Xamarin 表单：加载页面时显示 DISABLE_XAML_GENERATED_BINDING_DEBUG_OUTPUT

Question

在 xamarin UWP 中加载页面时重定向到 App.g.i.cs。代码控制来到下面的if block.

#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 e 上显示 {Windows.UI.Xaml.UnhandledExceptionEventArgs}

我不明白这是什么问题？这与 XAML 中的某些错误有关吗？此问题仅出现在 windows 应用程序上，Android 和 IOS 应用程序部分工作正常。

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

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

我能够在您的 XAML 文件中编译代码和运行应用 after converting your PCL to .net standard 2.0, updating all nuget packages to last version and changing xmlns:controls="clr-namespace:ImageCircle.Forms.Plugin.Abstractions;assembly=ImageCircle.Forms.Plugin.Abstractions" to xmlns:controls="clr-namespace:ImageCircle.Forms.Plugin.Abstractions;assembly=ImageCircle.Forms.Plugin" as stated in the documentation。

单击 ResetPassword 在这一行显示 System.Collections.Generic.KeyNotFoundException：

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

所以改成

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

处理“initialLogin”未添加到 Application.Current.Properties 集合的情况。接下来在使用前检查值是否为 != null。

同样在 Mainpage.xaml.cs 中，您对 username 和 password.

犯了同样的错误

也改

所以重置有效：

Answer 2

真正的问题在于 disaplayalert。

我正在使用以下代码显示警报：

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

如果我像下面这样更改以上几行，就不会出现问题。

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

Xamarin 表单：加载页面时显示 DISABLE_XAML_GENERATED_BINDING_DEBUG_OUTPUT

Xamarin forms: Showing DISABLE_XAML_GENERATED_BINDING_DEBUG_OUTPUT when loading a page

unhandled-exception

xamarin.forms

uwp