在Java selenium中选择下拉列表时找不到元素错误

Question

这是我写的代码 当weblist从下拉列表中选择第二个用户时，我得到以下错误 由于在缓存中找不到元素而导致 - 可能自查找以来页面已更改

代码是

import java.util.List;
import java.util.concurrent.TimeUnit;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.Select;

public class SimpleBrowseroperation 
{

public static void main(String[] args) throws InterruptedException 
{
    WebDriver driver = new FirefoxDriver();
    //WebDriver driver = new InternetExplorerDriver();
    //WebDriver driver = new ChromeDriver();        
    //driver.navigate().to("https://google.co.in");
    driver.navigate().to("https://testnwadmin.aditi.com/nwadmin/spages/home.aspx");
    List<WebElement> ele = driver.findElements(By.xpath("//*[@id='divLoginSection']/div/div[3]"));
    driver.findElement(By.id("Login1_txtEmailID")).sendKeys("testdata5@aditi.com");
    //driver.findElement(By.id("Login1_txtPassword")).sendKeys("Testing1*");
    driver.findElement(By.id("Login1_btnLogin")).click();
    driver.findElement(By.xpath("//*[@id='sliding-navigation']/li[2]/a")).click();
    String ViewMorelink="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[3]/td";
    String ClkViewMore="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[3]//a[contains(text(),'View')]";
    String Covered="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[2]/td/table/tbody/tr[%s]/td[2]";
    String ViewDetails="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[2]/td/table/tbody/tr[%s]/td[3]/a";
    String TableRowCount="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[2]/td/table/tbody/tr";
    String ViewCarrier="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[2]/td/table/tbody/tr[%s]/td[3]";
    String ClaimPayer="//*[@id='divContentHolder']/div[2]/table[%s]/tbody/tr[2]/td/table/tbody/tr[%s]/td[4]";

    Select WebList=new Select(driver.findElement(By.xpath("//*[@id='ddlSelectUser']")));
    List<WebElement> userlist = WebList.getOptions();
    int usercnt=userlist.size();
    System.out.println(usercnt);
    String[] linkTexts = new String[usercnt];
    int i = 0;
    for (WebElement e : userlist) 
    {
    linkTexts[i] = e.getText();
    i++;
    }
    for(int usrcnt=0;usrcnt<=usercnt;usrcnt++)
    {

        WebList.selectByIndex(usrcnt);
        > /
                    > somecode
                    > /

    }

}
}