XmlClient Managed Provider

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• Download demo project - 9 Kb

Introduction

This is my first attempt at writing a Managed Provider. The idea behind it was to allow users of the Managed Provider to be able to fill DataSets from XML in a homogeneous way. This way you could mix XML and database data together without having to know exactly which is from which.

Usage Notes

• The Connection string for the XmlConnection class takes a URL or File path to an XML file.
• The XmlCommand class takes an optional XPath expression to decide which subset of the XML file to include in the DataSet.

Example

// call using: TestXml(@"c:\test.xml", "descendant::server[name='Kay']",
//                      "  ", "File Path with XPath Expression");

static void TestXml(string URL, string XPath, string indent, string Title)
{
  Console.WriteLine("Testing {0} \nwith XML Source: {1}", Title, URL);
  XmlDataAdapter da = new XmlDataAdapter(XPath, new XmlConnection(URL));

  da.SelectCommand.Connection.Open();
  DataSet ds = new DataSet();

  // Test Filling in with all data
  int rowsAffected = da.Fill(ds);
  Console.WriteLine(indent + "Filled DataSet with {0} rows", rowsAffected);
  string xml = ds.GetXml();

  // Test Filling with Schema only
  DataTable[] aTables = da.FillSchema(ds, SchemaType.Source);
  Console.WriteLine(indent + "Filled DataSet with {0} tables of Schema only",
                    aTables.GetLength(0));

  // Show XML if XPath is used
  if (XPath != "/") Console.WriteLine(indent + "XPath Results: \n{0}", xml);
}

Caveats

• The DataReader was never implemented.
• This Managed Provider is read-only. If you need to write with it, please contact me as I might be able to get something working.
• When using an XPath expression in the XmlCommand class, only the first Match is loaded into the DataSet.