How to Build a .NET MAUI Document Scanner App with Capture, Normalize, and Share

Mar 25, 2026

.NET MAUI simplifies cross-platform app development by enabling a single codebase for multiple platforms. The Dynamsoft Capture Vision MAUI Bundle offers powerful APIs for document scanning, barcode reading, and MRZ recognition. In this tutorial, you’ll learn how to create a .NET MAUI document scanner that can capture, normalize, and share documents on both Android and iOS platforms. What you’ll build: A cross-platform .NET MAUI document scanner app that uses the Dynamsoft Capture Vision SDK to detect document edges via camera, normalize the captured image, and share the result to other apps on Android and iOS.

Key Takeaways

The Dynamsoft Capture Vision MAUI Bundle provides a CameraView control and NormalizedImagesResult callback that handle real-time document edge detection and perspective correction in a .NET MAUI app.
Document normalization supports grayscale, color, and binary output modes through EnumImageColourMode, letting you optimize scanned output for different use cases.
The same C# codebase runs on both Android and iOS — only platform-specific provisioning (Xcode signing, Android SDK) differs.
Sharing the normalized document image uses the built-in .NET MAUI Share.RequestAsync API with a temporary cached file.

Common Developer Questions

How do I build a document scanner app in .NET MAUI with real-time edge detection?
How do I normalize and share a captured document image in .NET MAUI on Android and iOS?
What SDK can I use for document scanning and perspective correction in a cross-platform .NET MAUI app?

This article is Part 2 in a 5-Part Series.

.NET MAUI Document Scanner Demo Video

Prerequisites

To get started, ensure you have the following tools installed:

Get a 30-day free trial license for Dynamsoft Capture Vision
Xcode
Android Studio
Visual Studio for Windows or Visual Studio Code for macOS with the .NET MAUI extension
Provisioning Profile for iOS (required if building a .NET MAUI app with Visual Studio Code on macOS):
1. Log into your Apple Developer account.
2. Navigate to Certificates, Identifiers & Profiles to create an App ID and Provisioning Profile.
3. Download the *.mobileprovision file and copy it to the ~/Library/MobileDevice/Provisioning Profiles folder.

Step 1: Set Up the .NET MAUI Document Scanner Project

Dynamsoft provides a .NET MAUI sample project demonstrating how to automatically capture and normalize documents from a camera stream. Based on this sample, we’ll make a few modifications:

Update the target framework from net7.0 to net8.0.
Add a button to trigger document capture and rectification.
Allow users to share the normalized document to other apps.

Update the Target Framework from .NET 7 to .NET 8

The latest .NET version is 8.0, while the sample project uses .NET 7.0. To update the target framework:

Open the .csproj file and change the TargetFramework value from net7.0 to net8.0.

Add <SupportedOSPlatformVersion> to the PropertyGroup element to ensure compatibility:

 <PropertyGroup Condition="$(TargetFramework.Contains('-ios'))">
     <SupportedOSPlatformVersion>11.0</SupportedOSPlatformVersion>
 </PropertyGroup>

Add a Capture Button to Trigger Document Scanning

Update the CameraPage.xaml file to add a round button for document capture:

 <?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"
              xmlns:controls="clr-namespace:Dynamsoft.CameraEnhancer.Maui;assembly=Dynamsoft.CameraEnhancer.Maui"
              x:Class="AutoNormalize.CameraPage"
              Title="Auto Normalize">
     <AbsoluteLayout>
         <controls:CameraView x:Name="camera"
                              AbsoluteLayout.LayoutBounds="0,0,1,1"
                              AbsoluteLayout.LayoutFlags="All"/>
         <!-- Capture Button -->
         <Button x:Name="captureButton"
                 BackgroundColor="White"
                 WidthRequest="70"
                 HeightRequest="70"
                 CornerRadius="35"
                 Clicked="OnCaptureButtonClicked"
                 HorizontalOptions="Center"
                 VerticalOptions="End"
                 AbsoluteLayout.LayoutBounds="0.5, 0.9, 90, 90"
                 AbsoluteLayout.LayoutFlags="PositionProportional"/>
    
     </AbsoluteLayout>
 </ContentPage>
    

Implement the OnCaptureButtonClicked event handler in the CameraPage.xaml.cs file:

 bool isReady = false;

 private void OnCaptureButtonClicked(object sender, EventArgs e)
 {
     isReady = true;
 }

 public void OnNormalizedImagesReceived(NormalizedImagesResult result)
 {
     if (result?.Items?.Count > 0 && isReady)
     {
         router?.StopCapturing();
         enhancer?.ClearBuffer();
         var data = result.Items[0].ImageData;

