I have no idea what could be causing the error about graph API Call

Question

I am trying to add and change extended properties of devices registered in AzureAD using C#. But I am getting the following error, I don't know why...

Below is the part about the Graph API call. I used the document provided by MS Docs as it is, and it works normally in Graph API Explorer.

[C# Code]

var device = await graphclient.Devices
    .Request()
    .Filter(ftr)
    .Select("Id")
    .GetAsync();

string objectId = device.CurrentPage.First().Id.ToString().Trim();

var extattr = new Device
{
    AdditionalData = new Dictionary<string, object>(){
        {"extensionAttributes", "{\"extensionAttribute1\":\"BYOD-Device2\"}"}
    }
};

await graphclient.Devices[objectId]
     .Request()
     .UpdateAsync(extattr);

[ErrorCode]

Status Code: BadRequest
Microsoft.Graph.ServiceException: Code: Request_BadRequest
Message: A 'PrimitiveValue' node with non-null value was found when trying to read the value of the property 'extensionAttributes'; however, a 'StartArray' node, a 'StartObject' node, or a 'PrimitiveValue' node with null value was expected.

The current situation is that extensionAttribute1 has the value 'BYOD-Device'.

Is there anyone out there who can help me solve this error?

Answer 1

The value of the extensionAttribute1 property is not a JSON string, but a JSON object. Try

AdditionalData = new Dictionary<string, object>(){
    {"extensionAttributes", new Dictionary<string, object>(){
        {"extensionAttribute1", "BYOD-Device2"}
    }}
}