Unable to post inline images along with the message in Microsoft Teams via Microsoft Graph API using C#

问题

I have been trying to post the images along with the message in Microsoft Teams via MS Graph API using C# but unable to do so.

Below is the code I have tried:

string userName = ConfigurationManager.AppSettings["UserName"];
string password = ConfigurationManager.AppSettings["Password"];

System.Security.SecureString passWordSecureString = new System.Security.SecureString();

foreach (char c in password.ToCharArray()) passWordSecureString.AppendChar(c);

var clientId = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
var tenantId = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";

string[] scopes = { "ChannelMessage.Send", "Group.ReadWrite.All", "User.Read" };

IPublicClientApplication publicClientApplication = PublicClientApplicationBuilder
  .Create(clientId)
  .WithTenantId(tenantId)
  .Build();

//creating the graph user context.
UsernamePasswordProvider authProvider = new UsernamePasswordProvider(publicClientApplication, scopes);            

var chatMessage = new ChatMessage
{
    Subject = null,
    Body = new ItemBody
    {
        ContentType = BodyType.Html,
        Content = "Hello world </br><div><div>\n<div><span><img height=\"297\" src=\"../hostedContents/1/$value\" width=\"297\" style=\"vertical-align:bottom; width:297px; height:297px\"></span>\n\n</div>\n\n\n</div>\n</div>"
    },  
};

 ChatMessageHostedContent chatMessageHostedContent = new ChatMessageHostedContent
 {
        ContentBytes = Encoding.ASCII.GetBytes("iVBORw0KGgoAAAANSUhEUgAAASkA..."),
        ContentType = "image/png",
        AdditionalData = new Dictionary<string, object>()
        {
             {"@microsoft.graph.temporaryId", "1"}
        }
 };

 IChatMessageHostedContentsCollectionPage chatMessageHostedContentsCollectionPage = new ChatMessageHostedContentsCollectionPage();

 chatMessageHostedContentsCollectionPage.Add(chatMessageHostedContent);

 if (chatMessageHostedContentsCollectionPage.Count > 0)
   chatMessage.HostedContents = chatMessageHostedContentsCollectionPage;

 ChatMessage sentMessage = await graphClient.Teams["{id}"].Channels["{id}"].Messages
    .Request()
    .AddAsync(chatMessage);

The image is getting uploaded but it's not showing anything i.e. it's broken/corrupted as shown below:

I have even tried the below code to add an image to the sent message but its throwing an "unknown error" exception.

await graphClient.Teams["{id}"].Channels["{id}"].Messages[sentMessage.Id].HostedContents
        .Request()
        .AddAsync(chatMessageHostedContent);

I am able to post the same image along with text successfully using the Post HTTP method in MS Graph Explorer with below URL & payload.

https://graph.microsoft.com/beta/teams/{id}/channels/{id}/messages

{"body":{"contentType":"html","content":"Hello world </br><div><div>\n<div><span><img height=\"297\" src=\"../hostedContents/1/$value\" width=\"297\" style=\"vertical-align:bottom;  max-width: 100%; height:auto\"></span>\n\n</div>\n\n\n</div>\n</div>"},"hostedContents":[{"@microsoft.graph.temporaryId":"1","contentBytes":"iVBORw0KGgoAAAANSUhEUgAAASkAAAEpCA...","contentType":"image/png"}]}

Can anybody suggest what is wrong in the code?

来源：https://stackoverflow.com/questions/64028614/unable-to-post-inline-images-along-with-the-message-in-microsoft-teams-via-micro