到目前为止，我有以下代码：
Dim wreqBalQtr As HttpWebRequest = WebRequest.Create("http://www.reuters.com/finance/stocks/incomeStatement/detail?stmtType=BAL&perType=INT&symbol=" & tickerValue)
wreqBalQtr.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5"
wreqBalQtr.Method = "get"
Dim proxBalQtr As IWebProxy = wreqBalQtr.Proxy
proxBalQtr.Credentials = CredentialCache.DefaultCredentials
Dim documentBalQtr As New HtmlAgilityPack.HtmlDocument
Dim webBalQtr As New HtmlAgilityPack.HtmlWeb
webBalQtr.UseCookies = True
webBalQtr.PreRequest = New HtmlAgilityPack.HtmlWeb.PreRequestHandler(AddressOf onPreReq)
wreqBalQtr.CookieContainer = cookies
Dim resBalQtr As HttpWebResponse = wreqBalQtr.GetResponse()
documentBalQtr.Load(resBalQtr.GetResponseStream, True)
Dim TotalCurrentAssets = documentBalQtr.DocumentNode.SelectSingleNode("//table[@class='dataTable Financials']//tr[13]//td[3]")
HTML是：
<table class="dataTable financials" cellspacing="1" cellpadding="0" width="100%">
<tr>
<th class="rh">
<span class="units">
In Millions of U.S. Dollars<br/>
(except for per share items)<br/>
</span>
</th>
<th class="data">
2012<br/>
2012-09-30<br/>
<span class="period">
</span>
</th>
<th class="data">
2012<br/>
2012-06-30<br/>
<span class="period">
</span>
</th>
<th class="data">
2012<br/>
2012-03-31<br/>
<span class="period">
</span>
</th>
<th class="data">
2011<br/>
2011-12-31<br/>
<span class="period">
Reclassified<br/>
2012-06-30<br/>
</span>
</th>
<th class="data">
2011<br/>
2011-09-30<br/>
<span class="period">
</span>
</th>
</tr>
<tr class="both stripe ">
<td class="rh">Cash</td>
<td class="data plus">6,224.0</td>
<td class="data plus">7,463.0</td>
<td class="data plus">11,239.0</td>
<td class="data plus">4,712.0</td>
<td class="data plus">4,209.0</td>
</tr>
<tr class="both ">
<td class="rh">Cash & Equivalents</td>
<td class="data plus">10,036.0</td>
<td class="data plus">7,974.0</td>
<td class="data plus">11,869.0</td>
<td class="data plus">5,271.0</td>
<td class="data plus">6,421.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Short Term Investments</td>
<td class="data plus">29,464.0</td>
<td class="data plus">27,685.0</td>
<td class="data plus">26,208.0</td>
<td class="data plus">34,643.0</td>
<td class="data plus">31,930.0</td>
</tr>
<tr class="both ">
<td class="rh">Cash and Short Term Investments</td>
<td class="data plus">45,724.0</td>
<td class="data plus">43,122.0</td>
<td class="data plus">49,316.0</td>
<td class="data plus">44,626.0</td>
<td class="data plus">42,560.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Accounts Receivable - Trade, Net</td>
<td class="data plus">7,259.0</td>
<td class="data plus">6,866.0</td>
<td class="data plus">5,163.0</td>
<td class="data plus">5,427.0</td>
<td class="data plus">4,583.0</td>
</tr>
<tr class="both ">
<td class="rh">Notes Receivable - Short Term</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both stripe ">
<td class="rh">Receivables - Other</td>
<td class="data plus">550.0</td>
<td class="data plus">475.0</td>
<td class="data plus">550.0</td>
<td class="data plus">745.0</td>
<td class="data plus">1,278.0</td>
</tr>
<tr class="both ">
<td class="rh">Total Receivables, Net</td>
<td class="data plus">7,809.0</td>
<td class="data plus">7,341.0</td>
<td class="data plus">5,713.0</td>
<td class="data plus">6,172.0</td>
<td class="data plus">5,861.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Total Inventory</td>
<td class="data plus">618.0</td>
<td class="data plus">634.0</td>
<td class="data plus">--</td>
