Fixed length with datetime decimal

[lw-schick]

Hi,

I use fixed length for attributes like following:

[FixedLengthFile]
public class MyFile
{
	[FixedLengthField(1, 1)]
	public string LineType { get; set; }

	[FixedLengthField(2, 13, Padding = Padding.Right, PaddingChar = ' ')]
	public string FormatVersion { get; set; }

        // @ToDo: What to write here? .... i miss DecimalPlaces = 2 ...
        [FixedLengthField(15, 15, PaddingChar = '0')]
	public decimal Amount { get; set; }
}

How can I use fixed length with decimal values? - the specification allows 2 decimal places. I need to specify that somewhere...

[lw-schick]

I discovered the code and I found the following solution:

[FixedLengthFile]
public class MyFile
{
    [FixedLengthField(1, 1)]
    public string LineType { get; set; }

    [FixedLengthField(2, 13, Padding = Padding.Right, PaddingChar = ' ')]
    public string FormatVersion { get; set; }

    [FixedLengthField(15, 15, PaddingChar = '0', Converter = typeof(ConverterDecimalTwoDigs))]
    public decimal Amount { get; set; }
}

internal class ConverterDecimalTwoDigs : ITypeConverter
{
    public bool CanConvertFrom(Type type)
    {
        return type == typeof(string);
    }

    public bool CanConvertTo(Type type)
    {
        return type == typeof(decimal);
    }

    public string ConvertToString(object source)
    {
        if (source.GetType() != typeof(decimal))
            throw new ArgumentException("Not expected type", nameof(source));

        return ((decimal)source).ToString("F2", CultureInfo.GetCultureInfo("de-DE"));
    }

    public object ConvertFromString(string source)
    {
        return decimal.Parse(source, NumberStyles.AllowDecimalPoint | NumberStyles.AllowLeadingSign, CultureInfo.GetCultureInfo("de-DE"));
    }
}

In my eyes, that is ugly. Would be nice to have another possibility to do this f.e. with DecimalPlaces or something else. But that's just my view, maybe there is a reason to do this like that...

At least, I would wish to see this in a FAQ section or somewhere else. The parameter Convert is not documented.

[OpenSpacesAndPlaces]

@lw-schick

Did you see this working, or is this just a code mock-out?

In my case "ConvertToString" is never fired, and looking at the source code there doesn't appear to be any calls to "ConvertToString".

[lw-schick]

Yes, this source code worked for me.

The function ConvertToString is implemented because it's part of the ITypeConverter interface. In my implementation, I only needed an implementation for the type decimal so I didn't implement it e.g. for float values. I know when you would implement it into a library you should support more types...
I used it here just to give an example how it is currently possible.

The point of this issue is that there is no support to define the number of decimal places via a parameter, so I would have to build an extra class when I need support for a fixed-point value with 5 decimal places after the point (e.g. 12345.67892).