Cannot deserialize string from BsonType ObjectId in MongoDb C#

Question

I am getting error "Cannot deserialize string from BsonType ObjectId" while trying to get all the record from MongoDb in C# WebAPI

My Id is

[BsonId]
public string Id { get; set; }

After Changing it to

[BsonRepresentation(BsonType.ObjectId)] 
public string Id { get; set; }

its working fine

But while i'm calling post method, its giving me different error

"'d05e139c-3a48-4213-bd89-eba0c22c3c6f' is not a valid 24 digit hex string."

How can solve this problem

My Model is:

public class EstablishmentDetails
{

    [BsonRepresentation(BsonType.ObjectId)] 
    public string Id { get; set; }
    public string EstablishmentName { get; set; }
    public string EstablishmentType { get; set; }
    public string Address { get; set; }
    public string City { get; set; }
    public int StateID { get; set; }
    public Int32 PIN { get; set; }
    public Int64 PhoneNumber { get; set; }
    public string EmailID { get; set; }
    public bool Published { get; set; }
    public string CreatedDate { get; set; }
    public string ModifiedDate { get; set; }
}

My repository fro Get method

public IEnumerable<EstablishmentDetails> GetAllEstablishmentDetails()
    {
        if (Convert.ToInt32(mCollection.Count()) > 0)
        {
            var EstablishmentDetailsCollection = mCollection.FindAllAs(typeof(EstablishmentDetails));

            if (EstablishmentDetailsCollection.Count() > 0)
            {
                foreach (EstablishmentDetails item in EstablishmentDetailsCollection)
                {
                    establishmentDetails.Add(item);
                }
            }
        }
        var results = establishmentDetails.AsQueryable();
        return results;
    }

My repository for Post method

public EstablishmentDetails Add(EstablishmentDetails ed)
    {
        if (string.IsNullOrEmpty(ed.Id))
        {
            ed.Id = Guid.NewGuid().ToString();
        }

        mCollection.Save(ed);
        return ed;
    }

Answer 1

Instead of using

ed.Id = Guid.NewGuid().ToString();

I used

ed.Id = MongoDB.Bson.ObjectId.GenerateNewId().ToString();

For generating Id

Its working fine : )