To programmatically log in to Weibo (weibo.com) and extract session cookies using Selenium with ChromeDriver in C#, follow the implementation below. This approach assumes no CAPTCHA or two-factor authentication is triggered during login.

using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;

public class WeiboCookieExtractor
{
    private static readonly string Username = "your_username";
    private static readonly string Password = "your_password";

    public static string RetrieveCookies()
    {
        var options = new ChromeOptions();
        // Optional: run headless for background execution
        // options.AddArgument("--headless");

        using var driver = new ChromeDriver(options);
        driver.Navigate().GoToUrl("https://weibo.com");
        
        // Wait for initial page load
        Thread.Sleep(15000);

        // Click the login button
        var loginTrigger = driver.FindElement(By.XPath("//a[@node-type='loginBtn']"));
        loginTrigger.Click();

        Thread.Sleep(10000);

        // Locate username and password fields
        var usernameField = driver.FindElement(By.XPath("//input[@node-type='username' and @tabindex='3']"));
        var passwordFields = driver.FindElements(By.XPath("//input[@name='password']"));
        var passwordField = passwordFields[2]; // Target the correct password input

        // Enter credentials
        usernameField.SendKeys(Username);
        Thread.Sleep(5000);
        passwordField.SendKeys(Password);

        // Submit login form
        var submitButtons = driver.FindElements(By.XPath("//a[@node-type='submitBtn']"));
        var submitButton = submitButtons[2];
        submitButton.Click();

        // Allow time for post-login redirect and cookie setting
        Thread.Sleep(5000);

        // Extract all cookies as a dictionary
        var cookies = driver.Manage().Cookies.AllCookies;
        var cookieDict = new Dictionary<string, string>();
        foreach (var cookie in cookies)
        {
            cookieDict[cookie.Name] = cookie.Value;
        }

        // Format as cookie header string (e.g., "key1=value1; key2=value2")
        var builder = new StringBuilder();
        foreach (var kvp in cookieDict)
        {
            builder.Append($"{kvp.Key}={kvp.Value}; ");
        }

        var cookieString = builder.ToString().TrimEnd(' ', ';');
        return cookieString;
    }
}

Key Considerations:

• Introduce deliberate delays (Thread.Sleep) before interacting with elements or extracting cookies to ensure the DOM and resources have fully loaded.
• This method only works when Weibo does not require solving a CAPTCHA or completing additional verification steps.
• For production use, conisder replacing fixed sleep durations with explicit waits (e.g., WebDriverWait) for better reliability.