# Getting Started with Dynamsoft Barcode Reader SDK .NET Edition
In this guide, you will learn step by step on how to build a barcode reading application with Dynamsoft Barcode Reader SDK using C#.
> Read more on [Dynamsoft Barcode Reader Features](https://www.dynamsoft.com/barcode-reader/features)
- [Getting Started with Dynamsoft Barcode Reader SDK .NET Edition](#getting-started-with-dynamsoft-barcode-reader-sdk-net-edition)
- [System Requirements](#system-requirements)
- [Build Your First Application](#build-your-first-application)
- [Create a New Project](#create-a-new-project)
- [Install the NuGet Package](#install-the-nuget-package)
- [Import the Namespace](#import-the-namespace)
- [Initialize the License Key](#initialize-the-license-key)
- [Create a CaptureVisionRouter Instance](#create-a-capturevisionrouter-instance)
- [Invoke the Barcode Capturing](#invoke-the-barcode-capturing)
- [Filter and Get Barcode Details](#filter-and-get-barcode-details)
- [Build and Run the Project](#build-and-run-the-project)
- [Process Multiple Images](#process-multiple-images)
- [Import the Additional Namespace.](#import-the-additional-namespace)
- [Create an ImageSource as the Input](#create-an-imagesource-as-the-input)
- [Implement a CapturedResultReceiver as the Output Listener](#implement-a-capturedresultreceiver-as-the-output-listener)
- [Handle Capture Stoppage by Implementing a ImageSource State Listener](#handle-capture-stoppage-by-implementing-a-imagesource-state-listener)
- [Register the Input, Output Listener and ImageSource State Listener to the CaptureVisionRouter Instance](#register-the-input-output-listener-and-imagesource-state-listener-to-the-capturevisionrouter-instance)
- [Start the Capturing Process](#start-the-capturing-process)
- [Build and Run the Project Again](#build-and-run-the-project-again)
## System Requirements
To find out whether your environment is supported, please read the [System Requirements](https://www.dynamsoft.com/barcode-reader/docs/server/programming/dotnet/index.md#system-requirements).
## Build Your First Application
Let's start by creating a console application which demonstrates how to use the minimum code to read barcodes from an image file.
> You can download the entire source code from here.
### Create a New Project
Start Visual Studio or your preferred C# IDE.
Create a new C# Console Application project. Let's name it `DBRCSharpSample`.
### Install the NuGet Package
In the Solution Explorer, right-click on your project and select Manage NuGet Packages.
Search for and install the `Dynamsoft.DotNet.BarcodeReader.Bundle` nuget package.
> If you prefer to use the offline packages, please
>
> Download the `.NET Package` now and extract it into a directory of your choice.
>
> You can find the nuget package under `.\DynamsoftBarcodeReader\Packages`.
### Import the Namespace
Open the `Program.cs` file and add the following namespaces.
```csharp
using Dynamsoft.DBR;
using Dynamsoft.Core;
using Dynamsoft.CVR;
using Dynamsoft.License;
```
### Initialize the License Key
Open the `Program.cs` file and add the following code inside the `Main` method to initialize the license for using the SDK in the application:
```csharp
int errorCode = 1;
string errorMsg;
errorCode = LicenseManager.InitLicense("DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9", out errorMsg);
if (errorCode != (int)EnumErrorCode.EC_OK && errorCode != (int)EnumErrorCode.EC_LICENSE_CACHE_USED)
Console.WriteLine("License initialization error: " + errorMsg);
```
> The string "DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9" here is a free public trial license. Note that network connection is required for this license to work. Alternatively, you can request a 30-day **offline** free trial license from the Customer Portal.
### Create a CaptureVisionRouter Instance
```csharp
using (CaptureVisionRouter cvRouter = new CaptureVisionRouter())
{
//code for invoking the barcode capturing
}
```
> [!IMPORTANT]
> Instances of `CaptureVisionRouter` are not thread-safe.
> Do not access the same `CaptureVisionRouter` instance from multiple threads concurrently.
> Create a separate instance for each thread if concurrent processing is required.
### Invoke the Barcode Capturing
```csharp
using (CaptureVisionRouter cvRouter = new CaptureVisionRouter())
{
string imageFile = "[PATH-TO-THE-IMAGE-FILE]";
CapturedResult? result = cvRouter.Capture(imageFile, PresetTemplate.PT_READ_BARCODES);
//code for filtering and getting barcode details
}
```
> Please change the `[PATH-TO-THE-IMAGE-FILE]` to a real barcode image file path.
