Question

My project idea is to create filters so that I can filter out what I want the data in XML files to be appeared. I am facing the issue with datetime inconsistency. My filters are currently using TextBoxes. I was hoping to use the DateTimePicker but I have no idea how can I use it. This is my first attempt in programming and C#. Basically as long as part of the data in <item></item> tag meets the criteria (ie filters), then the whole <item></item> will be shown in my RichTextBox result area. Currently I am stuck at this point where I need to deal with the datetime format. I am totally lost.

My partial XML File:

<item>
  <title>[alfista] Max</title>
  <author>alfista</author>
  <description>Or was it just populated by non spread betters, so you found it dull and boring??  See where I am coming from?  Puffy just posted general views about direction, and I much prefer them, but then I would wouldnt I.</description>
  <link>http://www.lse.co.uk/shareChat.asp?ShareTicker=BARC&amp;post=5657481</link>
  <pubDate>Tue, 08 Aug 2012 16:08:32 GMT</pubDate>
</item>
<item>
  <title>[Maximillian] F430</title>
  <author>Maximillian</author>
  <description>Ignore the snide comments and please  keep posting in the style you have been. This board was virtually dead until you came along a few weeks ago.  </description>
  <link>http://www.lse.co.uk/shareChat.asp?ShareTicker=BARC&amp;post=5657462</link>
  <pubDate>Tue, 07 Aug 2012 16:05:04 GMT</pubDate>
</item>
<item>
  <title>[colti] divi</title>
  <author>colti</author>
  <description>Does anyone know when the divi is actually paid please</description>
  <link>http://www.lse.co.uk/shareChat.asp?ShareTicker=BARC&amp;post=5658759</link>
  <pubDate>Wed, 06 Aug 2012 06:46:25 GMT</pubDate>
</item>
<item>
  <title>[SamSri] alfista</title>
  <author>SamSri</author>
  <description>Well, sea of knowledge is out there and thus there is always something new to learn. It's better for me to be humble.</description>
  <link>http://www.lse.co.uk/shareChat.asp?ShareTicker=BARC&amp;post=5659714</link>
  <pubDate>Wed, 05 Aug 2012 08:52:35 GMT</pubDate>
</item>

My function:

private void searchComByStartDate()
{
    // Process the list of files found in the directory. 
    string[] fileEntries = Directory.GetFiles(sourceDir);
    foreach (string fileName in fileEntries)
    {
        XmlDocument xmlDoc = new XmlDocument(); //* create an xml document object.

        string docPath = fileName;

        xmlDoc.Load(docPath); //* load the XML document from the specified file.

        XmlNodeList nodeList = xmlDoc.GetElementsByTagName("item");

        foreach (XmlNode node in nodeList)
        {

            XmlElement itemElement = (XmlElement)node;

            string itemDate = itemElement.GetElementsByTagName("pubDate")[0].InnerText;

            if (itemDate >= txtComStartDate)
            {
                string itemAuthor = itemElement.GetElementsByTagName("author")[0].InnerText;
                string itemTitle = itemElement.GetElementsByTagName("title")[0].InnerText;
                string itemDescription = itemElement.GetElementsByTagName("description")[0].InnerText;

                richComResults.AppendText("Author: " + itemAuthor + "\nDate: " + itemDate + "\nTitle: " + itemTitle + "\nDescription: " + itemDescription + "\n\n--------\n\n");
            }
        }
    }
}

In this line if (itemDate >= txtComStartDate), it is obviously very wrong because it says “Operator >= cannot be applied to string and textbox”. I know LINQ to XML can make my life easier, but if I want to stick with XmlDocument, can somebody please fix my current problem? Because I am very new to programming, I just learnt very little thing about parsing XML files.

I have two filters in my C# winforms which are txtComStartDate and txtComEndDate. Users can either input txtComStartDate or txtComEndDate or both.

Case 1: if txtComStartDate – 06/08/12, then the result will show in my richComResults only the <item></item> that start from 06/08/12 to the latest.

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Case 2: if txtComEndDate – 07/08/12, then the result will show in my richComResults only the <item></item> that appear before 07/08/12.

---

Case 3: if txtComStartDate – 06/08/12 & txtComEndDate – 07/08/12, then the result will show in my richComResults only the <item></item> occurred within these two dates.

Answer 1

You need to parse the date string in both xml and textbox value. Looks like your xml dates are in the RFC 1123 format so DateTime.Parse(itemDate) should work.
As for the textbox, this depends on the user and you can’t know for sure what is the format he uses. You can instruct him to enter dates in “dd/MM/yy” (this is what you used) and parse the date with DateTime.ParseExact.

using System.Globalization;

CultureInfo provider = CultureInfo.InvariantCulture;
if (DateTime.Parse(itemDate) >= DateTime.ParseExact(txtComStartDate.Text, "dd/MM/yy", provider))

I recommend you try to use a DateTimePicker. For more reading about DateTime format strings look here:
http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx