JoinAttributes.cs

using System.Collections;
using System.Xml;
 
namespace Waher.Content.Semantic.Model
{
    public class JoinAttributes : IEnumerable
    {
        private readonly XmlAttributeCollection attributes1;
        private readonly XmlAttributeCollection attributes2;
 
        public JoinAttributes(XmlAttributeCollection Attributes1, XmlAttributeCollection Attributes2)
        {
            this.attributes1 = Attributes1;
            this.attributes2 = Attributes2;
        }
 
        public IEnumerator GetEnumerator()
        {
            return new JoinedAttributesEnumerator(this.attributes1.GetEnumerator(),
                this.attributes2.GetEnumerator());
        }
 
        private class JoinedAttributesEnumerator : IEnumerator
        {
            private readonly IEnumerator enumerator1;
            private readonly IEnumerator enumerator2;
            private bool first;
 
            public JoinedAttributesEnumerator(IEnumerator e1, IEnumerator e2)
            {
                this.enumerator1 = e1;
                this.enumerator2 = e2;
                this.first = true;
            }
 
            public object Current
            {
                get
                {
                    if (this.first)
                        return (XmlAttribute)this.enumerator1.Current;
                    else
                        return (XmlAttribute)this.enumerator2.Current;
                }
            }
 
            public bool MoveNext()
            {
                if (this.first)
                {
                    if (this.enumerator1.MoveNext())
                        return true;
                    else
                        this.first = false;
                }
 
                return this.enumerator2.MoveNext();
            }
 
            public void Reset()
            {
                this.enumerator1.Reset();
                this.enumerator2.Reset();
 
                this.first = true;
            }
        }
    }
}