Filling comboBox from an XML File

kuznickic · August 25th, 2007, 06:46 PM

Hi all,

Okay I have an XML file that has values in it that I want to populate in a text box. Basically this is the xml file looks.

Code:

<?xml version="1.0" encoding="utf-8"?>
<rs:data xmlns:rs="urn:schemas-microsoft-com:rowset">
  <row name="Some feed" value="somefeed.coolfeed.com/topstories.xml"></row>
</rs:data>

The other set of code that I am populating the comboBox is

Code:

private void BindComboBox()
{
    string dsFileName = "Feeds.xml";
    DataSet dsFeeds = new DataSet();
    dsFeeds.ReadXml(dsFileName);
    comboBox1.DataSource = dsFeeds;
    comboBox1.DisplayMember = "row.name";
    comboBox1.ValueMember = "row.value";
}

Now when I took out the fourth line in the second code block, I noticed that there were problems with my xml file. Basically when I went to build the application, there were problems with finding the schema information for row, name, and value. Where could I be going wrong?
Please, please help.
Chris

kuznickic · August 26th, 2007, 03:43 PM

Hi all,

I think I am just too stupid to figure this out but it has taken me days and I still cant figure out what I am doing wrong. Basically this is a WinForm RSS Reader. I am trying to save the feeds that the user is subscribed to in an xml file that is deployed with the app. I just want those values inside of the file along with the name of those values to be tied to a comboBox control. Basically the names will appear and when the user selects a name I can use the value to point to a feed. Please, please, please tell me where I am going wrong. This problem is very aggravating. I know this shouldn't be all that hard.

Thanks,
Chris

planoie · August 26th, 2007, 09:09 PM

If your XML file is indeed a dataset, you shouldn't need to do much of anything special. You shouldn't need (and I don't believe you can) prefix the DisplayMember or ValueMember of the combobox. Have you set a breakpoint after the ReadXml call and looked at the contents of the dataset to verify that it's reading in the data correctly?

-Peter

kuznickic · August 27th, 2007, 04:31 AM

Thanks for the reply.
Okay, basically this file is part of my project. How can I be sure that this data is being put into the dataset? I am used to databases and not XML so please be patient. Is there a better way to write my XML file and is a schema necessary? And how do I navigate to the nodes that I want to be the values and names for the comboBox control? I am assuming that for the values and names that I will use XPath to navigate to those values but am not sure. I have changed my XML file to this

Code:

<?xml version="1.0">
<Feeds>
   <Feed>name of the feed
       <Location>url of feed</Location>
   </Feed>
</Feeds>

Pretty much I want to use feed element as the name and location element as the value. Is this workable? Please advise. Your help is greatly appreciated.
Thanks
Chris

planoie · August 27th, 2007, 08:10 PM

I wasn't implying anything was wrong with your original XML file. My concern was that it was being properly loaded into a dataset. If it is, then it's easy to bind that to a control. If you want to work with XML as XML then you need to use one of the xml classes (XmlDocument, XmlTextReader). This complicates things slightly.

-Peter

kuznickic · August 28th, 2007, 04:14 AM

Thank you so much for the reply.
Basically , it doesn't matter which way I want to read the XML data whether through a typed dataset or directly. Whichever way is the easiest. I know how to add a dataset object to a form, but how do I ensure that it is typed? Please any assistance would be greatly appreciated.

Thanks
Chris

kuznickic · August 28th, 2007, 07:01 AM

Hi Peter,

Okay I rewrote my code with some success.
Basically this is what I have

Code:

public partial class frmMain : Form
{

      public frmMain()
      {

      InitializeComponent();

      string dfFeeds = "Feeds.xml";

      dsFeeds.ReadXml(dfFeeds);

      cboFeeds.DataSource = dsFeeds.Tables[0];
      cboFeeds.DisplayMember = "name";
      cboFeeds.ValueMember = "location";

      }
}

And for the XML file

Code:

<?xml version = "1.0"?>
<Feeds>
   <Feed>
      <name></name>
      <location></location>
   </Feed>
   <Feed>
       <name></name>
       <location></location>
   </Feed>
</Feeds>

I say limited success because the first Feed element items appear in the comboBox but not the second. Do I need a foreach loop? Any help would be greatly appreciated.

Thanks
Chris

planoie · August 28th, 2007, 08:00 AM

Maybe this series of articles will help you:

http://samples.gotdotnet.com/quickst...MLDataSet.aspx

-Peter

kuznickic · August 28th, 2007, 10:32 AM

Thanks very much Peter,

That gives me a good start. But I'm stuck again. Here is my code
[code]
XmlDataDocument feedsXml = new XmlDataDocument();
feedsXml.DataSet.ReadXml(new StreamReader("Feeds.xml"), XmlReadMode.InferSchema);

cboFeeds.DataSource = feedsXml
cboFeeds.DisplayMember = feedsXml.DataSet.Tables[0].Columns[0];
cboFeeds.ValueMember = feedsXml.DataSet.Tables[0].Columns[1];
[\code]

It is saying cannot implicitly convert to string value. I know that display member and value members are string values. So how do I read those values out of the DataSet? And where do I name the dataset. The examples were pretty vague on that detail. Thanks again.

Chris

dparsons · August 28th, 2007, 10:46 AM

Change these lines:
cboFeeds.DisplayMember = feedsXml.DataSet.Tables[0].Columns[0];
cboFeeds.ValueMember = feedsXml.DataSet.Tables[0].Columns[1];

to this:
cboFeeds.DisplayMember = feedsXml.DataSet.Tables[0].Columns[0].Caption.ToString()
cboFeeds.ValueMember = feedsXml.DataSet.Tables[0].Columns[1].Caption.ToString();

that should do the trick.

hth.

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