Add description to Office365 Planner task throug Grap API

Question

I'm trying to add a description to an Office365 Planner task via Grap API.

The necessary HttpRequest requires a "If-Match" entry in its headers with an Etag value. I get the Etag from a former request to the task details. The Etag I get looks like this:

"@odata.etag": "W/\"JzEtVGFza0RldGFpbHMgQEBAQEBAQEBAQEBAQEBASCc=\""

As you can see, there are two \\" within this Etag string which cause some troubles.

In my code I've tried the following three ways to create a "If-Match" header without succes:

1. request.Headers.IfMatch.Add(new EntityTagHeaderValue(etag));
2. request.Headers.IfMatch.Add(EntityTagHeaderValue.Parse(etag));
3. request.Headers.TryAddWithoutValidation("If-Match", etag);

Line 1. causes an exception, because of the " within the string. Line 2. and 3. lead to a "not found" response of the request, because the \\ character is missing in the Etag. The VS debugger shows the following content of the IfMatch property:

"W/"JzEtVGFza0RldGFpbHMgQEBAQEBAQEBAQEBAQEBASCc=""

Thanks for help.

Answer 1

Ok, problem solved.

The Etag was not the reason for the non working update request. The received error was misleading.

Needed to use HttpMethod "PATCH" instead of "POST".