How to validate a .csv file before storage in C#?

Question

I have some .csv files which I am parsing before storing in database.

I would like to make application more robust, and perform validation upon the .csv files before

Answer 1

Probably you should take a look to http://www.codeproject.com/Articles/9258/A-Fast-CSV-Reader

We have been using this in our projects, its quite robust and does what it says.

Answer 2

adrianm and Nipun Ambastha

Thank you for your response to my question.

I solved my problem by writing a solution to validate my .csv file myself.

It's quite possible a more elegant solution could be made by making use of adrianm's code, but I didn't do that, but I am encouraging to give adrianm's code a look.

I am validating the list below.

• Empty file new FileInfo(dto.AbsoluteFileName).Length == 0

• Wrong formatting of file lines. string[] items = line.Split('\t'); if (items.Count() == 20)

• Wrong datatype in line fields. int number; bool isNumber = int.TryParse(dataRow.ItemArray[0].ToString(), out number);

• Missing required line fields. if (dataRow.ItemArray[4].ToString().Length < 1)

To work through the contents of the .csv file I based my code on this code example:

http://bytes.com/topic/c-sharp/answers/256797-reading-tab-delimited-file

Answer 3

I do like this:

Create a class to hold each parsed line with expected type

 internal sealed class Record {
     public int Field1 { get; set; }
     public DateTime Field2 { get; set; }
     public decimal? PossibleEmptyField3 { get; set; }
     ...
 }

Create a method that parses a line into the record

public Record ParseRecord(string[] fields) {
    if (fields.Length < SomeLineLength)
        throw new MalformadLineException(...)

    var record = new Record();

    record.Field1 = int.Parse(fields[0], NumberFormat.None, CultureInvoice.InvariantCulture);
    record.Field2 = DateTime.ParseExact(fields[1], "yyyyMMdd", CultureInvoice.InvariantCulture);
    if (fields[2] != "")
        record.PossibleEmptyField3 = decimal.Parse(fields[2]...)

    return record;
}

Create a method parsing the entire file

public List<Record> ParseStream(Stream stream) {
    var tfp = new TextFileParser(stream);

    ...
    try {
        while (!tfp.EndOfData) {
            records.Add(ParseRecord(tfp.ReadFields());
        }
    }
    catch (FormatException ex) {
        ... // show error
    }
    catch (MalformadLineException ex) {
        ... // show error
    }

    return records;
}

And then I create a number of methods validating the fields

public void ValidateField2(IEnumerable<Record> records) {
    foreach (var invalidRecord in records.Where(x => x.Field2 < DateTime.Today))
       ... // show error
}

I have tried various tools but since the pattern is straight forward they don't help much. (You should use a tool to split the line into fields)

Answer 4

You can use FileHelpers a free/open source .Net library to deal with CSV and many other file formats.