Getting Started with Microsoft Graph API in C#
- Make sure you have the Microsoft Graph SDK for .NET installed. You can do this by adding the Microsoft.Graph NuGet package to your project.
- Create an instance of the GraphServiceClient. This client is the main entry point to the Microsoft Graph API, and you'll need to authenticate it with a valid access token.
var graphClient = new GraphServiceClient(authProvider);
Authentication
- Implement an authentication provider. The GraphServiceClient requires an IAuthenticationProvider to function, which handles obtaining and providing the access token.
- You can utilize a library like Microsoft.Identity.Client (MSAL) to simplify the authentication process.
public class AuthProvider : IAuthenticationProvider
{
private IPublicClientApplication _clientApp;
public AuthProvider()
{
_clientApp = PublicClientApplicationBuilder.Create(clientId)
.WithAuthority(authorityUri)
.WithDefaultRedirectUri()
.Build();
}
public async Task AuthenticateRequestAsync(HttpRequestMessage request)
{
var result = await _clientApp.AcquireTokenSilent(scopes, accounts.FirstOrDefault())
.ExecuteAsync();
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", result.AccessToken);
}
}
Accessing SharePoint Data
- To access SharePoint data, you'll refer to the GraphServiceClient to interact with SharePoint resources.
- Use the Sites API to access a SharePoint site, and you can then navigate to lists, documents, or other resources.
var site = await graphClient.Sites["{site-id}"].Request().GetAsync();
Reading SharePoint List Items
- Once you have a reference to the site, you can interact with lists, such as reading items from a list.
var listItems = await graphClient.Sites["{site-id}"].Lists["{list-id}"].Items.Request().GetAsync();
foreach (var item in listItems)
{
Console.WriteLine(item.Fields.AdditionalData["Title"]);
}
Uploading Files to a Document Library
- To upload a file, interact with the document libraries under the SharePoint site.
using (var stream = new FileStream("path/to/your/file.txt", FileMode.Open))
{
await graphClient.Sites["{site-id}"]
.Drives["{drive-id}"]
.Root
.ItemWithPath("DemoFolder/file.txt")
.Content
.Request()
.PutAsync<DriveItem>(stream);
}
Handling Errors
- Implement try-catch blocks to handle exceptions that may occur during API calls, which helps in capturing and responding to errors gracefully.
try
{
// Your code to call the Graph API
}
catch (ServiceException ex)
{
Console.WriteLine($"Error: {ex.Message}");
}
Testing & Debugging
- Confirm the correct scopes and permissions in your app registration or consent process to ensure you have sufficient access to perform your desired operations on SharePoint data.
- Make use of logging and debugging tools to ensure the requests to Microsoft Graph API are structured and authenticated correctly.
