IValidable

IValidable is an interface for classes whose state can be validated.

/// <summary>Interface for classes whose state can be verified to be valid.</summary>
public interface IValidable
{
    /// <summary>Check object for invalid state causes.</summary>
    /// <returns>Return validation messages.</returns>
    IEnumerable<IMessage> Validate();
}

.Validate() returns all validation messages.

MyClass myClass = new MyClass(null, null);
IEnumerable<IMessage> messages = myClass.Validate();
WriteLine(string.Join(", ", messages)); // Parameter 'Name' cannot be null., Parameter 'Label' cannot be null.

.ValidateSingle() returns a single validation message, prioritizing critical ones.

MyClass myClass = new MyClass(null, null);
IMessage message = myClass.ValidateSingle();
WriteLine(message); // Parameter 'Name' cannot be null.

.AssertGood() asserts that all validation messages are Good. If not ValidationException is thrown.

MyClass myClass = new MyClass("ABC", "Hello").AssertGood();

.AssertNotBad() asserts that all validation codes are Good or Uncertain. If not ValidationException is thrown.

try
{
    MyClass myClass = new MyClass(null, null).AssertNotBad();
}
catch (Exception e) when (e.HResult == SystemMessages.ArgumentNull.WithParamName.HResult)
{
    // "Avalanche.Message.ValidationException:  (Parameter 'Name' cannot be null.) (Parameter 'Label' cannot be null.)"
    // "   at validable.Run() in validable.cs:line 41"
    WriteLine(e);
}

IValidable implementation returns messages as validation codes. See mscorlib.dll for scraped Argument, ArgumentNull and ArgumentOutOfRange validation messages.

public class MyClass : IValidable
{
    public string? Name;
    public string? Label;

    public MyClass(string? name, string? label)
    {
        Name = name;
        Label = label;
    }

    /// <summary>Validate class</summary>
    /// <returns>Return validation errors.</returns>
    public IEnumerable<IMessage> Validate()
    {
        // Place codes here
        StructList2<IMessage> codes = new();
        // Validate 'Name' not null
        if (Name == null) codes.Add( SystemMessages.ArgumentNull.WithParamName.NameOf(Name) );
        // Validate 'Label' not null
        if (Label == null) codes.Add( SystemMessages.ArgumentNull.WithParamName.NameOf(Label) );
        // Good
        if (codes.Count == 0) codes.Add(HResult.S_OK.New());
        // Return
        return codes.ToArray(); // If empty returns singleton T[0].
    }
}

Full Example

Full example

using System;
using System.Collections.Generic;
using Avalanche.Utilities;
using Avalanche.Message;
using static System.Console;
using Avalanche.StatusCode;

class validation
{
    public static void Run()
    {
        {
            // <01>
            MyClass myClass = new MyClass(null, null);
            IMessage message = myClass.ValidateSingle();
            WriteLine(message); // Parameter 'Name' cannot be null.
            // </01>
        }
        {
            // <02>
            MyClass myClass = new MyClass(null, null);
            IEnumerable<IMessage> messages = myClass.Validate();
            WriteLine(string.Join(", ", messages)); // Parameter 'Name' cannot be null., Parameter 'Label' cannot be null.
            // </02>
        }
        {
            // <03>
            MyClass myClass = new MyClass("ABC", "Hello");
            IMessage message = myClass.ValidateSingle();
            WriteLine(message); // "Operation successful"
            // </03>
        }
        {
            // <11>
            MyClass myClass = new MyClass("ABC", "Hello").AssertGood();
            // </11>
        }
        // <12>
        try
        {
            MyClass myClass = new MyClass(null, null).AssertNotBad();
        }
        catch (Exception e) when (e.HResult == SystemMessages.ArgumentNull.WithParamName.HResult)
        {
            // "Avalanche.Message.ValidationException:  (Parameter 'Name' cannot be null.) (Parameter 'Label' cannot be null.)"
            // "   at validable.Run() in validable.cs:line 41"
            WriteLine(e);
        }
        // </12>
    }

    // <90>
    public class MyClass : IValidable
    {
        public string? Name;
        public string? Label;

        public MyClass(string? name, string? label)
        {
            Name = name;
            Label = label;
        }

        /// <summary>Validate class</summary>
        /// <returns>Return validation errors.</returns>
        public IEnumerable<IMessage> Validate()
        {
            // Place codes here
            StructList2<IMessage> codes = new();
            // Validate 'Name' not null
            if (Name == null) codes.Add( SystemMessages.ArgumentNull.WithParamName.NameOf(Name) );
            // Validate 'Label' not null
            if (Label == null) codes.Add( SystemMessages.ArgumentNull.WithParamName.NameOf(Label) );
            // Good
            if (codes.Count == 0) codes.Add(HResult.S_OK.New());
            // Return
            return codes.ToArray(); // If empty returns singleton T[0].
        }
    }
    // </90>
}