How to set default value

Question

I am trying to parse a csv file using csv helper

this is my maping class

sealed class CSVFileDefinitionMapFinal : CsvClassMap<CSVFileDefinitionFinal>
{ 
    public CSVFileDefinitionMapFinal()
    {
        Map(m => m.FARM_ID).Name("FRM_ID");
    }
}

this is my item class

class CSVFileDefinitionFinal
{
    public int FARM_ID { get; set; }
}

the problem is that the FRM_ID in the csv may hav null. so when I do the mappign above, I have an exception that null can't be transfer to integer. I am asking about if there is a way to try and catch that and set the value to -10 when it is null.

the try and catch should be in the maping class, but I couldn't know what to do after catching the exception. in other words, i couldn't know how to set default value to the maping object

I believe he means `default`. I edited the question to change static to default. — Josh Close, Oct 01 '14 at 21:00

Marcel N. · Answer 1 · 2014-08-10T09:30:54.870

4

You can make that property nullable and not-automatic:

class CSVFileDefinitionFinal
{
    private int _farmId;

    public int? FARM_ID
    {
        get { return _farmId; }
        set { _farmId = value == null ? -10 : value.Value; }
    }
}

Note that you need to define a private int _farmId member in that class.

edited Aug 10 '14 at 09:30

answered Aug 10 '14 at 09:18

Marcel N.

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is the name `_farmId` necessery or I can change it to `myFarmID` ? – Anastasie Laurent Aug 10 '14 at 09:23
@AnastasieLaurent: You can change it to whatever you need. – Marcel N. Aug 10 '14 at 09:25
there are two errrors. 1 the semicolon after the `get` block 2 the can't explicity change `int?` to `int` – Anastasie Laurent Aug 10 '14 at 09:29
@AnastasieLaurent: See update. Not sure about the second error. When do you get that? – Marcel N. Aug 10 '14 at 09:31
after your update `value.Value` the syntax error gone. now let me test the application to see if the results are correct. +1 – Anastasie Laurent Aug 10 '14 at 09:32
I noticed something. the file is `xlsx` not `csv` :( so is the reading approach the same? or not? – Anastasie Laurent Aug 10 '14 at 09:46
@AnastasieLaurent: Not sure about that, since it depends on what CsvHelper can do. However, as long as it can deserialize to object the property will still work. – Marcel N. Aug 10 '14 at 09:52
your code works when there are null values, but through exception when the value are empty. can you modify your code to deal with empty values please? – Anastasie Laurent Aug 10 '14 at 09:55
@AnastasieLaurent: I'm afraid that is also about CsvHelper and the conversion should happen way before the value reaches the property. After a short search turns out you can use this: http://stackoverflow.com/questions/13058269/using-csvhelper-can-i-translate-white-space-to-a-nullable – Marcel N. Aug 10 '14 at 10:02
`set { _farmId = value ?? -10; }` This way is tidy and simple. – Poy Chang Mar 11 '22 at 01:05

score 4 · Answer 2 · answered Oct 01 '14 at 20:57

4

You can just add a default to the mapping.

Map(m => m.FARM_ID).Name("FRM_ID").Default( -10 );

answered Oct 01 '14 at 20:57

Josh Close

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How to set default value

2 Answers2