如何使 Uri.EscapeDataString 符合 RFC 3986

Uri 类默认为 RFC 2396。对于 OpenID 和 OAuth，我需要与 RFC 3986 一致的 Uri 转义。

来自System.Uri 类文档 http://msdn.microsoft.com/en-us/library/system.uri.aspx:

默认情况下，URI 中的任何保留字符都会根据 RFC 2396 进行转义。如果启用国际资源标识符或国际域名解析，则此行为会发生变化，在这种情况下，URI 中的保留字符会根据 RFC 3986 和 RFC 3987 进行转义。

该文档还指出，激活此 IRI 模式以及 RFC 3986 行为意味着将 uri 部分元素添加到 machine.config 并将其添加到您的 app/web.config 文件中：

<configuration>
  <uri>
  <idn enabled="All" />
  <iriParsing enabled="true" />
  </uri>
</configuration>

但无论这是否存在于 .config 文件中，我都会在 .NET 3.5 SP1 应用程序中得到相同的（非 3986）转义行为。我还需要做什么才能获得Uri.EscapeDataString使用 RFC 3986 规则？（具体来说，转义 RFC 中定义的保留字符）

由于无法让 Uri.EscapeDataString 采取 RFC 3986 行为，我编写了自己的符合 RFC 3986 的转义方法。它利用 Uri.EscapeDataString，然后将转义“升级”为 RFC 3986 合规性。

/// <summary>
/// The set of characters that are unreserved in RFC 2396 but are NOT unreserved in RFC 3986.
/// </summary>
private static readonly string[] UriRfc3986CharsToEscape = new[] { "!", "*", "'", "(", ")" };

/// <summary>
/// Escapes a string according to the URI data string rules given in RFC 3986.
/// </summary>
/// <param name="value">The value to escape.</param>
/// <returns>The escaped value.</returns>
/// <remarks>
/// The <see cref="Uri.EscapeDataString"/> method is <i>supposed</i> to take on
/// RFC 3986 behavior if certain elements are present in a .config file.  Even if this
/// actually worked (which in my experiments it <i>doesn't</i>), we can't rely on every
/// host actually having this configuration element present.
/// </remarks>
internal static string EscapeUriDataStringRfc3986(string value) {
    // Start with RFC 2396 escaping by calling the .NET method to do the work.
    // This MAY sometimes exhibit RFC 3986 behavior (according to the documentation).
    // If it does, the escaping we do that follows it will be a no-op since the
    // characters we search for to replace can't possibly exist in the string.
    StringBuilder escaped = new StringBuilder(Uri.EscapeDataString(value));

    // Upgrade the escaping to RFC 3986, if necessary.
    for (int i = 0; i < UriRfc3986CharsToEscape.Length; i++) {
        escaped.Replace(UriRfc3986CharsToEscape[i], Uri.HexEscape(UriRfc3986CharsToEscape[i][0]));
    }

    // Return the fully-RFC3986-escaped string.
    return escaped.ToString();
}