Azure Blob Storage + .NET - File Upload, Download, List, and Delete Example

To work with Azure Blob Storage in a .NET application for uploading, listing, downloading, and deleting files, follow these steps:

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1. Install Required NuGet Package

Add the Azure.Storage.Blobs package to your project:

dotnet add package Azure.Storage.Blobs

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2. Set Up Azure Blob Storage Client

Use the BlobServiceClient, BlobContainerClient, and BlobClient classes for interacting with Blob Storage.

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3. Code Examples

Initialize the Blob Service Client

using Azure.Storage.Blobs;

// Connection string from Azure portal
string connectionString = "YourAzureBlobStorageConnectionString";
string containerName = "your-container-name";

// Create a BlobServiceClient
BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);

// Get a reference to the container
BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient(containerName);

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Upload a File

public async Task UploadFileAsync(string filePath)
{
    string blobName = Path.GetFileName(filePath);
    BlobClient blobClient = containerClient.GetBlobClient(blobName);

    using FileStream fileStream = File.OpenRead(filePath);
    await blobClient.UploadAsync(fileStream, overwrite: true);
    Console.WriteLine($"File {blobName} uploaded successfully.");
}

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List Files

public async Task ListFilesAsync()
{
    await foreach (var blobItem in containerClient.GetBlobsAsync())
    {
        Console.WriteLine($"Blob Name: {blobItem.Name}");
    }
}

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Download a File

public async Task DownloadFileAsync(string blobName, string downloadFilePath)
{
    BlobClient blobClient = containerClient.GetBlobClient(blobName);

    using FileStream downloadFileStream = File.OpenWrite(downloadFilePath);
    await blobClient.DownloadToAsync(downloadFileStream);
    Console.WriteLine($"File {blobName} downloaded successfully.");
}

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Delete a File

public async Task DeleteFileAsync(string blobName)
{
    BlobClient blobClient = containerClient.GetBlobClient(blobName);
    await blobClient.DeleteIfExistsAsync();
    Console.WriteLine($"File {blobName} deleted successfully.");
}

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4. Putting It All Together

public class AzureBlobStorageService
{
    private readonly BlobContainerClient _containerClient;

    public AzureBlobStorageService(string connectionString, string containerName)
    {
        BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
        _containerClient = blobServiceClient.GetBlobContainerClient(containerName);
    }

    public async Task UploadFileAsync(string filePath)
    {
        string blobName = Path.GetFileName(filePath);
        BlobClient blobClient = _containerClient.GetBlobClient(blobName);

        using FileStream fileStream = File.OpenRead(filePath);
        await blobClient.UploadAsync(fileStream, overwrite: true);
        Console.WriteLine($"File {blobName} uploaded successfully.");
    }

    public async Task ListFilesAsync()
    {
        await foreach (var blobItem in _containerClient.GetBlobsAsync())
        {
            Console.WriteLine($"Blob Name: {blobItem.Name}");
        }
    }

    public async Task DownloadFileAsync(string blobName, string downloadFilePath)
    {
        BlobClient blobClient = _containerClient.GetBlobClient(blobName);

        using FileStream downloadFileStream = File.OpenWrite(downloadFilePath);
        await blobClient.DownloadToAsync(downloadFileStream);
        Console.WriteLine($"File {blobName} downloaded successfully.");
    }

    public async Task DeleteFileAsync(string blobName)
    {
        BlobClient blobClient = _containerClient.GetBlobClient(blobName);
        await blobClient.DeleteIfExistsAsync();
        Console.WriteLine($"File {blobName} deleted successfully.");
    }
}

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5. Run the Service

static async Task Main(string[] args)
{
    string connectionString = "YourAzureBlobStorageConnectionString";
    string containerName = "your-container-name";
    AzureBlobStorageService blobService = new AzureBlobStorageService(connectionString, containerName);

    // Upload
    await blobService.UploadFileAsync("path/to/your/file.txt");

    // List
    await blobService.ListFilesAsync();

    // Download
    await blobService.DownloadFileAsync("file.txt", "path/to/save/file.txt");

    // Delete
    await blobService.DeleteFileAsync("file.txt");
}

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6. Additional Notes

• Ensure your connection string has proper permissions for the operations.
• Handle exceptions with try-catch blocks to improve robustness.
• For production, consider using Azure Managed Identity or Key Vault for secure credential management.