我创建了这个功能，可以让您的生活更轻松：

    /// <summary>
    /// The ultimate Path combiner of all time
    /// </summary>
    /// <param name="IsURL">
    /// true - if the paths are Internet URLs, false - if the paths are local URLs, this is very important as this will be used to decide which separator will be used.
    /// </param>
    /// <param name="IsRelative">Just adds the separator at the beginning</param>
    /// <param name="IsFixInternal">Fix the paths from within (by removing duplicate separators and correcting the separators)</param>
    /// <param name="parts">The paths to combine</param>
    /// <returns>the combined path</returns>
    public static string PathCombine(bool IsURL , bool IsRelative , bool IsFixInternal , params string[] parts)
    {
        if (parts == null || parts.Length == 0) return string.Empty;
        char separator = IsURL ? '/' : '\\';

        if (parts.Length == 1 && IsFixInternal)
        {
            string validsingle;
            if (IsURL)
            {
                validsingle = parts[0].Replace('\\' , '/');
            }
            else
            {
                validsingle = parts[0].Replace('/' , '\\');
            }
            validsingle = validsingle.Trim(separator);
            return (IsRelative ? separator.ToString() : string.Empty) + validsingle;
        }

        string final = parts
            .Aggregate
            (
            (string first , string second) =>
            {
                string validfirst;
                string validsecond;
                if (IsURL)
                {
                    validfirst = first.Replace('\\' , '/');
                    validsecond = second.Replace('\\' , '/');
                }
                else
                {
                    validfirst = first.Replace('/' , '\\');
                    validsecond = second.Replace('/' , '\\');
                }
                var prefix = string.Empty;
                if (IsFixInternal)
                {
                    if (IsURL)
                    {
                        if (validfirst.Contains("://"))
                        {
                            var tofix = validfirst.Substring(validfirst.IndexOf("://") + 3);
                            prefix = validfirst.Replace(tofix , string.Empty).TrimStart(separator);

                            var tofixlist = tofix.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);

                            validfirst = separator + string.Join(separator.ToString() , tofixlist);
                        }
                        else
                        {
                            var firstlist = validfirst.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);
                            validfirst = string.Join(separator.ToString() , firstlist);
                        }

                        var secondlist = validsecond.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);
                        validsecond = string.Join(separator.ToString() , secondlist);
                    }
                    else
                    {
                        var firstlist = validfirst.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);
                        var secondlist = validsecond.Split(new[] { separator } , StringSplitOptions.RemoveEmptyEntries);

                        validfirst = string.Join(separator.ToString() , firstlist);
                        validsecond = string.Join(separator.ToString() , secondlist);
                    }
                }
                return prefix + validfirst.Trim(separator) + separator + validsecond.Trim(separator);
            }
            );
        return (IsRelative ? separator.ToString() : string.Empty) + final;
    }

它适用于URL和普通路径。

用法：

    // Fixes internal paths
    Console.WriteLine(PathCombine(true , true , true , @"\/\/folder 1\/\/\/\\/\folder2\///folder3\\/" , @"/\somefile.ext\/\//\"));
    // Result: /folder 1/folder2/folder3/somefile.ext

    // Doesn't fix internal paths
    Console.WriteLine(PathCombine(true , true , false , @"\/\/folder 1\/\/\/\\/\folder2\///folder3\\/" , @"/\somefile.ext\/\//\"));
    //result : /folder 1//////////folder2////folder3/somefile.ext

    // Don't worry about URL prefixes when fixing internal paths
    Console.WriteLine(PathCombine(true , false , true , @"/\/\/https:/\/\/\lul.com\/\/\/\\/\folder2\///folder3\\/" , @"/\somefile.ext\/\//\"));
    // Result: https://lul.com/folder2/folder3/somefile.ext

    Console.WriteLine(PathCombine(false , true , true , @"../../../\\..\...\./../somepath" , @"anotherpath"));
    // Result: \..\..\..\..\...\.\..\somepath\anotherpath

Ryan Cook的答案与我的目标接近，可能更适合其他开发人员。然而，它在字符串的开头添加了http://，并且一般来说，它的格式比我想要的要多一些。

此外，对于我的用例，解析相对路径并不重要。

mdsharp的答案也包含了一个好主意的种子，尽管实际实现需要更多细节才能完成。这是一种充实它的尝试（我在生产中使用了这一点）：

C#

public string UrlCombine(string url1, string url2)
{
    if (url1.Length == 0) {
        return url2;
    }

    if (url2.Length == 0) {
        return url1;
    }

    url1 = url1.TrimEnd('/', '\\');
    url2 = url2.TrimStart('/', '\\');

    return string.Format("{0}/{1}", url1, url2);
}

VB.NET

Public Function UrlCombine(ByVal url1 As String, ByVal url2 As String) As String
    If url1.Length = 0 Then
        Return url2
    End If

    If url2.Length = 0 Then
        Return url1
    End If

    url1 = url1.TrimEnd("/"c, "\"c)
    url2 = url2.TrimStart("/"c, "\"c)

