System.ComponentModel.AttributeCollection.FromExisting C# (CSharp) Method

        public static AttributeCollection FromExisting(AttributeCollection existing, params Attribute[] newAttributes)
        {
            if (existing == null)
            {
                throw new ArgumentNullException("existing");
            }

            if (newAttributes == null)
            {
                newAttributes = new Attribute[0];
            }

            Attribute[] newArray = new Attribute[existing.Count + newAttributes.Length];
            int actualCount = existing.Count;
            existing.CopyTo(newArray, 0);

            for (int idx = 0; idx < newAttributes.Length; idx++)
            {
                if (newAttributes[idx] == null)
                {
                    throw new ArgumentNullException("newAttributes");
                }

                // We must see if this attribute is already in the existing
                // array.  If it is, we replace it.
                bool match = false;
                for (int existingIdx = 0; existingIdx < existing.Count; existingIdx++)
                {
                    if (newArray[existingIdx].TypeId.Equals(newAttributes[idx].TypeId))
                    {
                        match = true;
                        newArray[existingIdx] = newAttributes[idx];
                        break;
                    }
                }

                if (!match)
                {
                    newArray[actualCount++] = newAttributes[idx];
                }
            }

            // Now, if we collapsed some attributes, create a new array.
            //

            Attribute[] attributes = null;
            if (actualCount < newArray.Length)
            {
                attributes = new Attribute[actualCount];
                Array.Copy(newArray, 0, attributes, 0, actualCount);
            }
            else
            {
                attributes = newArray;
            }

            return new AttributeCollection(attributes);
        }