<td class="data plus">35.0</td>
<td class="data plus">--</td>
</tr>
<tr class="both ">
<td class="rh">Prepaid Expenses</td>
<td class="data plus">2,440.0</td>
<td class="data plus">2,614.0</td>
<td class="data plus">1,779.0</td>
<td class="data plus">1,710.0</td>
<td class="data plus">1,406.0</td>
</tr>
<tr class="sum stripe ">
<td class="rh">Other Current Assets, Total</td>
<td class="data plus">230.0</td>
<td class="data plus">146.0</td>
<td class="data plus">51.0</td>
<td class="data plus">215.0</td>
<td class="data plus">215.0</td>
</tr>
<tr class="both total">
<td class="rh">Total Current Assets</td>
<td class="data plus">56,821.0</td>
<td class="data plus">53,857.0</td>
<td class="data plus">56,859.0</td>
<td class="data plus">52,758.0</td>
<td class="data plus">50,042.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Property/Plant/Equipment, Total - Gross</td>
<td class="data plus">17,038.0</td>
<td class="data plus">16,137.0</td>
<td class="data plus">14,963.0</td>
<td class="data plus">14,400.0</td>
<td class="data plus">13,815.0</td>
</tr>
<tr class="both ">
<td class="rh">Accumulated Depreciation, Total</td>
<td class="data minus">(5,637.0)</td>
<td class="data minus">(5,228.0)</td>
<td class="data minus">(5,088.0)</td>
<td class="data minus">(4,797.0)</td>
<td class="data minus">(4,611.0)</td>
</tr>
<tr class="both stripe ">
<td class="rh">Property/Plant/Equipment, Total - Net</td>
<td class="data plus">11,401.0</td>
<td class="data plus">10,909.0</td>
<td class="data plus">9,875.0</td>
<td class="data plus">9,603.0</td>
<td class="data plus">9,204.0</td>
</tr>
<tr class="both ">
<td class="rh">Goodwill, Net</td>
<td class="data plus">10,485.0</td>
<td class="data plus">10,120.0</td>
<td class="data plus">7,325.0</td>
<td class="data plus">7,346.0</td>
<td class="data plus">6,989.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Intangibles, Net</td>
<td class="data plus">7,754.0</td>
<td class="data plus">7,862.0</td>
<td class="data plus">1,541.0</td>
<td class="data plus">1,578.0</td>
<td class="data plus">1,474.0</td>
</tr>
<tr class="sum ">
<td class="rh">Long Term Investments</td>
<td class="data plus">1,063.0</td>
<td class="data plus">1,040.0</td>
<td class="data plus">880.0</td>
<td class="data plus">790.0</td>
<td class="data plus">891.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Note Receivable - Long Term</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="sum ">
<td class="rh">Other Long Term Assets, Total</td>
<td class="data plus">2,206.0</td>
<td class="data plus">2,263.0</td>
<td class="data plus">664.0</td>
<td class="data plus">499.0</td>
<td class="data plus">488.0</td>
</tr>
<tr class="sum stripe ">
<td class="rh">Other Assets, Total</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both total">
<td class="rh">Total Assets</td>
<td class="data plus">89,730.0</td>
<td class="data plus">86,051.0</td>
<td class="data plus">77,144.0</td>
<td class="data plus">72,574.0</td>
<td class="data plus">69,088.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Accounts Payable</td>
<td class="data plus">2,233.0</td>
<td class="data plus">2,419.0</td>
<td class="data plus">760.0</td>
<td class="data plus">588.0</td>
<td class="data plus">563.0</td>
</tr>
<tr class="both ">
<td class="rh">Payable/Accrued</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both stripe ">
<td class="rh">Accrued Expenses</td>
<td class="data plus">6,347.0</td>
<td class="data plus">5,551.0</td>
<td class="data plus">3,429.0</td>