         MainThread.BeginInvokeOnMainThread(async () =>
         {
             await Navigation.PushAsync(new ImagePage(data));
         });
     }
 }

Reset the isReady flag in the OnAppearing event handler:

 protected override async void OnAppearing()
 {
     base.OnAppearing();
     isReady = false;
     ...
 }

In the ImagePage.xaml file, add a ToolbarItem as a share button:

 <?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="AutoNormalize.ImagePage"
              Title="ImagePage">
    
         <!-- Toolbar Item for Share Button -->
         <ContentPage.ToolbarItems>
                 <ToolbarItem Text="Share"
                              Order="Primary"
                              Priority="0"
                              Clicked="OnShareButtonClicked"/>
         </ContentPage.ToolbarItems>
    
         <Grid RowDefinitions="Auto, *, Auto"
               ColumnDefinitions="*,*,*">
                 <Button Text="gray"
                         Grid.Row="0"
                         Grid.Column="0"
                         Margin="10,20"
                         Clicked="OnButtonClicked"/>
                 <Button Text="color"
                         Grid.Row="0"
                         Grid.Column="1"
                         Margin="10,20"
                         Clicked="OnButtonClicked"/>
                 <Button Text="binary"
                         Grid.Row="0"
                         Grid.Column="2"
                         Margin="10,20"
                         Clicked="OnButtonClicked"/>
    
                 <Image x:Name="image"
                        Grid.Row="1"
                        Grid.ColumnSpan="3"
                        Margin="20,0,20,20"/>
    
         </Grid>
 </ContentPage>

Implement the OnShareButtonClicked event handler in the ImagePage.xaml.cs file:

 private void normalize(EnumImageColourMode type)
 {
     var name = EnumPresetTemplate.PT_NORMALIZE_DOCUMENT;
     var settings = cvr.GetSimplifiedSettings(name);
     settings.DocumentSettings.ColourMode = type;
     cvr.UpdateSettings(name, settings);
     var result = cvr.Capture(data, name);
     if (result?.Items?.Count > 0 && result.Items[0].Type == EnumCapturedResultItemType.CRIT_NORMALIZED_IMAGE)
     {
         _item = (NormalizedImageResultItem)result.Items[0];
         image.Source = _item.ImageData.ToImageSource();
     }
 }

 private async void OnShareButtonClicked(object sender, EventArgs e)
 {
     if (_item == null)
     {
         await DisplayAlert("Error", "Image is not shareable.", "OK");
         return;
     }

     var imageSource = _item.ImageData.ToImageSource();
     if (imageSource is StreamImageSource streamImageSource)
     {
         var stream = await streamImageSource.Stream(CancellationToken.None);

         var tempFile = Path.Combine(FileSystem.CacheDirectory, "shared_image.jpg");
         using (var memoryStream = new MemoryStream())
         {
             await stream.CopyToAsync(memoryStream);
             await File.WriteAllBytesAsync(tempFile, memoryStream.ToArray());
         }

         await Share.RequestAsync(new ShareFileRequest
         {
             Title = "Share Image",
             File = new ShareFile(tempFile)
         });
     }
     else
     {
         await DisplayAlert("Error", "Image is not shareable.", "OK");
     }
 }

Explanation

The _item variable stores the normalized image data. After assigning the image data to the Image control, image.Source is not directly available for image operations.
To share the image, save it as a temporary file and use the Share.RequestAsync method to share the file.

Step 2: Run and Test the .NET MAUI Document Scanner

In Visual Studio Code, press F1 to open the command palette and pick a target device to run the app.
Capture and normalize a document, then share it with other apps.

Common Issues and Edge Cases

iOS provisioning profile errors: If the app fails to deploy on a physical iOS device, verify that your App ID and provisioning profile match the bundle identifier in your .csproj. An expired or mismatched profile is the most common cause of signing failures.
Camera permission not granted: On both Android and iOS, the app requires camera access. If the CameraView shows a blank screen, check that camera permissions are declared in AndroidManifest.xml (Android) and Info.plist (iOS), and that the user has granted the permission at runtime.
NormalizedImagesResult returns empty items: This can occur if the document edges are not clearly visible against the background. Ensure adequate lighting and contrast between the document and the surface it rests on.

Source Code

https://github.com/yushulx/maui-barcode-mrz-document-scanner/tree/main/examples/DocumentScanner