名刺用QRコードジェネレーター（初心者ガイド）

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="QR_Code_Business_Card.MainPage"
             Title="vCard QR Generator">
    <Grid Padding="20" RowDefinitions="*,Auto" ColumnDefinitions="*,Auto,*">
        <ScrollView Grid.Column="0">
            <VerticalStackLayout Spacing="15">
                <Entry x:Name="FirstNameEntry" Placeholder="First Name*" />
                <Entry x:Name="LastNameEntry" Placeholder="Last Name*" />
                <Entry x:Name="EmailEntry" Placeholder="Email*" Keyboard="Email" />
                <Entry x:Name="PhoneEntry" Placeholder="Phone*" Keyboard="Telephone" />
                <Entry x:Name="CompanyEntry" Placeholder="Company" />
                <Entry x:Name="TitleEntry" Placeholder="Job Title" />
                <Entry x:Name="WebsiteEntry" Placeholder="Website" Keyboard="Url" />
                <Entry x:Name="AddressEntry" 
           Placeholder="Address"
           Margin="0,0,0,10" />
                <Button x:Name="GenerateButton" 
            Text="Generate QR Code"
            Clicked="OnGenerateButtonClicked"
            HorizontalOptions="Fill"
            BackgroundColor="#8E24AA"
            TextColor="White"
            CornerRadius="5"
            HeightRequest="50"
            Margin="0,10,0,0" />
            </VerticalStackLayout>
        </ScrollView>
        <BoxView Grid.Column="1" WidthRequest="1" Color="LightGray" Margin="10,0" />
        <VerticalStackLayout Grid.Column="2" Spacing="15">
            <Image x:Name="QrCodeImage"
                   HeightRequest="200"
                   WidthRequest="200"
                   Aspect="AspectFit"
                   Source="https://via.placeholder.com/200x200.png?text=QR+Code" />
            <Button x:Name="SaveQRButton" 
                    Text="Save QR Code"
                    Clicked="OnSaveQRButtonClicked"
                    IsEnabled="False"
                    HorizontalOptions="Fill"
                    BackgroundColor="#7B1FA2"
                    TextColor="White" />
        </VerticalStackLayout>
    </Grid>
</ContentPage>

'INSTANT VB TODO TASK: The following line uses invalid syntax:
'<?xml version="1.0" encoding="utf-8" ?> <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:@Class="QR_Code_Business_Card.MainPage" Title="vCard QR Generator"> <Grid Padding="20" RowDefinitions="*,Auto" ColumnDefinitions="*,Auto,*"> <ScrollView Grid.Column="0"> <VerticalStackLayout Spacing="15"> <Entry x:Name="FirstNameEntry" Placeholder="First Name*" /> <Entry x:Name="LastNameEntry" Placeholder="Last Name*" /> <Entry x:Name="EmailEntry" Placeholder="Email*" Keyboard="Email" /> <Entry x:Name="PhoneEntry" Placeholder="Phone*" Keyboard="Telephone" /> <Entry x:Name="CompanyEntry" Placeholder="Company" /> <Entry x:Name="TitleEntry" Placeholder="Job Title" /> <Entry x:Name="WebsiteEntry" Placeholder="Website" Keyboard="Url" /> <Entry x:Name="AddressEntry" Placeholder="Address" Margin="0,0,0,10" /> <Button x:Name="GenerateButton" Text="Generate QR Code" Clicked="OnGenerateButtonClicked" HorizontalOptions="Fill" BackgroundColor="#8E24AA" TextColor="White" CornerRadius="5" HeightRequest="50" Margin="0,10,0,0" /> </VerticalStackLayout> </ScrollView> <BoxView Grid.Column="1" WidthRequest="1" Color="LightGray" Margin="10,0" /> <VerticalStackLayout Grid.Column="2" Spacing="15"> <Image x:Name="QrCodeImage" HeightRequest="200" WidthRequest="200" Aspect="AspectFit" Source="https://via.placeholder.com/200x200.png?text=QR+Code" /> <Button x:Name="SaveQRButton" Text="Save QR Code" Clicked="OnSaveQRButtonClicked" IsEnabled="False" HorizontalOptions="Fill" BackgroundColor="#7B1FA2" TextColor="White" /> </VerticalStackLayout> </Grid> </ContentPage>

