CODEWITHSUNDEEP
c#.netmongodbnosql
Codesharper
Codesharper

Reputation: 41

Removing an element from an array in MongoDB

I am new to learning how to use MongoDB and am stuck pretty early on, so hoping someone can help me out with a simple example.

I can successfully connect to a Mongo server and create a collection and create objects to put in it. I am doing all of this through c# and the c# driver.

I have the following custom objects defined in my code.

public class Feature
{
    public string FeatureName { get; set; }
    public ObjectId Id { get; set; }
    public List<Scenario> Scenarios { get; set; } 
}

public class Scenario
{
    private string _notes;
    public string ScenarioName { get; set; }
    public List<string> Givens { get; set; }
    public List<string> Whens { get; set; }
    public List<string> Thens { get; set; }
    public string Explanation { get; set; }
    public string Notes { get; set; }
}

As you can see, the Feature object contains a property which is a list of scenarios.

In my Mongo collection I have a Feature object that contains 3 scenarios. What I want to do in C# is write a method that can remove a specific scenario from a feature:

  1. User provides a feature and scenario name to a method
  2. Method checks the feature, looking through the list within it, for a scenario where the scenario.scenarioname matches the scenario name passed in to the method
  3. If it exists, then remove the scenario from the feature and update Mongo and return a bool of true. If it doesn't exist return false

I am sure that this is probably going to be obvious when I see an example, but I have tried and get stuck trying to work through the List property looking for a property on a sub object.

I hope that all makes sense??!?

Thanks in advance.

P

Upvotes: 2

Views: 1308

Answers (1)

Codesharper
Codesharper

Reputation: 41

Resolved it myself...

public bool DeleteScenario(string featureName, string scenarioName)
    {
        var collection = GetCollection<Feature>();
        var query = Query.EQ("FeatureName", featureName);
        var resultingFeature = collection.Find(query).SetLimit(1).FirstOrDefault();

        if (resultingFeature == null)
        {
            return false;
        }

        // we have found our feature and it exists.

        foreach (var scenario in resultingFeature.Scenarios)
        {
            if (scenario.ScenarioName == scenarioName)
            {
                resultingFeature.Scenarios.Remove(scenario);
                collection.Save(resultingFeature);
                return true;
            }
        }

        return true;

    }

Upvotes: 2

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