Question

在xamarin UWP中加载页面时重定向到App.g.i.cs。代码控制来自以下if块。

#if DEBUG && !DISABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION
        UnhandledException += (sender, e) =>
        {
            if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break();
        };
#endif

如果我将鼠标悬停在显示{Windows.UI.Xaml.UnhandledExceptionEventArgs}的 e 上

我不明白这是什么问题？这与XAML中的某些错误有关吗？仅在Windows应用程序上存在此问题，Android和IOS应用程序部分运行正常。

XAML页面代码：

<?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="Myproject.Pages.CodeValidationPage"
             BackgroundColor="#00aff0">

<ScrollView>
    <StackLayout
        VerticalOptions="FillAndExpand">
        <StackLayout 
        VerticalOptions="CenterAndExpand"
        Orientation="Vertical">

            <Image 
            Source="splash.png"
            HeightRequest="120"
            WidthRequest="120"
            IsVisible="True"
            HorizontalOptions="Center"
            VerticalOptions="CenterAndExpand"/>

            <Label
            Text=" Please check your email for the verification code and activate your account. "
            HorizontalOptions="CenterAndExpand"
                x:Name="italic_test"
            HorizontalTextAlignment="Center"
            Margin="3"
            Font="Italic,15"
            TextColor="White"/>

            <Frame
                HorizontalOptions="FillAndExpand"
                CornerRadius="10"
                Margin="20"
                Padding="0">

                <StackLayout 
                    BackgroundColor="White" 
                    Orientation="Vertical"
                    VerticalOptions="CenterAndExpand" >

                    <Entry 
                        x:Name="codeentry" 
                        Margin="10,10,10,0"
                        Keyboard="Numeric"
                        Placeholder="Enter Verification Code"/>

                    <Entry 
                        x:Name="passwordentry" 
                        Placeholder="Password" 
                        IsVisible="False"
                        Margin="10,10,10,0"
                        IsPassword="True"/>

                    <Entry 
                        x:Name="confirmpasswordentry" 
                        Margin="10,0,10,-10"
                        IsVisible="False"
                        Placeholder="Confirm Password"
                        IsPassword="True"/>

                    <Button
                        Text="Verify Code" 
                        HeightRequest="40"
                        WidthRequest="150"
                        x:Name="validationButton"
                        TextColor="White"
                        HorizontalOptions="CenterAndExpand"
                        Font="Bold,15"
                        Margin="5,15,5,10"
                        BorderRadius="20"
                        BackgroundColor="#00aff0" 
                        Clicked="SaveNewPassword"/>
                </StackLayout>
            </Frame>
        </StackLayout>

        <Label
            VerticalOptions="EndAndExpand"
            HorizontalOptions="CenterAndExpand"
            Margin="0,0,0,15"
                x:Name="backto_label"
                TextColor="White"
                Font="Bold,16"
                Text=" Back to Sign Up "/>
    </StackLayout>
</ScrollView>
</ContentPage>

Answer 1

使用Xamarin.forms 3.x Microsoft moved to .net standard 2.0。

我能够编译代码并运行应用程序after converting your PCL to .net standard 2.0，将所有nuget软件包更新为最新版本，并将XAML文件中的xmlns:controls="clr-namespace:ImageCircle.Forms.Plugin.Abstractions;assembly=ImageCircle.Forms.Plugin.Abstractions"更改为stated in the documentation的xmlns:controls="clr-namespace:ImageCircle.Forms.Plugin.Abstractions;assembly=ImageCircle.Forms.Plugin"

单击ResetPassword在此行显示System.Collections.Generic.KeyNotFoundException：

string initialLogin = Application.Current.Properties["initialLogin"].ToString();

因此将其更改为

Application.Current.Properties.TryGetValue("initialLogin", out var initialLogin);

处理未将“ initialLogin ”添加到Application.Current.Properties集合的情况。接下来，请在使用前检查其值为!= null。

在Mainpage.xaml.cs中，您也用用户名和密码犯了同样的错误。

还要更改PDB type from full to pdb-only to allow debugging. This is a known issue.

所以重置有效：

Answer 2

真正的问题在于disaplayalert。

我将以下代码用于显示警报：

await DisplayAlert("Alert", "A verification code has been sent to your email.", "OK");

如果我像下面那样更改以上行，则不会出现任何问题。

Device.BeginInvokeOnMainThread(async () => 
{
    await DisplayAlert("Alert", "A verification code has been sent to your email.", "OK");
});

Xamarin形式：加载页面时显示DISABLE_XAML_GENERATED_BINDING_DEBUG_OUTPUT

2 个答案: