如何使用 .NET MAUI 建立桌面 BarCode 應用程式（掃描器／生成器）

using IronBarCode;

namespace MauiApp1
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
            // Your license key is set here
            IronBarCode.License.LicenseKey = "YOUR_KEY"
        }

        private async void OnScanButtonClicked(object sender, EventArgs e)
        {
            try
            {
                var fileResult = await MediaPicker.Default.PickPhotoAsync();

                if (fileResult != null)
                {
                    // 1. Copy the file content into a byte array or MemoryStream immediately
                    // This ensures we have the data in memory before the file closes
                    byte[] imageBytes;
                    using (var stream = await fileResult.OpenReadAsync())
                    using (var memoryStream = new MemoryStream())
                    {
                        await stream.CopyToAsync(memoryStream);
                        imageBytes = memoryStream.ToArray();
                    }

                    // 2. Set the Image Source for the UI
                    // We give the UI a FRESH stream from the bytes we just saved
                    ScannerImage.Source = ImageSource.FromStream(() => new MemoryStream(imageBytes));

                    // 3. Process the Barcode
                    // We give IronBarcode its OWN fresh stream from the same bytes
                    using (var processingStream = new MemoryStream(imageBytes))
                    {
                        // 4. Read the barcode with Read
                        var results = BarcodeReader.Read(processingStream);

                        // 5. Display barcode results
                        if (results != null && results.Count > 0)
                        {

                            // Successfully found barcode value
                            ResultLabel.Text = $"Success: {results[0].Value}";
                            ResultLabel.TextColor = Colors.Green;
                        }
                        else
                        {
                            // Image uploaded has no barcode or barcode value is not found
                            ResultLabel.Text = "No barcode detected.";
                            ResultLabel.TextColor = Colors.Red;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                // Display any exception thrown in runtime
                ResultLabel.Text = $"Error: {ex.Message}";
                ResultLabel.TextColor = Colors.Red;
            }
        }
    }
}

Imports IronBarCode

Namespace MauiApp1
    Partial Public Class MainPage
        Inherits ContentPage

        Public Sub New()
            InitializeComponent()
            ' Your license key is set here
            IronBarCode.License.LicenseKey = "YOUR_KEY"
        End Sub

        Private Async Sub OnScanButtonClicked(ByVal sender As Object, ByVal e As EventArgs)
            Try
                Dim fileResult = Await MediaPicker.Default.PickPhotoAsync()

                If fileResult IsNot Nothing Then
                    ' 1. Copy the file content into a byte array or MemoryStream immediately
                    ' This ensures we have the data in memory before the file closes
                    Dim imageBytes As Byte()
                    Using stream = Await fileResult.OpenReadAsync(), memoryStream = New MemoryStream()
                        Await stream.CopyToAsync(memoryStream)
                        imageBytes = memoryStream.ToArray()
                    End Using

                    ' 2. Set the Image Source for the UI
                    ' We give the UI a FRESH stream from the bytes we just saved
                    ScannerImage.Source = ImageSource.FromStream(Function() New MemoryStream(imageBytes))

                    ' 3. Process the Barcode
                    ' We give IronBarcode its OWN fresh stream from the same bytes
                    Using processingStream = New MemoryStream(imageBytes)
                        ' 4. Read the barcode with Read
                        Dim results = BarcodeReader.Read(processingStream)

                        ' 5. Display barcode results
                        If results IsNot Nothing AndAlso results.Count > 0 Then
                            ' Successfully found barcode value
                            ResultLabel.Text = $"Success: {results(0).Value}"
                            ResultLabel.TextColor = Colors.Green
                        Else
                            ' Image uploaded has no barcode or barcode value is not found
                            ResultLabel.Text = "No barcode detected."
                            ResultLabel.TextColor = Colors.Red
                        End If
                    End Using
                End If
            Catch ex As Exception
                ' Display any exception thrown in runtime
                ResultLabel.Text = $"Error: {ex.Message}"
                ResultLabel.TextColor = Colors.Red
            End Try
        End Sub
    End Class
End Namespace

using IronBarCode;
using System.IO; // Required for saving files

namespace MauiApp1
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
            IronBarCode.License.LicenseKey = "YOUR-KEY";

            // Set default selection
            BarcodeTypePicker.SelectedIndex = 0;
        }

        private void OnGenerateButtonClicked(object sender, EventArgs e)
        {
            try
            {
                // 1. Get and Validate Input
                string text = BarcodeEntry.Text;

                if (string.IsNullOrWhiteSpace(text))
                {
                    StatusLabel.Text = "Error: Please enter text.";
                    StatusLabel.TextColor = Colors.Red;
                    return;
                }

                if (BarcodeTypePicker.SelectedIndex == -1)
                {
                    StatusLabel.Text = "Error: Please select a type.";
                    StatusLabel.TextColor = Colors.Red;
                    return;
                }

