C# MongoDb Driver Convert string to DateTime and for Filter Builder-CodePudding

 var builder = Builders<ModelClass>.Filter;
 var filter = builder.Where(x => x.Active);

if (fromDate.HasValue)
        {
            var date = fromDate.Value;
            var subfilter = builder.Where(x =>DateTime.Parse(x.EnrollmentDate) >= date);
            filter &= subfilter;
        }

Enrolment Date is Saved as a string public string EnrollmentDate{ get; set; }, I need to Filter Docs within a Set Date Range, But How do i Compare this? i need to filter like this,

I get System.InvalidOperationException: Parse({document}{EnrollmentDate}) is not supported. Error in SubFilter Line

CodePudding user response：

You have problem here when you want to do DateTime.Parse()

Can you post format of your string EnrollmentDate? And your variable date , is it only Date or DateTime?

This one maybe can help you here

Also, try to use

var subfilter = builder.Gte(x=>x.Y, Z)

CodePudding user response：

I think you need to achieve with MongoDB query as below:

{
  "$expr": {
    "$gte": [
      { "$toDate": "$EnrollmentDate" },
      date
    ]
  }
}

While I think it is not achievable with MongoDB .Net Driver LINQ syntax, you convert the query as BsonDocument:

var subfilter = new BsonDocument("$expr",
    new BsonDocument("$gte", 
        new BsonArray {
            new BsonDocument("$toDate", "$EnrollmentDate"),
            date
        }
    )
);

filter &= subfilter;