    Return String.Format("{0}/{1}", url1, url2)
End Function

这段代码通过了以下测试，恰好是在VB中：

<TestMethod()> Public Sub UrlCombineTest()
    Dim target As StringHelpers = New StringHelpers()

    Assert.IsTrue(target.UrlCombine("test1", "test2") = "test1/test2")
    Assert.IsTrue(target.UrlCombine("test1/", "test2") = "test1/test2")
    Assert.IsTrue(target.UrlCombine("test1", "/test2") = "test1/test2")
    Assert.IsTrue(target.UrlCombine("test1/", "/test2") = "test1/test2")
    Assert.IsTrue(target.UrlCombine("/test1/", "/test2/") = "/test1/test2/")
    Assert.IsTrue(target.UrlCombine("", "/test2/") = "/test2/")
    Assert.IsTrue(target.UrlCombine("/test1/", "") = "/test1/")
End Sub

所以我有另一种方法，类似于使用UriBuilder的每个人。

我不想拆分我的BaseUrl（它可以包含路径的一部分，例如。http://mybaseurl.com/dev/)正如javajavajavajava所做的那样。

下面的代码片段显示了代码+测试。

注意：此解决方案降低了主机并附加了一个端口。如果不需要这样做，可以通过例如利用UriBuilder的Uri属性来编写字符串表示。

  public class Tests
  {
         public static string CombineUrl (string baseUrl, string path)
         {
           var uriBuilder = new UriBuilder (baseUrl);
           uriBuilder.Path = Path.Combine (uriBuilder.Path, path);
           return uriBuilder.ToString();
         }

         [TestCase("http://MyUrl.com/", "/Images/Image.jpg", "http://myurl.com:80/Images/Image.jpg")]
         [TestCase("http://MyUrl.com/basePath", "/Images/Image.jpg", "http://myurl.com:80/Images/Image.jpg")]
         [TestCase("http://MyUrl.com/basePath", "Images/Image.jpg", "http://myurl.com:80/basePath/Images/Image.jpg")]
         [TestCase("http://MyUrl.com/basePath/", "Images/Image.jpg", "http://myurl.com:80/basePath/Images/Image.jpg")]
         public void Test1 (string baseUrl, string path, string expected)
         {
           var result = CombineUrl (baseUrl, path);

           Assert.That (result, Is.EqualTo (expected));
         }
  }

在Windows 10上使用.NET Core 2.1进行测试。

为什么这样做？

尽管Path.Combine将返回反斜杠（至少在Windows上），但UriBuilder在路径设置器中处理这种情况。

摘自https://github.com/dotnet/corefx/blob/master/src/System.Private.Uri/src/System/UriBuilder.cs（注意调用字符串。替换）

[AllowNull]
public string Path
{
      get
      {
          return _path;
      }
      set
      {
          if ((value == null) || (value.Length == 0))
          {
              value = "/";
          }
          _path = Uri.InternalEscapeString(value.Replace('\\', '/'));
          _changed = true;
      }
 }

这是最好的方法吗？

当然，这个解决方案非常自我描述（至少在我看来）。但是，您依赖的是.NETAPI中的未记录（至少我在快速谷歌搜索中没有发现任何内容）“功能”。这可能会随着将来的版本而改变，因此请将方法与测试结合起来。

中有测试https://github.com/dotnet/corefx/blob/master/src/System.Private.Uri/tests/FunctionalTests/UriBuilderTests.cs（Path_Get_Set），用于检查\是否正确转换。

附带说明：如果Uri将用于System.Uri构造函数，则也可以直接使用UriBuilder.Uri属性。

这是我的方法，我也会自己使用：

public static string UrlCombine(string part1, string part2)
{
    string newPart1 = string.Empty;
    string newPart2 = string.Empty;
    string seperator = "/";

    // If either part1 or part 2 is empty,
    // we don't need to combine with seperator
    if (string.IsNullOrEmpty(part1) || string.IsNullOrEmpty(part2))
    {
        seperator = string.Empty;
    }

    // If part1 is not empty,
    // remove '/' at last
    if (!string.IsNullOrEmpty(part1))
    {
        newPart1 = part1.TrimEnd('/');
    }

    // If part2 is not empty,
    // remove '/' at first
    if (!string.IsNullOrEmpty(part2))
    {
        newPart2 = part2.TrimStart('/');
    }

    // Now finally combine
    return string.Format("{0}{1}{2}", newPart1, seperator, newPart2);
}

我使用此代码来解决问题：

string[] brokenBaseUrl = Context.Url.TrimEnd('/').Split('/');
string[] brokenRootFolderPath = RootFolderPath.Split('/');

for (int x = 0; x < brokenRootFolderPath.Length; x++)
{
    //if url doesn't already contain member, append it to the end of the string with / in front
    if (!brokenBaseUrl.Contains(brokenRootFolderPath[x]))
    {
        if (x == 0)
        {
            RootLocationUrl = Context.Url.TrimEnd('/');
        }
        else
        {
            RootLocationUrl += String.Format("/{0}", brokenRootFolderPath[x]);
        }
    }
}

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;
        });
    }