                // 2. Determine Encoding Type
                string selectedType = BarcodeTypePicker.SelectedItem.ToString();
                BarcodeEncoding encoding = BarcodeEncoding.QRCode;

                switch (selectedType)
                {
                    case "QRCode": encoding = BarcodeEncoding.QRCode; break;
                    case "Code128": encoding = BarcodeEncoding.Code128; break;
                    case "EAN13": encoding = BarcodeEncoding.EAN13; break;
                    case "Code39": encoding = BarcodeEncoding.Code39; break;
                    case "PDF417": encoding = BarcodeEncoding.PDF417; break;
                }

                // 3. Generate Barcode
                var barcode = BarcodeWriter.CreateBarcode(text, encoding);
                barcode.ResizeTo(400, 200); // Optional resizing

                // 4. Convert to Bytes (JPEG)
                var bytes = barcode.ToJpegBinaryData();

                // 5. Update UI
                GeneratedImage.Source = ImageSource.FromStream(() => new MemoryStream(bytes));

                // 6. Save to Desktop automatically
                string desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
                string fileName = $"barcode_{DateTime.Now:yyyyMMdd_HHmmss}.jpg";
                string fullPath = Path.Combine(desktopPath, fileName);

                File.WriteAllBytes(fullPath, bytes);

                // 7. Show Success Message
                StatusLabel.Text = $"Saved to Desktop:\n{fileName}";
                StatusLabel.TextColor = Colors.Green;
            }
            catch (Exception ex)
            {
                StatusLabel.Text = $"Error: {ex.Message}";
                StatusLabel.TextColor = Colors.Red;
            }
        }
    }
}

Imports IronBarCode
Imports System.IO ' Required for saving files

Namespace MauiApp1
    Public Partial Class MainPage
        Inherits ContentPage

        Public Sub New()
            InitializeComponent()
            IronBarCode.License.LicenseKey = "YOUR-KEY"

            ' Set default selection
            BarcodeTypePicker.SelectedIndex = 0
        End Sub

        Private Sub OnGenerateButtonClicked(sender As Object, e As EventArgs)
            Try
                ' 1. Get and Validate Input
                Dim text As String = BarcodeEntry.Text

                If String.IsNullOrWhiteSpace(text) Then
                    StatusLabel.Text = "Error: Please enter text."
                    StatusLabel.TextColor = Colors.Red
                    Return
                End If

                If BarcodeTypePicker.SelectedIndex = -1 Then
                    StatusLabel.Text = "Error: Please select a type."
                    StatusLabel.TextColor = Colors.Red
                    Return
                End If

                ' 2. Determine Encoding Type
                Dim selectedType As String = BarcodeTypePicker.SelectedItem.ToString()
                Dim encoding As BarcodeEncoding = BarcodeEncoding.QRCode

                Select Case selectedType
                    Case "QRCode"
                        encoding = BarcodeEncoding.QRCode
                    Case "Code128"
                        encoding = BarcodeEncoding.Code128
                    Case "EAN13"
                        encoding = BarcodeEncoding.EAN13
                    Case "Code39"
                        encoding = BarcodeEncoding.Code39
                    Case "PDF417"
                        encoding = BarcodeEncoding.PDF417
                End Select

                ' 3. Generate Barcode
                Dim barcode = BarcodeWriter.CreateBarcode(text, encoding)
                barcode.ResizeTo(400, 200) ' Optional resizing

                ' 4. Convert to Bytes (JPEG)
                Dim bytes = barcode.ToJpegBinaryData()

                ' 5. Update UI
                GeneratedImage.Source = ImageSource.FromStream(Function() New MemoryStream(bytes))

                ' 6. Save to Desktop automatically
                Dim desktopPath As String = Environment.GetFolderPath(Environment.SpecialFolder.Desktop)
                Dim fileName As String = $"barcode_{DateTime.Now:yyyyMMdd_HHmmss}.jpg"
                Dim fullPath As String = Path.Combine(desktopPath, fileName)

                File.WriteAllBytes(fullPath, bytes)

                ' 7. Show Success Message
                StatusLabel.Text = $"Saved to Desktop:{Environment.NewLine}{fileName}"
                StatusLabel.TextColor = Colors.Green
            Catch ex As Exception
                StatusLabel.Text = $"Error: {ex.Message}"
                StatusLabel.TextColor = Colors.Red
            End Try
        End Sub
    End Class
End Namespace