### Filter and Get Barcode Details
```csharp
if (result == null)
{
Console.WriteLine("No barcode detected.");
}
else if(result.GetErrorCode() != 0)
{
Console.WriteLine("Error: " + result.GetErrorCode() + ", " + result.GetErrorString());
}
else
{
DecodedBarcodesResult barcodesResult = result.GetDecodedBarcodesResult();
if (barcodesResult != null)
{
BarcodeResultItem[] items = barcodesResult.GetItems();
Console.WriteLine("Decoded " + items.Length + " barcodes");
foreach (BarcodeResultItem barcodeItem in items)
{
Console.WriteLine("Result " + (Array.IndexOf(items, barcodeItem) + 1));
Console.WriteLine("Barcode Format: " + barcodeItem.GetFormatString());
Console.WriteLine("Barcode Text: " + barcodeItem.GetText());
}
}
}
```
### Build and Run the Project
Save the `Program.cs` file and then compile and run the program using your IDE (such as Visual Studio). You will see the output message in the console like
```
Decoded 2 barcodes
Result 1
Barcode Format: XXX
Barcode Text: XXX
Result 2
Barcode Format: XXX
Barcode Text: XXX
```
## Process Multiple Images
If, instead of processing one single image, you need to process many images at once, you can follow these steps:
> These steps follow the step [Create a CaptureVisionRouter Instance](#create-a-capturevisionrouter-instance) mentioned above.
> You can download the entire source code from here.
### Import the Additional Namespace.
```csharp
using Dynamsoft.Utility;
```
### Create an ImageSource as the Input
An `ImageSource` is required when creating a multi-image processing application. You can either utilize ready-made image sources such as [`FileFetcher`](https://www.dynamsoft.com/capture-vision/docs/server/programming/dotnet/api-reference/utility/file-fetcher.md) and [`DirectoryFetcher`](https://www.dynamsoft.com/capture-vision/docs/server/programming/dotnet/api-reference/utility/directory-fetcher.md), or customize your own image source based on the base class [`ImageSourceAdapter`](https://www.dynamsoft.com/capture-vision/docs/server/programming/dotnet/api-reference/core/basic-classes/image-source-adapter.md).
In this sample, we will use the `DirectoryFetcher` to retrieve images from a local directory.
```csharp
DirectoryFetcher fetcher = new DirectoryFetcher();
fetcher.SetDirectory("[THE DIRECTORY THAT HOLDS THE IMAGES]");
```
> Please change the `[THE DIRECTORY THAT HOLDS THE IMAGES]` to full path of the directory holding barcode image files.
### Implement a CapturedResultReceiver as the Output Listener
Create a class `MyCapturedResultReceiver` to implement the `CapturedResultReceiver` interface, and get the barocde results in `OnDecodedBarcodesReceived` callback function.
```csharp
class MyCapturedResultReceiver : CapturedResultReceiver
{
public override void OnDecodedBarcodesReceived(DecodedBarcodesResult result)
{
FileImageTag? tag = (FileImageTag?)result.GetOriginalImageTag();
Console.WriteLine("File: " + tag.GetFilePath());
if (result.GetErrorCode() != (int)EnumErrorCode.EC_OK)
{
Console.WriteLine("Error: " + result.GetErrorString());
}
else
{
BarcodeResultItem[] items = result.GetItems();
Console.WriteLine("Decoded " + items.Length + " barcodes");
foreach (BarcodeResultItem item in items)
{
Console.WriteLine("Result " + (Array.IndexOf(items, item) + 1));
Console.WriteLine("Barcode Format: " + item.GetFormatString());
Console.WriteLine("Barcode Text: " + item.GetText());
}
}
Console.WriteLine();
}
}
```
### Handle Capture Stoppage by Implementing a ImageSource State Listener
Create a class `MyImageSourceStateListener` to implement the `IImageSourceStateListener` interface, and call StopCapturing in `OnImageSourceStateReceived` callback function when the state is `ISS_EXHAUSTED`.
```csharp
class MyImageSourceStateListener : IImageSourceStateListener
{
private CaptureVisionRouter? cvRouter = null;
public MyImageSourceStateListener(CaptureVisionRouter cvRouter)
{
this.cvRouter = cvRouter;
}
public void OnImageSourceStateReceived(EnumImageSourceState state)
{
if (state == EnumImageSourceState.ISS_EXHAUSTED)
{
if (cvRouter != null)
{
cvRouter.StopCapturing();
}
}
}
}
```
### Register the Input, Output Listener and ImageSource State Listener to the CaptureVisionRouter Instance
```csharp
cvRouter.SetInput(fetcher);
CapturedResultReceiver receiver = new MyCapturedResultReceiver();
cvRouter.AddResultReceiver(receiver);
MyImageSourceStateListener listener = new MyImageSourceStateListener(cvRouter);
cvRouter.AddImageSourceStateListener(listener);
```
### Start the Capturing Process
Call the method `StartCapturing()` to start processing all the images in the specified folder.
```csharp
errorCode = cvRouter.StartCapturing(PresetTemplate.PT_READ_BARCODES, true, out errorMsg);
if (errorCode != (int)EnumErrorCode.EC_OK)
{
Console.WriteLine("error: " + errorMsg);
}
```
During the process, the callback function `OnDecodedBarcodesReceived()` is triggered each time processing of an image is finished. After all images are processed, the listener function `OnImageSourceStateReceived()` will be triggered while the image source state is `ISS_EXHAUSTED` and the process is stopped with the method `StopCapturing()`.
### Build and Run the Project Again
Please refer to [Build and Run the Project](#build-and-run-the-project).