// System.Collections.Specialized.NameValueCollection
public virtual string Get(string name)
{
	ArrayList list = (ArrayList)base.BaseGet(name);
	return NameValueCollection.GetAsOneString(list);
}

private static string GetAsOneString(ArrayList list)
{
	int num = (list != null) ? list.Count : 0;
	if (num == 1)
	{
		return (string)list[0];
	}
	if (num > 1)
	{
		StringBuilder stringBuilder = new StringBuilder((string)list[0]);
		for (int i = 1; i < num; i++)
		{
			stringBuilder.Append(',');
			stringBuilder.Append((string)list[i]);
		}
		return stringBuilder.ToString();
	}
	return null;
}

// System.Collections.Specialized.NameObjectCollectionBase
private Hashtable _entriesTable;

protected object BaseGet(string name)
{
	NameObjectCollectionBase.NameObjectEntry nameObjectEntry = this.FindEntry(name);
	if (nameObjectEntry == null)
	{
		return null;
	}
	return nameObjectEntry.Value;
}

private NameObjectCollectionBase.NameObjectEntry FindEntry(string key)
{
	if (key != null)
	{
		return (NameObjectCollectionBase.NameObjectEntry)this._entriesTable[key];
	}
	return this._nullKeyEntry;
}

NameValueCollection.Get()

C#