组合它们并确保始终正确的一种简单方法是：

string.Format("{0}/{1}", Url1.Trim('/'), Url2);

我们使用以下简单的助手方法将任意数量的URL部分连接在一起：

public static string JoinUrlParts(params string[] urlParts)
{
    return string.Join("/", urlParts.Where(up => !string.IsNullOrEmpty(up)).ToList().Select(up => up.Trim('/')).ToArray());
}

注意，它不支持'..//something/page.htm'样式的相对URL！

根据您提供的示例URL，我将假设您希望组合与站点相关的URL。

基于这一假设，我将提出这个解决方案，作为对您的问题的最恰当的回答：“Path.Combine很方便，在URL框架中有类似的功能吗？”

由于URL框架中有一个类似的函数，我建议正确的方法是：“VirtualPathUtility.Compine”方法。下面是MSDN参考链接：VirtualPathUtility.Combine方法

有一个警告：我认为这只适用于与您的网站相关的url（即，您不能使用它来生成指向另一个网站的链接。例如，var url=VirtualPathUtility.Combine（“www.google.com”，“accounts/widgets”）；）。

有趣的例子，Ryan，以函数的链接结尾。做得好。

一个建议Brian：如果您将此代码包装在函数中，则可能需要在TryCreate调用之前使用UriBuilder包装基URL。

否则，基本URL必须包含方案（其中UriBuilder将采用http://）。只是一个想法：

public string CombineUrl(string baseUrl, string relativeUrl) {
    UriBuilder baseUri = new UriBuilder(baseUrl);
    Uri newUri;

    if (Uri.TryCreate(baseUri.Uri, relativeUrl, out newUri))
        return newUri.ToString();
    else
        throw new ArgumentException("Unable to combine specified url values");
}

如果您不想拥有像Flurl这样的依赖项，可以使用它的源代码：

    /// <summary>
    /// Basically a Path.Combine for URLs. Ensures exactly one '/' separates each segment,
    /// and exactly on '&amp;' separates each query parameter.
    /// URL-encodes illegal characters but not reserved characters.
    /// </summary>
    /// <param name="parts">URL parts to combine.</param>
    public static string Combine(params string[] parts) {
        if (parts == null)
            throw new ArgumentNullException(nameof(parts));

        string result = "";
        bool inQuery = false, inFragment = false;

        string CombineEnsureSingleSeparator(string a, string b, char separator) {
            if (string.IsNullOrEmpty(a)) return b;
            if (string.IsNullOrEmpty(b)) return a;
            return a.TrimEnd(separator) + separator + b.TrimStart(separator);
        }

        foreach (var part in parts) {
            if (string.IsNullOrEmpty(part))
                continue;

            if (result.EndsWith("?") || part.StartsWith("?"))
                result = CombineEnsureSingleSeparator(result, part, '?');
            else if (result.EndsWith("#") || part.StartsWith("#"))
                result = CombineEnsureSingleSeparator(result, part, '#');
            else if (inFragment)
                result += part;
            else if (inQuery)
                result = CombineEnsureSingleSeparator(result, part, '&');
            else
                result = CombineEnsureSingleSeparator(result, part, '/');

            if (part.Contains("#")) {
                inQuery = false;
                inFragment = true;
            }
            else if (!inFragment && part.Contains("?")) {
                inQuery = true;
            }
        }
        return EncodeIllegalCharacters(result);
    }

    /// <summary>
    /// URL-encodes characters in a string that are neither reserved nor unreserved. Avoids encoding reserved characters such as '/' and '?'. Avoids encoding '%' if it begins a %-hex-hex sequence (i.e. avoids double-encoding).
    /// </summary>
    /// <param name="s">The string to encode.</param>
    /// <param name="encodeSpaceAsPlus">If true, spaces will be encoded as + signs. Otherwise, they'll be encoded as %20.</param>
    /// <returns>The encoded URL.</returns>
    public static string EncodeIllegalCharacters(string s, bool encodeSpaceAsPlus = false) {
        if (string.IsNullOrEmpty(s))
            return s;

        if (encodeSpaceAsPlus)
            s = s.Replace(" ", "+");

        // Uri.EscapeUriString mostly does what we want - encodes illegal characters only - but it has a quirk
        // in that % isn't illegal if it's the start of a %-encoded sequence https://stackoverflow.com/a/47636037/62600

        // no % characters, so avoid the regex overhead
        if (!s.Contains("%"))
            return Uri.EscapeUriString(s);

        // pick out all %-hex-hex matches and avoid double-encoding 
        return Regex.Replace(s, "(.*?)((%[0-9A-Fa-f]{2})|$)", c => {
            var a = c.Groups[1].Value; // group 1 is a sequence with no %-encoding - encode illegal characters
            var b = c.Groups[2].Value; // group 2 is a valid 3-character %-encoded sequence - leave it alone!
            return Uri.EscapeUriString(a) + b;
        });
    }

这里已经有了一些很好的答案。根据mdsharpe的建议，这里有一个扩展方法，当您想处理Uri实例时可以轻松使用：

using System;
using System.Linq;

public static class UriExtensions
{
    public static Uri Append(this Uri uri, params string[] paths)
    {
        return new Uri(paths.Aggregate(uri.AbsoluteUri, (current, path) => string.Format("{0}/{1}", current.TrimEnd('/'), path.TrimStart('/'))));
    }
}

使用示例：

var url = new Uri("http://example.com/subpath/").Append("/part1/", "part2").AbsoluteUri;

这将产生http://example.com/subpath/part1/part2

如果您希望使用字符串而不是Uris，那么以下操作也会产生相同的结果，只需根据您的需要进行调整即可：

public string JoinUriSegments(string uri, params string[] segments)
{
    if (string.IsNullOrWhiteSpace(uri))
        return null;

    if (segments == null || segments.Length == 0)
        return uri;

    return segments.Aggregate(uri, (current, segment) => $"{current.TrimEnd('/')}/{segment.TrimStart('/')}");
}

var uri = JoinUriSegements("http://example.com/subpath/", "/part1/", "part2");