Why do I get the "reference not set to an instance of an object?

Question

I am working with the new CosmosDB SDK v3 https://learn.microsoft.com/en-us/azure/cosmos-db/sql-api-sdk-dotnet-standard and a very simple insert, I have verified all the objects are indeed not null and have reasonable values but I still get the error message:

[1/12/2019 10:35:04] System.Private.CoreLib: Exception while executing function: HAPI_HM_Seasons. Microsoft.Azure.Cosmos.Direct: Object reference not set to an instance of an object.

I dont see why this is I must be missing something really basic here but I cant put my finger on it.

The code is as below:

List<SeasonInformation> seasonInformationList = new List<SeasonInformation>();

foreach(JObject document in listOfSeasons)
{
    SeasonInformation seasonInformation = new SeasonInformation
    {
        id = Guid.NewGuid().ToString(),
        Brand = brand,
        IntegrationSource = source,
        DocumentType = Enums.DocumentType.Season,
        UpdatedBy = "HAPI_HM_Seasons",
        UpdatedDate = DateTime.Now.ToString(),
        UpdatedDateUtc = string.Format("{0:yyyy-MM-ddTHH:mm:ss.FFFZ}", DateTime.UtcNow),
        OriginalData = document
    };
    seasonInformationList.Add(seasonInformation);
}

database = cosmosClient.GetDatabase(cosmosDBName);
container = database.GetContainer(cosmosDBCollectionNameRawData);

log.LogInformation(string.Format("HAPI_HM_Seasons BASIC setup done at {0:yyyy-MM-ddTHH:mm:ss.FFFZ}", DateTime.UtcNow));

log.LogInformation(string.Format("HAPI_HM_Seasons import {1} items BEGIN at {0:yyyy-MM-ddTHH:mm:ss.FFFZ}", DateTime.UtcNow, seasonInformationList.Count));

foreach(var season in seasonInformationList)
{

    ItemResponse<SeasonInformation> response = await container.CreateItemAsync(season);

}

I have verified that the List is populated and that the season variable in the loop contains the correct data so I am a bit stuck here.

The exception happens in the last foreach loop where I try CreateItemAsync into CosmosDB

All we can say from the information you've provided is that something is null... Perhaps list the objects you've checked are not null so we can check if you've missed any? — canton7, Dec 01 '19 at 10:51
What about the Task returned from `container.CreateItemAsync`? — canton7, Dec 01 '19 at 10:54
Assign it to a variable (instead of awaiting it) and check whether the variable contains null... — canton7, Dec 01 '19 at 10:58
So the question seems to be why that last `season` in the List produces this null ref error then. — Mark Schultheiss, Dec 01 '19 at 17:26
@MarkSchultheiss except it’s not null verified it many times — Matt Douhan, Dec 01 '19 at 17:28
Yes, but something in it does cause that error when it uses `HAPI_HM_Seasons` perhaps? Try to compare the next to last to the last list element for differences — Mark Schultheiss, Dec 01 '19 at 17:45

score 0 · Answer 1 · answered Dec 01 '19 at 10:56

0

As a best practice, you need to use Async method with await in all the Cosmosdb methods just to make sure that they are getting executed and you get the response,

and modify your CreateItemAsync as follows,

ItemResponse<SeasonInformation> response = await container.CreateItemAsync(season, new PartitionKey(season.whatever));

Here is the Sample Repository

answered Dec 01 '19 at 10:56

Sajeetharan

216,225
63
350
396

Got me one step closer System.Private.CoreLib: Exception while executing function: HAPI_HM_Seasons. Microsoft.Azure.Cosmos.Client: Response status code does not indicate success: 400 Substatus: 1001 Reason: (). – Matt Douhan Dec 01 '19 at 11:00
https://stackoverflow.com/questions/57678013/how-to-insert-json-into-cosmos-db-collection-using-c-sharp – Sajeetharan Dec 01 '19 at 11:01
I am passing the value like this await container.CreateItemAsync(season, new PartitionKey(season.Brand)); where /brand is the partitionKey and its value is HM so I am sending in HM – Matt Douhan Dec 01 '19 at 11:04
you need to set the value not the partitionkey itself – Sajeetharan Dec 01 '19 at 11:05
I am setting the value the value is HM, the partition Key itself is /brand, so in dataExplorer in azure portal it shows partition Key /brand and each document then shows hm in that column – Matt Douhan Dec 01 '19 at 11:08
try passing season.brand and what is the result? – Sajeetharan Dec 01 '19 at 12:05
same problem if I pass the season.brand or a fixed string – Matt Douhan Dec 01 '19 at 12:30
will open a case with msft and report back – Matt Douhan Dec 01 '19 at 12:54
@MattDouhan Did you ever get to the bottom of this? – Sean Jan 10 '20 at 12:36
@Sean I upgraded the SDK to latest preview and it started working – Matt Douhan Jan 10 '20 at 12:50

Why do I get the "reference not set to an instance of an object?

1 Answers1