DataSet.WriteXml() - how to "drop" some fields - asp.net

Question

I've 2 questions:
First, I've a dataset with 5 tables. I've made the relationships of tables and generating an XML from this dataset like this:
StreamWriter xmlDoc = new StreamWriter("myxml.xml", false);
ds.WriteXml(xmlDoc);
xmlDoc.Close();
Some of the fields in each table in dataset are primary keys and I dont want to show them in XML. If I exclude them from tables, I cant make relationships. Can anybody give me some idea that how to write dataset to XML "droping" the key fields (columns in datatables)? For example, here is the XML generating at the moment:
<?xml version="1.0"?>
<o>
<sp spname="SP1" spid="8">
<event spid="8" eventname="Event1" eventId="482">
<bm bmname="BM1" bmid="2" bmeid="826" eventid="482">
<att bmeid="826" val="3.00" attname="Att1" atttype="Type1" attid="23172"/>
<att bmeid="826" val="3.50" attname="Att2" bettype="Type1" attid="23173"/>
</bm>
</event>
</sp>
</o>
but I want this XML to be generated like this (all id attributes should be "dropped" as all ids are for relationships and should not be added in XML):
<?xml version="1.0"?>
<o>
<sp spname="SP1">
<event eventname="Event1">
<bm bmname="BM1" bmid="2">
<att val="3.00" attname="Att1" atttype="Type1" />
<att val="3.50" attname="Att2" bettype="Type1" />
</bm>
</event>
</sp>
</o>
And now 2nd question:
I've given name to my dataset as "o" so its generating the xml as you can see above. I want to add some attributes to <o> node like current datetime. I mean I want <o> node to be genrated as <o generatedDate="09/13/2011" generatedTime="03:45 PM">. How can I achieve it?
Thanks,

Answer 1

You can hide the column to exclude it from the XML-File:
dataSet.Tables["TableName"].Columns["ColumnName"].ColumnMapping = MappingType.Hidden;

Answer 2

One option is to use LINQ to XML to alter the document. Another option would be to pass the XML into an XSLT transformer, which can parse the XML and output the desired results.
Transforming a DataSet using XSLT:
DataTable table = new DataTable();
System.IO.StringWriter writer = new System.IO.StringWriter();
//notice that we're ignoring the schema so we get clean XML back
//you can change the write mode as needed to get your result
table.WriteXml(writer, XmlWriteMode.IgnoreSchema, false);
string dataTableXml = writer.ToString();
As for displaying it in a readable format, I would suggest passing the XML into an XSL transformer, which you can then use to parse the XML and manipulate the output as needed.
Applying an XSLT Transform to a DataSet
http://msdn.microsoft.com/en-us/library/8fd7xytc%28v=vs.71%29.aspx#Y289
Here's a simple example I created to explain how you would use the XSL transformer. I haven't tested it, but it should be pretty close:
DataSet ds = new DataSet();
StringBuilder sbXslOutput = new StringBuilder();
using (XmlWriter xslWriter = XmlWriter.Create(sbXslOutput))
{
XslCompiledTransform transformer = new XslCompiledTransform();
transformer.Load("transformer.xsl");
XsltArgumentList args = new XsltArgumentList();
transformer.Transform(new XmlDataDocument(ds), args, xslWriter);
}
string dataSetHtml = sbXslOutput.ToString();
Formatting XML as HTML using XSLT
Here's an example of using XSLT to transform XML into an HTML table. It should be fairly easy to adopt so you can use it with your serialized DataSet.
Let's say this is your DataSet, serialized to XML:
<RecentMatter>
<UserLogin>PSLTP6\RJK</UserLogin>
<MatterNumber>99999-2302</MatterNumber>
<ClientName>Test Matters</ClientName>
<MatterName>DP Test Matter</MatterName>
<ClientCode>99999</ClientCode>
<OfficeCode/>
<OfficeName/>
<Billable>true</Billable>
<ReferenceId/>
<LastUsed>2011-08-23T23:40:24.13+01:00</LastUsed>
</RecentMatter>
<RecentMatter>
<UserLogin>PSLTP6\RJK</UserLogin>
<MatterNumber>999991.0002</MatterNumber>
<ClientName>Lathe 1</ClientName>
<MatterName>LW Test 2</MatterName>
<ClientCode/>
<OfficeCode/>
<OfficeName/>
<Billable>true</Billable>
<ReferenceId/>
<LastUsed>2011-07-12T16:57:27.173+01:00</LastUsed>
</RecentMatter>
<RecentMatter>
<UserLogin>PSLTP6\RJK</UserLogin>
<MatterNumber>999991-0001</MatterNumber>
<ClientName>Lathe 1</ClientName>
<MatterName>LW Test 1</MatterName>
<ClientCode/>
<OfficeCode/>
<OfficeName/>
<Billable>false</Billable>
<ReferenceId/>
<LastUsed>2011-07-12T01:59:06.887+01:00</LastUsed>
</RecentMatter>
</NewDataSet>
Here's an XSLT script that transforms the DataSet to HTML:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:template match="/">
<table border="1">
<tr>
<th>User Login</th>
<th>Matter Number</th>
...
</tr>
<xsl:for-each select="NewDataSet/RecentMatter">
<tr>
<td>
<xsl:value-of select="UserLogin"/>
</td>
<td>
<xsl:value-of select="MatterNumber"/>
</td>
...
</tr>
</xsl:for-each>
</table>
</xsl:template>
</xsl:stylesheet>

Answer 3

I would suggest after generating the XML, use LINQ to XML to filter out / add attribute to desired nodes. This filtering and adding attribute is a separate step then generating the XML from data set and should be handled after the XML is generated from data set as that would lead to better design.