ConcurrencyToken

ConcurrencyToken.cs

public readonly struct ConcurrencyToken : IEquatable<ConcurrencyToken>
{
    public static readonly ConcurrencyToken None = new(Array.Empty<byte>());

    public byte[] Value { get; }

    public ConcurrencyToken(byte[] value)
    {
        Value = value ?? Array.Empty<byte>();
    }

    public ConcurrencyToken(string value)
    {
        Value = string.IsNullOrEmpty(value) ? Array.Empty<byte>() : Convert.FromHexString(value);
    }

    public override string ToString()
    {
        return Value != null ? Convert.ToHexString(Value) : null;
    }

    public override bool Equals(object obj)
    {
        return obj is ConcurrencyToken token && Equals(token);
    }

    public bool Equals(ConcurrencyToken other)
    {
        return EqualityComparer<byte[]>.Default.Equals(Value, other.Value);
    }

    public override int GetHashCode()
    {
        return Value.GetHashCode();
    }

    public static implicit operator byte[](ConcurrencyToken token) => token.Value;

    public static implicit operator string(ConcurrencyToken token) => token.ToString();

    public static implicit operator ConcurrencyToken(byte[] token) => new(token);

    public static implicit operator ConcurrencyToken(string token) => new(token);
}

ConcurrencyTokenTypeHandler.cs

public class ConcurrencyTokenTypeHandler : SqlMapper.TypeHandler<ConcurrencyToken>
{
    public override ConcurrencyToken Parse(object value)
    {
        if (value is string textToken)
            return new ConcurrencyToken(textToken);

        if (value is byte[] byteToken)
            return new ConcurrencyToken(byteToken);

        return ConcurrencyToken.None;
    }

    public override void SetValue(IDbDataParameter parameter, ConcurrencyToken value)
    {
        parameter.Value = value.Value;
        parameter.DbType = DbType.Binary;
    }
}