Strongly typed dataset to XML file problems

[Walt Borders]

Hi

I am new to xml and handling data in xml format.

I am able to read an XML file and schema into a DataGrid.

I can display the columns and values correctly using the
DataGridColumnStyle.

The problem is that when I write the dataSet to a file the nested
relation data does not nest correctly.

I've tried setting the relationship explicitly on the implicit
"tablename_id" column, but I receive an error telling me that a
relationship already exists.

I've dropped the relationship and added the new and receive a run-time
error: "A column name 'Rule' already belongs to this DataTable: cannot
set a nested table name to the same name.

There is a child table named "Rule". It is the child of a table name
"RuleList". There is no column named "Rule" in the DataSet.

At MSDN, and reading the "Nested DataRelations" in particular, it
seems that all I have to do is set NESTED = TRUE. Easier read than
done.

Any help/examples/correction will be very helpful.

Walt Borders



Code Snippets.

myDataSet = new DataSet();

myDataSet.ReadXmlSchema("ConfigSystem.xsd");

myDataSet.ReadXml("ConfigSystem.xml", XmlReadMode.ReadSchema);

this.dataGrid1.SetDataBinding(this.myDataSet,"Rule");


/// Display dataGrid1

/// Push button to Write the file

this.myDataSet.AcceptChanges();

// Re-Write the original file
string filename = "ConfigSystem.xml";

// Create the FileStream to write with.
System.IO.FileStream myFileStream = new System.IO.FileStream(filename,
System.IO.FileMode.Create);

// Create an XmlTextWriter with the fileStream.
System.Xml.XmlTextWriter myXmlWriter = new
System.Xml.XmlTextWriter(myFileStream, System.Text.Encoding.Unicode);
myXmlWriter.Formatting = Formatting.Indented;
myXmlWriter.Indentation = 3;

// Write to the file with the WriteXml method.
thisDataSet.WriteXml(myXmlWriter, XmlWriteMode.WriteSchema);

/// Done

 

[Guest]

Wal

There are two things I would verify her

Firstly, load the XML into an XmlDocument and write out its structure to a file, check to see if the XML is as expected

Secondly, check the MappingType for the columns in the DataSet, these can be set to be elements, attributes etc...

 

[Walt Borders]

Thanks Ian,

With success! I used your suggestion of loading the XML into an
XmlDocument. I also bound the dataGrid to the Parent of the 1:N implied
relationship.

For the record:

myDataSet = new DataSet();

myDataSet.ReadXmlSchema("ConfigSystem.xsd");

XmlDataDocument myXmlDocument = new XmlDataDocument(myDataSet);

myXmlDocument.Load("ConfigSystem.xml");

// Bind to the Parent (RuleList) of the Child (Rule):
// In the schema there is an implied 1:N relationship

this.dgRules.SetDataBinding(this.myDataSet,"RuleList");


/// Display dataGrid1

/// Push button to Write the file

this.myDataSet.AcceptChanges();

// Re-Write the original file
string filename = "ConfigSystem.xml";

this.myDataSet.WriteXml("ConfigSystem.xml", XmlWriteMode.WriteSchema);


Schema snippet:

<xs:element name="RuleList" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:element name="Rule" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:element name="Text" type="xs:string"/>
<xs:element name="alue" type="xs:string"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>