如何解析 ASP.NET“~”没有控件的情况下应用程序到网站根目录的路径？

Question

我想从非页面上下文（例如 Global.asax (HttpApplication)、HttpModule、HttpHandler 等）内部解析“~/whatever”，但只能找到特定于控件（和页面）的此类解析方法。

我认为应用程序应该有足够的知识来能够在页面上下文之外映射它。不？或者至少对我来说是有意义的，在其他情况下，只要知道应用程序根，它就应该可以解决。

更新：原因是我在 web.configuration 文件中粘贴了“~”路径，并希望从上述非控制场景中解决它们。

更新 2： 我试图将它们解析为网站根目录，例如 Control.Resolve(..) URL 行为，而不是文件系统路径。

Answer 1

答案如下：
ASP.Net：使用系统共享/静态函数中的.Web.UI.Control.ResolveUrl()

string absoluteUrl = VirtualPathUtility.ToAbsolute("~/SomePage.aspx");

Answer 2

您可以通过直接访问 HttpContext.Current 对象来做到这一点：

var resolved = HttpContext.Current.Server.MapPath("~/whatever")

需要注意的一点是，HttpContext.Current 只会是非 null code> 在实际请求的上下文中。例如，它在 Application_Stop 事件中不可用。

Answer 3

在 Global.asax 中添加以下内容：

private static string ServerPath { get; set; }

protected void Application_BeginRequest(Object sender, EventArgs e)
{
    ServerPath = BaseSiteUrl;
}

protected static string BaseSiteUrl
{
    get
    {
        var context = HttpContext.Current;
        if (context.Request.ApplicationPath != null)
        {
            var baseUrl = context.Request.Url.Scheme + "://" + context.Request.Url.Authority + context.Request.ApplicationPath.TrimEnd('/') + '/';
            return baseUrl;
        }
        return string.Empty;
    }
}

Answer 4

我还没有调试这个傻瓜，但我把它作为手动解决方案扔在那里，因为在 Control 之外的 .NET Framework 中找不到 Resolve 方法。

这对我来说确实适用于“~/whatever”。

/// <summary>
/// Try to resolve a web path to the current website, including the special "~/" app path.
/// This method be used outside the context of a Control (aka Page).
/// </summary>
/// <param name="strWebpath">The path to try to resolve.</param>
/// <param name="strResultUrl">The stringified resolved url (upon success).</param>
/// <returns>true if resolution was successful in which case the out param contains a valid url, otherwise false</returns>
/// <remarks>
/// If a valid URL is given the same will be returned as a successful resolution.
/// </remarks>
/// 
static public bool TryResolveUrl(string strWebpath, out string strResultUrl) {

    Uri uriMade = null;
    Uri baseRequestUri = new Uri(HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority));

    // Resolve "~" to app root;
    // and create http://currentRequest.com/webroot/formerlyTildeStuff
    if (strWebpath.StartsWith("~")) {
        string strWebrootRelativePath = string.Format("{0}{1}", 
            HttpContext.Current.Request.ApplicationPath, 
            strWebpath.Substring(1));

        if (Uri.TryCreate(baseRequestUri, strWebrootRelativePath, out uriMade)) {
            strResultUrl = uriMade.ToString();
            return true;
        }
    }

    // or, maybe turn given "/stuff" into http://currentRequest.com/stuff
    if (Uri.TryCreate(baseRequestUri, strWebpath, out uriMade)) {
        strResultUrl = uriMade.ToString();
        return true;
    }

    // or, maybe leave given valid "http://something.com/whatever" as itself
    if (Uri.TryCreate(strWebpath, UriKind.RelativeOrAbsolute, out uriMade)) {
        strResultUrl = uriMade.ToString();
        return true;
    }

    // otherwise, fail elegantly by returning given path unaltered.    
    strResultUrl = strWebpath;
    return false;
}

Answer 5

public static string ResolveUrl(string url)
{
    if (string.IsNullOrEmpty(url))
    {
        throw new ArgumentException("url", "url can not be null or empty");
    }
    if (url[0] != '~')
    {
        return url;
    }
    string applicationPath = HttpContext.Current.Request.ApplicationPath;
    if (url.Length == 1)
    {
        return applicationPath;
    }
    int startIndex = 1;
    string str2 = (applicationPath.Length > 1) ? "/" : string.Empty;
    if ((url[1] == '/') || (url[1] == '\\'))
    {
        startIndex = 2;
    }
    return (applicationPath + str2 + url.Substring(startIndex));
}

Answer 6

不要使用 MapPath，而是尝试使用 System.AppDomain.BaseDirectory。对于网站来说，这应该是您网站的根目录。然后执行 System.IO.Path.Combine 与您要传递给 MapPath 的任何内容（不带“~”）。