<td class="data plus">4,356.0</td>
<td class="data plus">3,563.0</td>
</tr>
<tr class="both ">
<td class="rh">Notes Payable/Short Term Debt</td>
<td class="data plus">3,218.0</td>
<td class="data plus">3,218.0</td>
<td class="data plus">2,468.0</td>
<td class="data plus">1,218.0</td>
<td class="data plus">1,218.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Current Port. of LT Debt/Capital Leases</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="sum ">
<td class="rh">Other Current liabilities, Total</td>
<td class="data plus">2,636.0</td>
<td class="data plus">2,840.0</td>
<td class="data plus">3,085.0</td>
<td class="data plus">2,751.0</td>
<td class="data plus">3,544.0</td>
</tr>
<tr class="both stripe total">
<td class="rh">Total Current Liabilities</td>
<td class="data plus">14,434.0</td>
<td class="data plus">14,028.0</td>
<td class="data plus">9,742.0</td>
<td class="data plus">8,913.0</td>
<td class="data plus">8,888.0</td>
</tr>
<tr class="both ">
<td class="rh">Long Term Debt</td>
<td class="data plus">2,988.0</td>
<td class="data plus">2,987.0</td>
<td class="data plus">2,987.0</td>
<td class="data plus">2,986.0</td>
<td class="data plus">2,986.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Capital Lease Obligations</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both ">
<td class="rh">Total Long Term Debt</td>
<td class="data plus">2,988.0</td>
<td class="data plus">2,987.0</td>
<td class="data plus">2,987.0</td>
<td class="data plus">2,986.0</td>
<td class="data plus">2,986.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Total Debt</td>
<td class="data plus">6,206.0</td>
<td class="data plus">6,205.0</td>
<td class="data plus">5,455.0</td>
<td class="data plus">4,204.0</td>
<td class="data plus">4,204.0</td>
</tr>
<tr class="sum ">
<td class="rh">Deferred Income Tax</td>
<td class="data plus">1,461.0</td>
<td class="data plus">1,509.0</td>
<td class="data plus">384.0</td>
<td class="data plus">287.0</td>
<td class="data plus">263.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Minority Interest</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="sum ">
<td class="rh">Other Liabilities, Total</td>
<td class="data plus">2,819.0</td>
<td class="data plus">2,806.0</td>
<td class="data plus">2,319.0</td>
<td class="data plus">2,243.0</td>
<td class="data plus">2,121.0</td>
</tr>
<tr class="both stripe total">
<td class="rh">Total Liabilities</td>
<td class="data plus">21,702.0</td>
<td class="data plus">21,330.0</td>
<td class="data plus">15,432.0</td>
<td class="data plus">14,429.0</td>
<td class="data plus">14,258.0</td>
</tr>
<tr class="sum ">
<td class="rh">Redeemable Preferred Stock, Total</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="sum stripe ">
<td class="rh">Preferred Stock - Non Redeemable, Net</td>
<td class="data plus">0.0</td>
<td class="data plus">0.0</td>
<td class="data plus">0.0</td>
<td class="data plus">0.0</td>
<td class="data plus">0.0</td>
</tr>
<tr class="sum ">
<td class="rh">Common Stock, Total</td>
<td class="data plus">22,204.0</td>
<td class="data plus">21,357.0</td>
<td class="data plus">20,795.0</td>
<td class="data plus">20,264.0</td>
<td class="data plus">19,697.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Additional Paid-In Capital</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both ">
<td class="rh">Retained Earnings (Accumulated Deficit)</td>
<td class="data plus">45,456.0</td>
<td class="data plus">43,280.0</td>
<td class="data plus">40,495.0</td>
