Loop thorough multiple HTML tables in HTML Agility Pack

c# html html-agility-pack xpath

Question

I followed the example in the below link and was able to parse HTML table successfully to a datatable.

http://blog.ditran.net/parsing-html-table-to-c-usable-datalist/

But I am not able to parse multiple tables,When I traverse through TR the first TR always have the column names and the rest have the data in each table.So I am using this logic and storing the table data in dictionary and sending to my ToDataTable function.

Can someone help on how can I loop thoriugh multiple tables and implement the same logic.Appreciate it.

var tRowList = doc.DocumentNode.SelectNodes("//tr");
foreach (HtmlNode tRow in tRowList)
                    {
                        if (previousRowSpanList.Count > 0)
                        {
                            theDict = previousRowSpanList[0];
                            previousRowSpanList.Remove(theDict);        //remove it off the list
                            isWorkingWithRowSpan = true;
                        }
                        else
                        {
                            theDict = new List<KeyValuePair<string, string>>();
                            isWorkingWithRowSpan = false;
                        }
                        var tCellList = tRow.SelectNodes("td|th");
                        tCelCount = tCellList.Count;
                        if (tCelCount > 0 &&
                        !(tCelCount == 1 && string.IsNullOrEmpty(tCellList[0].InnerText.Trim()))
                        )
                        {
                            //colOrder = 1;
                            IsNullEntireRow = true;
                            for (int colIndex = 0; colIndex < tCelCount; colIndex++)
                            {
                                cell = tCellList[colIndex];
                                ColInnerText = cell.InnerText.Replace("&nbsp;", " ").Trim();
                                if (!string.IsNullOrEmpty(ColInnerText))
                                    IsNullEntireRow = false;

//

 static DataTable ToDataTable(List<List<KeyValuePair<string, string>>> list)
        {
            DataTable result = new DataTable();
            if (list.Count == 0)
                return result;

            result.Columns.AddRange(
        list.First().Select(r => new DataColumn(r.Value)).ToArray()
    );



            list= list.Skip(1).ToArray().ToList();
            list.ForEach(r => result.Rows.Add(r.Select(c => c.Value).Cast<object>().ToArray()));


            return result;

sample HTML:

<table>
<tbody>
<tr><td style="background-color:#A9F5A9;font-weight:bold;" class="center">Node</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">Logtime</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">Hardware</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">Prcstate A</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">Prcstate B</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">Cluster</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">RAID</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">AD replication A</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">AD replication B</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">File replication A</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">File replication B</td><td style="background-color:#A9F5A9;font-weight:bold;" class="center">hcstart RESULT</td></tr>
<tr><td class="center">DTMSCB1</td><td class="center">2016-08-26 16:40</td><td class="center">APG43L</td><td class="center">active</td><td class="center">passive</td><td class="center">-</td><td class="center">-</td><td class="center">-</td><td class="center">-</td><td class="center">-</td><td class="center">-</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">Not OK</td></tr>
<tr><td class="center">MSC9</td><td class="center">2016-08-26 16:40</td><td class="center">APG40C/4</td><td class="center">passive</td><td class="center">active</td><td class="center">OK</td><td class="center">OK</td><td class="center">OK</td><td class="center">OK</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">Not OK</td><td class="center">OK</td><td class="center">-</td></tr>
</tbody>
</table>


<table>
<tbody>
<tr><td style="background-color:#A9F5A9;" class="center">Node Type</td><td style="background-color:#A9F5A9;" class="center">Node</td><td style="background-color:#A9F5A9;" class="center">Log Time</td><td style="background-color:#A9F5A9;" class="center">New Mon. Alarms</td><td style="background-color:#A9F5A9;" class="center">Mon. Alarms Total</td><td style="background-color:#A9F5A9;" class="center">Other Alarms</td><td style="background-color:#A9F5A9;" class="center">MML</td></tr>
<tr><td class="center">BSC</td><td class="center">BMBSC1</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">46</td><td class="center">445</td><td class="center">OK</td></tr>
<tr><td class="center">BSC</td><td class="center">BMBSC2C</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">27</td><td class="center">609</td><td class="center">OK</td></tr>
<tr><td class="center">BSC</td><td class="center">CYBSC1</td><td class="center">2016-08-26 16:45</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">1</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">45</td><td class="center">665</td><td class="center">OK</td></tr>
<tr><td class="center">BSC</td><td class="center">CYBSC2C</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">30</td><td class="center">849</td><td class="center">OK</td></tr>
<tr><td class="center">MSC-BC</td><td class="center">CYMSCB1</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">38</td><td class="center">283</td><td class="center">OK</td></tr>
<tr><td class="center">BSC</td><td class="center">DTBSC1</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">48</td><td class="center">201</td><td class="center">OK</td></tr>
<tr><td class="center">BSC</td><td class="center">DTBSC2</td><td class="center">2016-08-26 16:45</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">1</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">31</td><td class="center">310</td><td class="center">OK</td></tr>
<tr><td class="center">MSC-BC</td><td class="center">DTMSCB1</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">25</td><td class="center">130</td><td class="center">OK</td></tr>
<tr><td class="center">HLR</td><td class="center">HLR1</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">16</td><td class="center">12</td><td class="center">OK</td></tr>
<tr><td class="center">HLR</td><td class="center">HLR2</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">24</td><td class="center">10</td><td class="center">OK</td></tr>
<tr><td class="center">MSC-S</td><td class="center">MSC10</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">48</td><td class="center">79</td><td class="center">OK</td></tr>
<tr><td class="center">MSC-S</td><td class="center">MSC9</td><td class="center">2016-08-26 16:45</td><td class="center">0</td><td style="background-color:#FF0000;color:#FFFFFF;font-weight:bold;" class="center">46</td><td class="center">131</td><td class="center">OK</td></tr>
</tbody>
</table>

