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Asked: 2020-04-29 16:04:37 +0800 CST 2020-04-29 16:04:37 +0800 CST

Compare month in Linq select

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I need to compare the date only those that are in the month of the system and for this I make the following query:

                        var lstConcepto = (from m in context.SMT_CONCEPTOBASICO
                                       where m.CODIGOENTIDAD.Contains(getCodEntidad) 
                                       && m.FECHAINICIAL == ConceptoTo.FechaInicial 
                                       && m.FECHASISTEMA == ConceptoTo.FechaSistema.Month
                                       && !m.VALORALFANUMERICO.Contains("Total")
                                       select m).ToList();

I can't find a way to make m.SYSTEMDATE.MONTH the date of the object.

&& m.DATESYSTEM == ConceptTo.DateSystem.Month Here I get an error comparing datetime and int... how do I convert m.DATESYSTEM In month??

UPDATE the option of m.SYSTEMDATE.Month throws error as indicated in the image enter image description here

c#

2 Answers

  1. Best Answer

    The problem is that SYSTEMDATE is of type Nullable. That's why in the error it appears as DateTime?with the ?at the end.

    To read the value you must do it like this:

    m.FECHASISTEMA?.Month

    C# Nullable Reference

    Update:

    Create a variable and store the date value there to use in the query:

    var lstConcepto = (from m in context.SMT_CONCEPTOBASICO
     let fechaSistema = m.FECHASISTEMA.HasValue ? m.FECHASISTEMA.Value.Month : 0
     where m.CODIGOENTIDAD.Contains(getCodEntidad) 
     && m.FECHAINICIAL == ConceptoTo.FechaInicial 
     && fechaSistema == ConceptoTo.FechaSistema.Month
     && !m.VALORALFANUMERICO.Contains("Total")
     select m).ToList();
    • 1

  2. Whenever you can m.FECHASISTEMAmake DateTimethe comparison in the following way

    && m.FECHASISTEMA.Date.Month == ConceptoTo.FechaSistema.Month

    So yes, your code should be

    var lstConcepto = (from m in context.SMT_CONCEPTOBASICO
    where m.CODIGOENTIDAD.Contains(getCodEntidad) 
    && m.FECHAINICIAL == ConceptoTo.FechaInicial 
    && m.FECHASISTEMA.Date.Month == ConceptoTo.FechaSistema.Month
    && !m.VALORALFANUMERICO.Contains("Total")
    select m).ToList();
    • 0