" TextColor="Gray" FontSize="13" />
<Label Margin="-5" Text="{Binding Region}" TextColor="Gray" FontSize="13" />
</StackLayout>
<Label Margin="0,0,0,2" Text="Detalle" Grid.Column="1"
Font="Bold, 13" ClassId="{Binding IdContacto}" TextColor="Gray" VerticalOptions="End">
<Label.FontFamily>
<OnPlatform x:TypeArguments="x:String" iOS="8">
<OnPlatform.iOS>FrutigerLTStd-BoldCn</OnPlatform.iOS>
<OnPlatform.Android>FrutigerLTStd-BoldCn.otf#FrutigerLTStd-BoldCn</OnPlatform.Android>
</OnPlatform>
</Label.FontFamily>
<Label.GestureRecognizers>
<TapGestureRecognizer Tapped="OnTapGestureRecognizerDetail" />
</Label.GestureRecognizers>
</Label>
<Label Margin="0,0,0,2" Text="Borrar" Grid.Column="2"
Font="Bold, 13" ClassId="{Binding IdContacto}" TextColor="Gray" VerticalOptions="End">
<Label.FontFamily>
<OnPlatform x:TypeArguments="x:String" iOS="8">
<OnPlatform.iOS>FrutigerLTStd-BoldCn</OnPlatform.iOS>
<OnPlatform.Android>FrutigerLTStd-BoldCn.otf#FrutigerLTStd-BoldCn</OnPlatform.Android>
</OnPlatform>
</Label.FontFamily>
<Label.GestureRecognizers>
<TapGestureRecognizer Tapped="OnTapGestureRecognizerDelete" />
</Label.GestureRecognizers>
</Label>
</Grid>
</ContentView>
</StackLayout>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ContentView>
<StackLayout>
<extended:CustomButton Text="Volver" Grid.Row="1" x:Name="dismissbutton" Clicked="OnDismissButtonClicked" WidthRequest="100" Style="{StaticResource buttonStyle}" />
</StackLayout>
</Grid>
</StackLayout>
</ContentPage.Content>
</ContentPage>
最佳答案
问题
- 通常，您在使用数据绑定(bind)时可能会发现这类错误。当我们尝试将不同类型与一些编译器不完全期望的控件绑定(bind)时。
很少有地方我能发现装订有点奇怪 -
ClassId="{Binding IdContacto}"
我不确定你是否绑定(bind)正确。如果我是你，我会删除所有 ClassId 绑定(bind)，然后继续构建编译过程。
- 此外，我会尝试注释掉
OnPlatform代码并构建/编译/运行项目。
这些是您可以尝试的一些远射。在查看整个 Stacktrace 之后，我们可能能够针对具体问题做出更多诊断。
关于xamarin - 错误 : Specified cast is not valid.，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43880628/