Accepted Answer

I'll keep the first answer for reference, but below is a method that will split the original html into a string array with each string element containing the HTML for one table:

public static string[] ParseHtmlSplitTables(string htmlString)
{
    string[] result = new string[] { };

    if (!String.IsNullOrWhiteSpace(htmlString))
    {
        HtmlDocument doc = new HtmlDocument();
        doc.LoadHtml(htmlString);

        var tableNodes = doc.DocumentNode.SelectNodes("//table");
        if (tableNodes != null)
        {
            result = Array.ConvertAll<HtmlNode, string>(tableNodes.ToArray(), n => n.OuterHtml);
        }
    }

    return result;
}

With the result you can then proceed to parse each table:

string[] htmlTables = ParseHtmlSplitTables(htmlString);

foreach (string html in htmlTables)
{
    List<List<KeyValuePair<string, string>>> parseResult = ParseHtmlToDataTable(html);

    DataTable dataTable = ToDataTable(parseResult);
}

Popular Answer

Since you want to parse multiple html tables you should return a DataSet that will have one DataTable per html table. If table headers are present, the code below will add column names to the corresponding DataTable. The html table id will be used as the name for the DataTable with which you can use to directly access from the DataSet:

Method to convert html tables to a DataSet:

public static DataSet HtmlTablesToDataset(string html)
{
    var resultDataset = new DataSet();

    HtmlDocument doc = new HtmlDocument();
    doc.LoadHtml(html);
    foreach (HtmlNode table in doc.DocumentNode.SelectNodes("//table"))
    {
        var resultTable = new DataTable(table.Id);

        foreach (HtmlNode row in table.SelectNodes("tr"))
        {
            var headerCells = row.SelectNodes("th");
            if (headerCells != null)
            {
                foreach (HtmlNode cell in headerCells)
                {
                    resultTable.Columns.Add(cell.InnerText);
                }
            }

            var dataCells = row.SelectNodes("td");
            if (dataCells != null)
            {
                var dataRow = resultTable.NewRow();
                for (int i=0; i < dataCells.Count; i++)
                {
                    dataRow[i] = dataCells[i].InnerText;
                }

                resultTable.Rows.Add(dataRow);
            }
        }

        resultDataset.Tables.Add(resultTable);
    }

    return resultDataset;
}

Test code:

var resultDS = HtmlTablesToDataset(html);

foreach(DataTable dt in resultDS.Tables)
{
    Console.WriteLine("Table: " + dt.TableName);

    string line = "";

    foreach (DataColumn col in dt.Columns)
    {
        line += col.ToString() + " ";
    }
    Console.WriteLine(line.Trim());

    foreach (DataRow row in dt.Rows)
    {
        line = "";
        foreach (DataColumn col in dt.Columns)
        {
            line += row[col].ToString() + " ";
        }

        Console.WriteLine(line.Trim());
    }
}

Sample HTML:

string html =
@"
<html>
    <head>
        <title>Test</title>
    </head>
    <body>
        <table id='t1'>
            <tr>
                <th>Col1</th>
                <th>Col2</th>
            </tr>
            <tr>
                <td>1</td>
                <td>2</td>
            </tr>
            <tr>
                <td>3</td>
                <td>4</td>
            </tr>
        </table>
        <table id='t2'>
            <tr>
                <th>Col1</th>
                <th>Col2</th>
            </tr>
            <tr>
                <td>5</td>
                <td>6</td>
            </tr>
            <tr>
                <td>7</td>
                <td>8</td>
            </tr>        
        </table>
    </body>
</html>                
";



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Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow
Is this KB legal? Yes, learn why