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我花了几个小时思考为什么这不起作用

我正在尝试使用 ScrapySharp 来抓取网站，现在只是尝试示例网站然后转移到我的实际网站。

每次我form.Submit()在我的程序中执行一次时，都会遇到 System.AggregateException（指定的演员表无效）

我的代码：

using System;
using System.IO;
using System.Linq;
using System.Net;
using HtmlAgilityPack;
using ScrapySharp.Extensions;
using ScrapySharp.Html;
using ScrapySharp.Html.Forms;
using ScrapySharp.Network;

namespace WebScraper
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            ScrapingBrowser browser = new ScrapingBrowser();

            //set UseDefaultCookiesParser as false if a website returns invalid cookies format
            //browser.UseDefaultCookiesParser = false;
            browser.AllowAutoRedirect = true;
            browser.AllowMetaRedirect = true;
            WebPage homePage = browser.NavigateToPage(new Uri("http://the-internet.herokuapp.com/login"));

            PageWebForm form = homePage.FindForm("login");
            form["username"] = "tomsmith";
            form["password"] = "SuperSecretPassword!";
            form.Method = HttpVerb.Get; //I tried both .Post and .Get
            WebPage resultsPage = form.Submit(); //THIS IS WHERE I GET THE ERROR
            Console.WriteLine(resultsPage);

        }
    }
}

我的错误：

System.AggregateException：发生一个或多个错误。（指定的转换无效。）---> System.InvalidCastException：指定的转换无效。在 ScrapySharp.Network.ScrapingBrowser.CreateRequest (System.Uri url, ScrapySharp.Network.HttpVerb 动词) [0x0000b] in <0a639adc663f45108f057c429262c620>:0 在 ScrapySharp.Network.ScrapingBrowser.NavigateToPageAsync (System.Uri url, ScrapySharp.Network.HttpVerb 动词, System.String data, System.String contentType) [0x00066] in <0a639adc663f45108f057c429262c620>:0 --- 内部异常堆栈跟踪结束 --- 在 System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00011 ] 在 /Users/builder/jenkins/workspace/build-package-osx-mono/2019-06/external/bockbuild/builds/mono-x64/external/corert/src/System.Private。1[TResult].GetResultCore (System.Boolean waitCompletionNotification) [0x0002b] in /Users/builder/jenkins/workspace/build-package-osx-mono/2019-06/external/bockbuild/builds/mono-x64/external/corert/src/System.Private.CoreLib/src/System/Threading/Tasks/Future.cs:496 at System.Threading.Tasks.Task1[TResult].get_Result () [0x00000] 在 /Users/builder/jenkins/workspace/build-package-osx-mono/2019-06/external/bockbuild/builds/mono-x64/external/corert/src/System .Private.CoreLib/src/System/Threading/Tasks/Future.cs:466 在 ScrapySharp.Network.ScrapingBrowser.NavigateToPage （System.Uri url，ScrapySharp.Network.HttpVerb 动词，System.String 数据，System.String contentType）[ 0x0000b] in <0a639adc663f45108f057c429262c620>:0 在 ScrapySharp.Html.Forms.PageWebForm.Submit () [0x00023] in <0a639adc663f45108f057c429262c620>:0 在 WebScraper.MainClass/x [0006] inargsUserClass.Main (0006[] arib/Projects/WebScraper/WebScraper/Program.cs:29

我厌倦了这个错误，非常感谢任何和所有的帮助..谢谢

4

1 回答 1

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问题是当你使用时form["username"]，结果是一个字符串。您想获得FormField，您可以使用以下代码执行此操作：

WebPage homePage = browser.NavigateToPage(new Uri("http://the-internet.herokuapp.com/login"));
PageWebForm form = homePage.FindForm("login");
var formFields = form.FormFields;
foreach (var field in formFields)
{
    if (field.Name.Equals("username", StringComparison.OrdinalIgnoreCase))
    {
        field.Value = "tomsmith";

    }
    else if (field.Name.Equals("password", StringComparison.OrdinalIgnoreCase))
    {
        field.Value = "SuperSecretPassword!";

    }
}

WebPage resultsPage = form.Submit();
Console.WriteLine(resultsPage);

或者，您可以使用Find()获取FormField：

var usernameField = form.FormFields.Find(x => x.Name == "username");
于 2020-07-07T01:09:38.440 回答