How to use clipboard to copy data from Excel Sheet to DataTable?

Question

I have a Winform project, created on Microsoft Framework 3.5. The users may have installed Windows 7 or Windows XP, and Office 2007 or above.

I'm working on in a procedure to get the clipboard data and put in on a C# DataTable. I already created a method to get the raw data from the clipboard and upload it in a DataTable.

But in some cases, the Excel data shows a value, but internally have another:

I'm investigating a method to get the raw data from Excel:

string XmlFmt = "XML Spreadsheet";
var clipboard = Clipboard.GetDataObject();

if (clipboard.GetDataPresent(XmlFmt))
{
    var clipData = clipboard.GetData(XmlFmt);
    StreamReader streamReader = new StreamReader((MemoryStream)clipData);
    streamReader.BaseStream.SetLength(streamReader.BaseStream.Length - 1);

    string xmlText = streamReader.ReadToEnd();
    var stream = new StringReader(xmlText);

    XmlDocument xmlDocument = new XmlDocument();
    xmlDocument.LoadXml(xmlText);

    DataSet dsExcelData = new DataSet();
    dsExcelData.ReadXml(new XmlNodeReader(xmlDocument));
}

But, this method retrieves me a DataSet with multiples tables with the configuration of each part of the Excel Data:

Basically, I want to convert these structures to a simple DataTable with only the raw data. Someone could help me with a hint how achieve this? ...I don't want to use a third party library in this implementation.

Answer 1

I found a clean and bullet-proof solution. Here the code:

First, a extension to convert a XmlDocument to XElement:

/// <summary> Convert XML Document to XDocument </summary>
/// <param name="xmlDocument">Attached XML Document</param>
public static XDocument fwToXDocument(this XmlDocument xmlDocument)
{
    using (XmlNodeReader xmlNodeReader = new XmlNodeReader(xmlDocument))
    {
        xmlNodeReader.MoveToContent();
        return XDocument.Load(xmlNodeReader);
    }
}

The complete function:

private DataTable clipboardExcelToDataTable(bool blnFirstRowHasHeader = false)
{
    string strTime = "S " + DateTime.Now.ToString("mm:ss:fff");
    var clipboard = Clipboard.GetDataObject();
    if (!clipboard.GetDataPresent("XML Spreadsheet")) return null;

    strTime += "\r\nRead " + DateTime.Now.ToString("mm:ss:fff");
    StreamReader streamReader = new StreamReader((MemoryStream)clipboard.GetData("XML Spreadsheet"));
    strTime += "\r\nFinish read " + DateTime.Now.ToString("mm:ss:fff");
    streamReader.BaseStream.SetLength(streamReader.BaseStream.Length - 1);

    XmlDocument xmlDocument = new XmlDocument();
    xmlDocument.LoadXml(streamReader.ReadToEnd());
    strTime += "\r\nRead XML Document " + DateTime.Now.ToString("mm:ss:fff");

    XNamespace ssNs = "urn:schemas-microsoft-com:office:spreadsheet";
    DataTable dtData = new DataTable();

    var linqRows = xmlDocument.fwToXDocument().Descendants(ssNs + "Row").ToList<XElement>();

    for (int x = 0; x < linqRows.Max(a => a.Descendants(ssNs + "Cell").Count()); x++)
        dtData.Columns.Add("Column " + (x + 1).ToString());

    int intCol = 0;

    DataRow drCurrent;

    linqRows.ForEach(rowElement =>
        {
            intCol = 0;
            drCurrent = dtData.Rows.Add();
            rowElement.Descendants(ssNs + "Cell")
                .ToList<XElement>()
                .ForEach(cell => drCurrent[intCol++] = cell.Value);
        });

    if (blnFirstRowHasHeader)
    {
        int x = 0;
        foreach (DataColumn dcCurrent in dtData.Columns)
            dcCurrent.ColumnName = dtData.Rows[0][x++].ToString();

        dtData.Rows.RemoveAt(0);
    }

    strTime += "\r\nF " + DateTime.Now.ToString("mm:ss:fff");

    return dtData;
}

The process takes ~15 seconds to read ~25,000 rows.

Works perfectly for any kind of data. Basically, the method creates a grid with the same structure of the Excel WorkSheet. Merge of rows or columns will fill up the first cell able. All columns will be string DataType by default.