I migrated from the legacy driver to the new implementation of GridFs and when I run a FindAsync() that returns files that were previously stored with legacy version an invalid cast exception is thrown when trying to access the ObjectId via FileInfo.Id property.

I am wondering if this is a result of earlier code we had that set the Id during upload? My assumption is that these Id's are not compatible with ObjectId. [GridFs.Upload(file, id, new MongoGridFSCreateOptions()

{ Id = id }

);]

Details of Exception

fileInfo.Id
'fileInfo.Id' threw an exception of type 'System.InvalidCastException'
Data:

{System.Collections.ListDictionaryInternal}

HResult: -2147467262
HelpLink: null
InnerException: null
Message: "Unable to cast object of type 'MongoDB.Bson.BsonString' to type 'MongoDB.Bson.BsonObjectId'."
Source: "MongoDB.Driver.GridFS"
StackTrace: " at MongoDB.Driver.GridFS.GridFSFileInfo.get_Id()"
TargetSite:

{MongoDB.Bson.ObjectId get_Id()}

fileInfo.IdAsBsonValue

{55b66883acaf044ce05919ff}
AsBoolean: 'fileInfo.IdAsBsonValue.AsBoolean' threw an exception of type 'System.InvalidCastException'
AsBsonArray: 'fileInfo.IdAsBsonValue.AsBsonArray' threw an exception of type 'System.InvalidCastException'
AsBsonBinaryData: 'fileInfo.IdAsBsonValue.AsBsonBinaryData' threw an exception of type 'System.InvalidCastException'
AsBsonDateTime: 'fileInfo.IdAsBsonValue.AsBsonDateTime' threw an exception of type 'System.InvalidCastException'
AsBsonDocument: 'fileInfo.IdAsBsonValue.AsBsonDocument' threw an exception of type 'System.InvalidCastException'
AsBsonJavaScript: 'fileInfo.IdAsBsonValue.AsBsonJavaScript' threw an exception of type 'System.InvalidCastException'
AsBsonJavaScriptWithScope: 'fileInfo.IdAsBsonValue.AsBsonJavaScriptWithScope' threw an exception of type 'System.InvalidCastException'
AsBsonMaxKey: 'fileInfo.IdAsBsonValue.AsBsonMaxKey' threw an exception of type 'System.InvalidCastException'
AsBsonMinKey: 'fileInfo.IdAsBsonValue.AsBsonMinKey' threw an exception of type 'System.InvalidCastException'
AsBsonNull: 'fileInfo.IdAsBsonValue.AsBsonNull' threw an exception of type 'System.InvalidCastException'
AsBsonRegularExpression: 'fileInfo.IdAsBsonValue.AsBsonRegularExpression' threw an exception of type 'System.InvalidCastException'
AsBsonSymbol: 'fileInfo.IdAsBsonValue.AsBsonSymbol' threw an exception of type 'System.InvalidCastException'
AsBsonTimestamp: 'fileInfo.IdAsBsonValue.AsBsonTimestamp' threw an exception of type 'System.InvalidCastException'
AsBsonUndefined: 'fileInfo.IdAsBsonValue.AsBsonUndefined' threw an exception of type 'System.InvalidCastException'
AsBsonValue: {55b66883acaf044ce05919ff}

AsByteArray: 'fileInfo.IdAsBsonValue.AsByteArray' threw an exception of type 'System.InvalidCastException'
AsDateTime: 'fileInfo.IdAsBsonValue.AsDateTime' threw an exception of type 'System.InvalidCastException'
AsDouble: 'fileInfo.IdAsBsonValue.AsDouble' threw an exception of type 'System.InvalidCastException'
AsGuid: 'fileInfo.IdAsBsonValue.AsGuid' threw an exception of type 'System.InvalidCastException'
AsInt32: 'fileInfo.IdAsBsonValue.AsInt32' threw an exception of type 'System.InvalidCastException'
AsInt64: 'fileInfo.IdAsBsonValue.AsInt64' threw an exception of type 'System.InvalidCastException'
AsLocalTime: 'fileInfo.IdAsBsonValue.AsLocalTime' threw an exception of type 'System.InvalidCastException'
AsNullableBoolean: 'fileInfo.IdAsBsonValue.AsNullableBoolean' threw an exception of type 'System.InvalidCastException'
AsNullableDateTime: 'fileInfo.IdAsBsonValue.AsNullableDateTime' threw an exception of type 'System.InvalidCastException'
AsNullableDouble: 'fileInfo.IdAsBsonValue.AsNullableDouble' threw an exception of type 'System.InvalidCastException'
AsNullableGuid: 'fileInfo.IdAsBsonValue.AsNullableGuid' threw an exception of type 'System.InvalidCastException'
AsNullableInt32: 'fileInfo.IdAsBsonValue.AsNullableInt32' threw an exception of type 'System.InvalidCastException'
AsNullableInt64: 'fileInfo.IdAsBsonValue.AsNullableInt64' threw an exception of type 'System.InvalidCastException'
AsNullableObjectId: 'fileInfo.IdAsBsonValue.AsNullableObjectId' threw an exception of type 'System.InvalidCastException'
AsObjectId: 'fileInfo.IdAsBsonValue.AsObjectId' threw an exception of type 'System.InvalidCastException'
AsRegex: 'fileInfo.IdAsBsonValue.AsRegex' threw an exception of type 'System.InvalidCastException'
AsString: "55b66883acaf044ce05919ff"
AsUniversalTime: 'fileInfo.IdAsBsonValue.AsUniversalTime' threw an exception of type 'System.InvalidCastException'
BsonType: String
IsBoolean: false
IsBsonArray: false
IsBsonBinaryData: false
IsBsonDateTime: false
IsBsonDocument: false
IsBsonJavaScript: false
IsBsonJavaScriptWithScope: false
IsBsonMaxKey: false
IsBsonMinKey: false
IsBsonNull: false
IsBsonRegularExpression: false
IsBsonSymbol: false
IsBsonTimestamp: false
IsBsonUndefined: false
IsDateTime: false
IsDouble: false
IsGuid: false
IsInt32: false
IsInt64: false
IsNumeric: false
IsObjectId: false
IsString: true
IsValidDateTime: false
RawValue: "55b66883acaf044ce05919ff"
Value: "55b66883acaf044ce05919ff"