System.Net.Http.Headers.NameValueHeaderValue.Find C# (CSharp) Method

        internal static NameValueHeaderValue Find(ObjectCollection<NameValueHeaderValue> values, string name)
        {
            Debug.Assert((name != null) && (name.Length > 0));

            if ((values == null) || (values.Count == 0))
            {
                return null;
            }

            foreach (var value in values)
            {
                if (string.Equals(value.Name, name, StringComparison.OrdinalIgnoreCase))
                {
                    return value;
                }
            }
            return null;
        }

        internal static void SetQuality(ObjectCollection <NameValueHeaderValue> parameters, double?value)
        {
            Debug.Assert(parameters != null);

            NameValueHeaderValue?qualityParameter = NameValueHeaderValue.Find(parameters, qualityName);

            if (value.HasValue)
            {
                // Note that even if we check the value here, we can't prevent a user from adding an invalid quality
                // value using Parameters.Add(). Even if we would prevent the user from adding an invalid value
                // using Parameters.Add() they could always add invalid values using HttpHeaders.AddWithoutValidation().
                // So this check is really for convenience to show users that they're trying to add an invalid
                // value.
                if ((value < 0) || (value > 1))
                {
                    throw new ArgumentOutOfRangeException(nameof(value));
                }

                string qualityString = ((double)value).ToString("0.0##", NumberFormatInfo.InvariantInfo);
                if (qualityParameter != null)
                {
                    qualityParameter.Value = qualityString;
                }
                else
                {
                    parameters.Add(new NameValueHeaderValue(qualityName, qualityString));
                }
            }
            else
            {
                // Remove quality parameter
                if (qualityParameter != null)
                {
                    parameters.Remove(qualityParameter);
                }
            }
        }