private Expression ConvertExpression(Type typeToConvertTo, Expression recordColumnAccessor,
MappableAttribute mappableAttribute)
{
return(mappableAttribute.UseCustomConvertor
? BuildCustomConvertorExpression(recordColumnAccessor, typeToConvertTo)
: Expression.Convert(recordColumnAccessor, typeToConvertTo));
}
private static IndexExpression ReaderColumnAccessor(Expression dataReaderParameter,
PropertyInfo indexerProperty,
MappableAttribute mappableAttribute)
{
return(Expression.MakeIndex(dataReaderParameter, indexerProperty,
new[] { Expression.Constant(mappableAttribute.ReaderColumnName) }));
}
private static MethodCallExpression GetOrdinalExpression(Expression dataReaderParameter,
MappableAttribute mappableAttribute)
{
var getOrdinalMethod = typeof(IDataRecord).GetMethod("GetOrdinal");
return(Expression.Call(dataReaderParameter, getOrdinalMethod,
Expression.Constant(mappableAttribute.ReaderColumnName)));
}
private static ConditionalExpression NullableConvertExpression(Expression dataReaderParameter,
MappableAttribute mappableAttribute, PropertyInfo property, Expression convertExpression)
{
var getOrdinalExpression = GetOrdinalExpression(dataReaderParameter, mappableAttribute);
var isDbNullMethodExpression = IsDbNullExpression(dataReaderParameter, getOrdinalExpression);
var ifNullThenNullElseValueExpression = Expression.Condition(isDbNullMethodExpression,
Expression.Constant(null, property.PropertyType), convertExpression);
return(ifNullThenNullElseValueExpression);
}