MARKUS

    public class ConvertItem : IEquatable<ConvertItem>

        public bool Equals(ConvertItem other)

        {

            if (other is null)

                return false;

            return this.ConvertID == other.ConvertID && this.ProjectNumber == other.ProjectNumber;

        }

        public override bool Equals(object obj) => Equals(obj as ConvertItem);

        public override int GetHashCode()

        {

            var id = (ConvertID != null) ? ConvertID : "";

            var project = (ProjectNumber != null) ? ProjectNumber : ""; 

            return (id + project).GetHashCode();

        }