Question

例如，我该如何制作

"C:\RootFolder\SubFolder\MoreSubFolder\LastFolder\SomeFile.txt"

相对于此文件夹

"C:\RootFolder\SubFolder\"

如果预期结果是

"MoreSubFolder\LastFolder\SomeFile.txt"

Answer 1

是的，您可以这样做，很容易，将您的路径视为URI ：

Uri fullPath = new Uri(@"C:\RootFolder\SubFolder\MoreSubFolder\LastFolder\SomeFile.txt", UriKind.Absolute);
Uri relRoot = new Uri(@"C:\RootFolder\SubFolder\", UriKind.Absolute);

string relPath = relRoot.MakeRelativeUri(fullPath).ToString();
// relPath == @"MoreSubFolder\LastFolder\SomeFile.txt"

Answer 2

在您的示例中，它只是absPath.Substring(relativeTo.Length)。

更详细的示例需要从relativeTo返回几个级别，如下所示：

"C:\RootFolder\SubFolder\MoreSubFolder\LastFolder\SomeFile.txt"
"C:\RootFolder\SubFolder\Sibling\Child\"

制作相对路径的算法如下所示：

删除最长的公共前缀（在本例中为"C:\RootFolder\SubFolder\"）
计算relativeTo中的文件夹数量（在这种情况下，它是2："Sibling\Child\"）
为每个剩余文件夹插入..\
与后缀删除后的其余绝对路径连接

最终结果如下：

"..\..\MoreSubFolder\LastFolder\SomeFile.txt"

Answer 3

这是我的5美分，没有为此目的使用任何特殊的Url类。

在以下git存储库中搜索makeRelative：https://github.com/tapika/syncProj/blob/8ea41ebc11f538a22ed7cfaf59a8b7e0b4c3da37/syncProj.cs#L1685

（固定版一次冻结，分别搜索最新版本）

如果有错误，我会修复错误。

以下是上述链接中相同代码的副本：

/// <summary>
/// Rebases file with path fromPath to folder with baseDir.
/// </summary>
/// <param name="_fromPath">Full file path (absolute)</param>
/// <param name="_baseDir">Full base directory path (absolute)</param>
/// <returns>Relative path to file in respect of baseDir</returns>
static public String makeRelative(String _fromPath, String _baseDir)
{
    String pathSep = "\\";
    String fromPath = Path.GetFullPath(_fromPath);
    String baseDir = Path.GetFullPath(_baseDir);            // If folder contains upper folder references, they gets lost here. "c:\test\..\test2" => "c:\test2"

    String[] p1 = Regex.Split(fromPath, "[\\\\/]").Where(x => x.Length != 0).ToArray();
    String[] p2 = Regex.Split(baseDir, "[\\\\/]").Where(x => x.Length != 0).ToArray();
    int i = 0;

    for (; i < p1.Length && i < p2.Length; i++)
        if (String.Compare(p1[i], p2[i], true) != 0)    // Case insensitive match
            break;

    if (i == 0)     // Cannot make relative path, for example if resides on different drive
        return fromPath;

    String r = String.Join(pathSep, Enumerable.Repeat("..", p2.Length - i).Concat(p1.Skip(i).Take(p1.Length - i)));
    return r;
}

Answer 4

为什么所有这些复杂的解决方案？并涉及到Uri？真的吗？您不必等待第一个例外简洁明了。
不需要任何额外的框架类。

    public static string BuildRelativePath(string absolutePath, string basePath)
    {
        return absolutePath.Substring(basePath.Length);
    }

以防你无法总是添加或总是忽略关闭System.IO.Path.DirectorySeparatorChar到你的字符串，或者你不能混淆参数：

public static string FaultTolerantRelativePath(string absolutePath, string basePath)
{
    if(absolutePath == null || basePath == null)
        return null;

    absolutePath = absolutePath.Replace(System.IO.Path.DirectorySeparatorChar, '/');
    basePath = basePath.Replace(System.IO.Path.DirectorySeparatorChar, '/');

    if (!basePath.EndsWith("/"))
        basePath += "/";

    if (!absolutePath.EndsWith("/"))
        absolutePath += "/";

    if (absolutePath.Length < basePath.Length)
        throw new ArgumentException("absolutePath.Length < basePath.Length ? This can't be. You mixed up absolute and base path.");

    string resultingPath = absolutePath.Substring(basePath.Length);
    resultingPath = resultingPath.Replace('/', System.IO.Path.DirectorySeparatorChar);

    return resultingPath;
}

如何建立相对于特定文件夹的绝对路径？

4 个答案: