Pekspro.DataAnnotationValuesExtractor

RSCG – Pekspro.DataAnnotationValuesExtractor    

Generates typed constants from DataAnnotations attributes ([Range], [StringLength], [Required], [Display])

at compile time — no reflection needed to read annotation values.

How to use

1. Decorate your model with standard DataAnnotations:

“`charp

partial class Person

{

[Display(Name = “First name”)]

[StringLength(100, MinimumLength = 3)]

public string? FirstName { get; set; }

[Range(18, 200)]

public int Age { get; set; }

}

“`

2. Declare a partial extractor class targeting the model:

“`charp

[DataAnnotationValuesOptions(StringLength = true, Range = true, Required = true, Display = true)]

[DataAnnotationValuesToGenerate(typeof(Person))]

partial class Values { }

“`

3. Access generated constants:

“`charp

Console.WriteLine(Person.Annotations.Age.Minimum); // 18

Console.WriteLine(Person.Annotations.FirstName.MinimumLength); // 3

Console.WriteLine(Person.Annotations.FirstName.MaximumLength); // 100

“`

You can use for Reusing DataAnnotation constraint values (min/max lengths, ranges) in UI or validation logic

without duplicating magic numbers or using reflection.

This is how you can use Pekspro.DataAnnotationValuesExtractor .

The code that you start with is

<project sdk="Microsoft.NET.Sdk">

  <propertygroup>
    <outputtype>Exe</outputtype>
    <targetframework>net10.0</targetframework>
    <implicitusings>enable</implicitusings>
    <nullable>enable</nullable>
  </propertygroup>

  <itemgroup>
    <packagereference version="1.0.0" include="Pekspro.DataAnnotationValuesExtractor">
  </packagereference>
	<propertygroup>
		<emitcompilergeneratedfiles>true</emitcompilergeneratedfiles>
		<compilergeneratedfilesoutputpath>$(BaseIntermediateOutputPath)\GX</compilergeneratedfilesoutputpath>
	</propertygroup>
</itemgroup>

The code that you will use is

// See https://aka.ms/new-console-template for more information
using Attr;

Console.WriteLine(Person.Annotations.Age.Minimum);
Console.WriteLine(Person.Annotations.FirstName.MinimumLength);
Console.WriteLine(Person.Annotations.FirstName.MaximumLength);

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Text;

namespace Attr;

partial class Person
{
    [Display(Name = "First name")]
    [Required]
    [StringLength(100,MinimumLength =3)]
    public string? FirstName { get; set; }

    [Required]
    [Range(18, 200)]
    public int Age { get; set; }
}

using Pekspro.DataAnnotationValuesExtractor;

namespace Attr;


[DataAnnotationValuesOptions(StringLength = true, Range = true, Required = true, Display = true)]
[DataAnnotationValuesToGenerate(typeof(Person))]
partial  class Values
{
}

   The code that is generated is

//---------------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by the Pekspro.DataAnnotationValuesExtractor source generator.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//---------------------------------------------------------------------------------------

#nullable enable

namespace Attr
{
    /// <summary>
    /// Data annotation values for Person.
    /// </summary>
    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Pekspro.DataAnnotationValuesExtractor", "1.0.0")]
    public partial class Person
    {
        /// <summary>
        /// Data annotation values.
        /// </summary>
        public static class Annotations
        {
            /// <summary>
            /// Data annotation values for FirstName.
            /// </summary>
            public static class FirstName
            {
                /// <summary>
                /// Maximum length for FirstName.
                /// </summary>
                public const int MaximumLength = 100;

                /// <summary>
                /// Minimum length for FirstName.
                /// </summary>
                public const int MinimumLength = 3;

                /// <summary>
                /// Indicates whether FirstName is required.
                /// </summary>
                public const bool IsRequired = true;

                /// <summary>
                /// Display attribute values for FirstName.
                /// </summary>
                public static class Display
                {
                    /// <summary>
                    /// Display name for FirstName.
                    /// </summary>
                    public const string? Name = "First name";

                    /// <summary>
                    /// Short display name for FirstName.
                    /// </summary>
                    public const string? ShortName = null;

                    /// <summary>
                    /// Description for FirstName.
                    /// </summary>
                    public const string? Description = null;
                }
            }

            /// <summary>
            /// Data annotation values for Age.
            /// </summary>
            public static class Age
            {
                /// <summary>
                /// Minimum value for Age.
                /// </summary>
                public const int Minimum = 18;

                /// <summary>
                /// Maximum value for Age.
                /// </summary>
                public const int Maximum = 200;

                /// <summary>
                /// Indicates whether the minimum value for Age is exclusive.
                /// </summary>
                public const bool MinimumIsExclusive = false;

                /// <summary>
                /// Indicates whether the maximum value for Age is exclusive.
                /// </summary>
                public const bool MaximumIsExclusive = false;

                /// <summary>
                /// Indicates whether Age is required.
                /// </summary>
                public const bool IsRequired = true;
            }
        }
    }
}

Code and pdf at

https://ignatandrei.github.io/RSCG_Examples/v2/docs/Pekspro.DataAnnotationValuesExtractor