Writing/Loading data to XML file C#

Question

I have an application in which a user will be saving information that will later be pulled up. Each 'Trial' will have its own XML file and within that XML file there will be specific events that are identified by an EventID and specific dogs competing in each event that will have their own DogID.

I need to find a way to check whether or not a specifric event or dog within a specific event has already been written to this file. Below is the code that will create this XML file for the very first time and then be updated when creates a specific event and dog for this file.

XmlWriter w = XmlWriter.Create(fs);

            w.WriteStartDocument();
            w.WriteStartElement("Event");
            for (int counter = 0; counter < registeredEventCount; counter++)
            {

                string eventString = registeredArrayList[counter].ToString();
                // eventString = eventString.Replace(" ", "");

                w.WriteStartElement("Event");
                w.WriteAttributeString("id", eventString);
                // Write a product.
                w.WriteStartElement("dogId");
                w.WriteElementString("eventID", eventSelectComboBox.SelectedItem.ToString());
                w.WriteElementString("ukcNumber", ukcDogNumTextBox.Text.ToString());
                w.WriteElementString("breed", breedTextBox.Text.ToString());
                w.WriteElementString("dogName", dogNameTextBox.Text.ToString());
                w.WriteEndElement();
                w.WriteEndElement();
            }

            w.WriteEndDocument();
            w.Flush();

Any suggestions? I am having trouble finding an effient way to check whether an event has already been created and a dog has already been created wihtin an event.

Can you keep a list of events/dogs during runtime? Then you only parse your XML file when you load your application and perform all further operations on a List<Dog> or List<Event>. An whenever you change your data you write the changes back to the XML file. — Jan
– Jan, Commented Aug 7, 2012 at 12:43

Felice Pollano · Accepted Answer · 2012-08-07 12:27:29Z

1

Use a Dictionary or an HashedSet populated during the file writing, check that dictionary for the proper key in order to check if the dog / event is already "seen" and to skip it.

answered Aug 7, 2012 at 12:27

Felice Pollano

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10 Comments

user1546315 Over a year ago

I haven never used Dictionary or a HashedSet. Could you provide any examples for me? I wouldn't know where to start with that suggestion.

Felice Pollano Over a year ago

@user1546315 start from here: dotnetperls.com/dictionary but you find a lot of code if you google for c# Dictionary

Felice Pollano Over a year ago

@Jan Dictionary<> or Hashedset<> allow a fast lookup

user1546315 Over a year ago

will the dictionary values remain after the program is closed and re-open. I need these values to always be there unless the user wants to delete the records.

Felice Pollano Over a year ago

@Jan yes in general, not if there is few elements: dotnetperls.com/dictionary-time

|

L.B · Accepted Answer · 2012-08-07 12:46:06Z

1

using XmlSerializer could be easier, For example

XmlSerializer serializer = new XmlSerializer(typeof(Trial));
serializer.Serialize(stream, trialObject);

public class Trial
{
    public List<Event> Events;
}

public class Event
{
    public string eventID;
    public string dogId;
    public string ukcNumber;
    public string breead;
    public string dogName;
}

answered Aug 7, 2012 at 12:46

L.B

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1 Comment

Robert H Over a year ago

+1 for showing how to use a List<Event> object. This is surprisingly elusive to find documentation for and used to cause me a great deal of grief trying to figure out properly. @user1546315 : Pay attention to this code, it is the method I use for dealing with XML.

h1ghfive · Accepted Answer · 2012-08-07 12:41:01Z

0

I think you need to take a look at LINQ to XML : http://msdn.microsoft.com/fr-fr/library/bb387098.aspx

This way you can query your XML document and retrieve what you need to check.

Side note : I recommend you to use the keyword 'using' to automtically Dispose() your streamWriter. Check this http://msdn.microsoft.com/fr-fr/library/yh598w02%28v=vs.80%29

You'll learn that basically, every class that implement IDisposable can be used with the using intruction.

answered Aug 7, 2012 at 12:41

h1ghfive

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