using IronQr;
using IronSoftware.Drawing;
using System.Text.RegularExpressions;
namespace QR_Code_Business_Card
{
    public partial class MainPage : ContentPage
    {
        private AnyBitmap qrImage;
        public MainPage()
        {
            License.LicenseKey = "License";
            InitializeComponent();
        }
        private async void OnGenerateButtonClicked(object sender, EventArgs e)
        {
            if (!ValidateInputs())
            {
                await DisplayAlert("Validation Error", "Please fill in all required fields correctly.", "OK");
                return;
            }
            string vCardData = GenerateVCardData();
            // Create a QR Code object
            QrCode myQr = QrWriter.Write(vCardData);
            // Save QR Code as a Bitmap
            qrImage = myQr.Save();
            Display QR Code image
            string tempFileName = Path.Combine(FileSystem.CacheDirectory, "temp_qr.png");
            qrImage.SaveAs(tempFileName);
            QrCodeImage.Source = ImageSource.FromFile(tempFileName);
            SaveQRButton.IsEnabled = true;
            await DisplayAlert("Success", "Generated QR code is ready!", "OK");
        }
        private async void OnSaveQRButtonClicked(object sender, EventArgs e)
        {
            if (qrImage == null)
            {
                await DisplayAlert("Error", "Please generate a QR code first!", "OK");
                return;
            }
            string fileName = Path.Combine(FileSystem.AppDataDirectory, "vcard_qr.png");
            qrImage.SaveAs(fileName);
            await DisplayAlert("Success", $"QR Code saved to {fileName}", "OK");
        }
        private bool ValidateInputs()
        {
            if (string.IsNullOrWhiteSpace(FirstNameEntry.Text) 

                string.IsNullOrWhiteSpace(LastNameEntry.Text) 

                string.IsNullOrWhiteSpace(PhoneEntry.Text))
            {
                return false;
            }
            // Basic email validation
            if (string.IsNullOrWhiteSpace(EmailEntry.Text) 
 !Regex.IsMatch(EmailEntry.Text, @"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$"))
            {
                return false;
            }
            return true;
        }
        private string GenerateVCardData()
        {
            return $@"BEGIN:VCARD
VERSION:3.0
N:{LastNameEntry.Text};{FirstNameEntry.Text}
FN:{FirstNameEntry.Text} {LastNameEntry.Text}
ORG:{CompanyEntry.Text}
TITLE:{TitleEntry.Text}
TEL;TYPE=WORK,VOICE:{PhoneEntry.Text}
EMAIL:{EmailEntry.Text}
URL:{WebsiteEntry.Text}
ADR;TYPE=WORK:;;{AddressEntry.Text}
END:VCARD";
        }
    }
}

Imports IronQr
Imports IronSoftware.Drawing
Imports System.Text.RegularExpressions
Namespace QR_Code_Business_Card
	Partial Public Class MainPage
		Inherits ContentPage

		Private qrImage As AnyBitmap
		Public Sub New()
			License.LicenseKey = "License"
			InitializeComponent()
		End Sub
		Private Async Sub OnGenerateButtonClicked(ByVal sender As Object, ByVal e As EventArgs)
			If Not ValidateInputs() Then
				Await DisplayAlert("Validation Error", "Please fill in all required fields correctly.", "OK")
				Return
			End If
			Dim vCardData As String = GenerateVCardData()
			' Create a QR Code object
			Dim myQr As QrCode = QrWriter.Write(vCardData)
			' Save QR Code as a Bitmap
			qrImage = myQr.Save()
			Display QR Code image String tempFileName = Path.Combine(FileSystem.CacheDirectory, "temp_qr.png")
			qrImage.SaveAs(tempFileName)
			QrCodeImage.Source = ImageSource.FromFile(tempFileName)
			SaveQRButton.IsEnabled = True
			Await DisplayAlert("Success", "Generated QR code is ready!", "OK")
		End Sub
		Private Async Sub OnSaveQRButtonClicked(ByVal sender As Object, ByVal e As EventArgs)
			If qrImage Is Nothing Then
				Await DisplayAlert("Error", "Please generate a QR code first!", "OK")
				Return
			End If
			Dim fileName As String = Path.Combine(FileSystem.AppDataDirectory, "vcard_qr.png")
			qrImage.SaveAs(fileName)
			Await DisplayAlert("Success", $"QR Code saved to {fileName}", "OK")
		End Sub
		Private Function ValidateInputs() As Boolean
			If String.IsNullOrWhiteSpace(FirstNameEntry.Text) String.IsNullOrWhiteSpace(LastNameEntry.Text) String.IsNullOrWhiteSpace(PhoneEntry.Text) Then
				Return False
			End If
			' Basic email validation
			If String.IsNullOrWhiteSpace(EmailEntry.Text) Not Regex.IsMatch(EmailEntry.Text, "^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$") Then
				Return False
			End If
			Return True
		End Function
		Private Function GenerateVCardData() As String
			Return $"BEGIN:VCARD
VERSION:3.0
N:{LastNameEntry.Text};{FirstNameEntry.Text}
FN:{FirstNameEntry.Text} {LastNameEntry.Text}
ORG:{CompanyEntry.Text}
TITLE:{TitleEntry.Text}
TEL;TYPE=WORK,VOICE:{PhoneEntry.Text}
EMAIL:{EmailEntry.Text}
URL:{WebsiteEntry.Text}
ADR;TYPE=WORK:;;{AddressEntry.Text}
END:VCARD"
		End Function
	End Class
End Namespace