<td class="data plus">37,605.0</td>
<td class="data plus">34,901.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Treasury Stock - Common</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both ">
<td class="rh">ESOP Debt Guarantee</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both stripe ">
<td class="rh">Unrealized Gain (Loss)</td>
<td class="data plus">566.0</td>
<td class="data plus">389.0</td>
<td class="data plus">416.0</td>
<td class="data plus">327.0</td>
<td class="data plus">99.0</td>
</tr>
<tr class="sum ">
<td class="rh">Other Equity, Total</td>
<td class="data minus">(198.0)</td>
<td class="data minus">(305.0)</td>
<td class="data plus">6.0</td>
<td class="data minus">(51.0)</td>
<td class="data plus">133.0</td>
</tr>
<tr class="both stripe total">
<td class="rh">Total Equity</td>
<td class="data plus">68,028.0</td>
<td class="data plus">64,721.0</td>
<td class="data plus">61,712.0</td>
<td class="data plus">58,145.0</td>
<td class="data plus">54,830.0</td>
</tr>
<tr class="both total">
<td class="rh">Total Liabilities & Shareholders' Equity</td>
<td class="data plus">89,730.0</td>
<td class="data plus">86,051.0</td>
<td class="data plus">77,144.0</td>
<td class="data plus">72,574.0</td>
<td class="data plus">69,088.0</td>
</tr>
<tr class="both stripe ">
<td class="rh">Shares Outs - Common Stock Primary Issue</td>
<td class="data plus">264.52</td>
<td class="data plus">261.58</td>
<td class="data plus">259.50</td>
<td class="data plus">257.55</td>
<td class="data plus">255.70</td>
</tr>
<tr class="both ">
<td class="rh">Shares Outstanding - Common Issue 2</td>
<td class="data plus">64.04</td>
<td class="data plus">65.36</td>
<td class="data plus">66.40</td>
<td class="data plus">67.34</td>
<td class="data plus">68.05</td>
</tr>
<tr class="both stripe ">
<td class="rh">Shares Outstanding - Common Issue 3</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both ">
<td class="rh">Shares Outstanding - Common Issue 4</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
<tr class="both stripe total">
<td class="rh">Total Common Shares Outstanding</td>
<td class="data plus">328.55</td>
<td class="data plus">326.94</td>
<td class="data plus">325.91</td>
<td class="data plus">324.89</td>
<td class="data plus">323.76</td>
</tr>
<tr class="both total">
<td class="rh">Total Preferred Shares Outstanding</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
<td class="data plus">--</td>
</tr>
</table>
</div>
</div>
</div>
当我尝试使用变量 TotalCurrentAssets 从 Total Current Assets 行中提取第二列时（数字应为 53,857.0）。我得到“用户代码未处理 NullReferenceException。对象引用未设置为对象实例。”
这是否意味着变量 TotalCurrentAssets 什么也不返回？我假设我的错误出现在我的最后一行代码中。
附加信息
我不知道这是否会影响我的问题，但我在原始帖子中的代码之前运行此代码：
Dim wreqBeta As HttpWebRequest = WebRequest.Create("http://www.reuters.com/finance/stocks/overview?symbol=" & tickerValue)
wreqBeta.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5"
wreqBeta.Method = "get"
Dim proxBeta As IWebProxy = wreqBeta.Proxy
proxBeta.Credentials = CredentialCache.DefaultCredentials
Dim documentBeta As New HtmlAgilityPack.HtmlDocument
Dim webBeta As New HtmlAgilityPack.HtmlWeb
webBeta.UseCookies = True
webBeta.PreRequest = New HtmlAgilityPack.HtmlWeb.PreRequestHandler(AddressOf onPreReq)
wreqBeta.CookieContainer = cookies
Dim resBeta As HttpWebResponse = wreqBeta.GetResponse()
documentBeta.Load(resBeta.GetResponseStream, True)
Dim beta = documentBeta.DocumentNode.SelectSingleNode("//div[@id='overallRatios']//table[@class='dataTable']//tr[1]//td[2]")
在开始解析新网页之前，我是否需要关闭此代码中的任何内容？