Support fixed width parsing about csvhelper

[JoshClose]

Hmm... I think I would create a new parser for this. Parsing will be completely different. Writing will also be different, so I may have to abstract some of the writing stuff out too.

[paulduran]

@roryprimrose I think you'd be better off going with something like FileHelpers for fixed width file parsing. It already supports fixed width files pretty well.

[JoshClose]

I think there would be too many things that need to be added here for this to work properly. There would need to be a FixedWidthParser written. The property configurations would need at least the width set on them. This will muddy up the api. I think creating a whole new library that works with fixed width files is a better idea.

If that does happen and there is enough overlap in the reader and writer (i.e. auto class generation), maybe something could be abstracted out to be used in both libraries.

Right now this is not something I'm going to pursue.

[JoshClose]

I'm thinking I may add this to version 3.0.

[dmitry-azaraev]

@JoshClose I'm add ability of writing fixed-length fields, implementation now https://github.com/dmitry-azaraev/CsvHelper/tree/feature/writing-fixed-length-records .

It is actually do next things:

• Allow use empty delimeter. (Alternatively it is enough to make own CsvSerializer and do not emit delimeters).
• (Not directly related): Constants uses type converters. Current versions falls on Map().Constant(123). I'm fix it to always invoke type converters even for constants.
• Allow configure CsvPropertyMap Width, Align and AlignErrorMode for writing fixed-length fields.
• Added some tests about using width, align and error mode.

Basic idea of usage is:

    // configure 
    configuration.Delimiter = "";
    configuration.QuoteNoFields = true;
    configuration.HasHeaderRecord = false;

    // in map, define mappings
    Map(m => m.Id).Width(5);
    // or 
    Map(m => m.Id).Width(5, CsvAlign.Right);  // will pad spaces from left
    // or
    Map(m => m.Id).Width(5, CsvAlign.Right, CsvAlignErrorMode.Throw);  // will throw if field is not fit in space

Even while it is only supports writing, i'm found that it is simpler keep using one CsvHelper because when i'm write files, i'm use same fluent mapping syntax, reuse formats / etc. Do you like something like this?

And can i'm (we) count to have similar functionality in nearest future. I.e. what i'm should do to have PR been accepted?

[JoshClose]

This issue was moved to CsvHelperContrib/CsvHelperContrib#2

[niemyjski]

+1