c# get and set accessors datetime

Question

I am receiving unreachable code detected in my properties. This worked for regular string fields but not for DateTime data type.

private DateTime m_RenewalDate;
    public DateTime M_RenewalDate
            {
                get { return m_RenewalDate != null ? m_RenewalDate : DateTime.MinValue; }
                set { m_RenewalDate = value; }
            }

this is my sqldatareader

reader.GetDateTime(reader.GetOrdinal("M_RENEWALDATE"))

Answer 1

DateTime is a value type, and can not be null. Therefore, the code in the getter is unreachable:

return m_RenewalDate != null ? // always evaluates to true
       m_RenewalDate :         // and therefore always returns this
       DateTime.MinValue;      // The code never hits this case.

If your field in the database can be null, perhaps you want to declare the property as a nullable DateTime: DateTime? .

Answer 2

DateTime is a value type and cannot be null. To compare with a null value in the database, use DBNull.Value

Answer 3

As driis said in his answer, m_RenewalDate == null is always false as DateTime is a value type and things declared to be value types cannot be null.

To have the get the behavior of returning DateTime.MinValue from M_RenewalDate in the case that M_RENEWALDATE is null your reader code should look more like this

object renewalDate = reader.GetValue(reader.GetOrdinal("M_RENEWALDATE"));

if (Equals(renewalDate, DBNull.Value))
{
    yourObject.M_RenewalDate = DateTime.MinValue;
}
else
{
    yourObject.M_RenewalDate = (DateTime) renewalDate;
}