Applied XML Programming for Microsoft .NET.pdf - Csbdu.in

More documents

Recommendations

Info

The XPath Query EngineXPath is a language that allows you to navigate within XML documents. Think of XPathas a general-purpose query language for addressing, sorting, and filtering both theelements and the text of an XML document.The XPath notation is basically declarative. Any XPath expression is a path within theXML document that identifies the information with the given characteristics. The pathdefines a pattern, and the resulting selection includes all the nodes that match it. Theselection is expressed through a notation that emphasizes the hierarchical relationshipbetween the nodes. It works in much the same way files and folders work. For example,the XPath expression "book/publisher" means find the "publisher" element within the"book" element. The XPath navigation model works in the context of a hierarchy ofnodes in the XML document's tree. XPath makes use of a variation of theXmlDocument class, named XPathDocument.Running an XPath query is not actually different from executing a TransactSQL (T-SQL) query on SQL Server. Instead of getting back a collection of rows, a valid XPathexpression returns a collection of nodes. To scroll the returned nodes, you just use anXPath-customized version of a reader. We'll look at XPath in more detail in Chapter 6.ConclusionIn this chapter, we examined the building blocks of XML and explored the rationalebehind XML readers and writers—a new and innovative way to perform basicoperations on XML data sources. In the .NET Framework, XML readers introduce adatabase-like cursor model to navigate through data. The cursor model fallssomewhere between the well-known XMLDOM and SAX models. Not as expensive asXMLDOM and more programmer-friendly than SAX, the .NET Framework cursor modelpresents XML as just another data format you can work on using a familiar approach.As a developer, you are certainly familiar with I/O operations accomplished on a file ora database. Why should XML data sources be totally different? The node becomes justanother atomic element, along with the database row or the byte. Ad hoc methodsmake it possible for you to move through nodes in a straightforward, effective way.Readers and writers are not the only tools you can use to create XML-driven .NETapplications. Another group of classes work according to the specification of the W3CDOM. XSLT and XPath expressions are a pair of XML-related technologies that arepopular with developers and effective for arranging applications. In the .NETFramework, you find made-to-measure classes that make XML-to-XML transformationand query evaluation fast and easy.All the XML technologies introduced in this chapter will be covered in depth in thechapters that follow, beginning with XML readers in Chapter 2.Further ReadingThe W3C organization is currently working on a draft of the DOM Level 3 Core toinclude support for an abstract modeling schema and I/O serialization. Check out themost recent draft at http://www.w3.org/TR/2002/WD-DOM-Level3-ASLS-20020409. Theapproved standard—DOM Level 2 Core—is available at http://www.w3.org/TR/DOM-Level-2.Relevant information about XML standards is available from the W3C Web site, athttp://www.w3.org. If you want to learn more about the SAX specification, look at thenew Web site for the SAX project, at http://www.saxproject.org.19
A lot of useful developer-oriented documentation about XML is available on the Websites of the companies that support XML. In addition to the Microsoft Web site(http://msdn.microsoft.com/xml), check out the Intel Developer Services Web site(http://cedar.intel.com). In particular, you'll find an essential guide to XML in the .NETFramework: http://cedar.intel.com/media/pdf/dotnet/net_jumpstart.pdf.Finally, if you just want a good, all-encompassing book about XML programming, Iheartily recommend the Microsoft Press Core Reference book XML Programming(http://www.microsoft.com/mspress/books/4798.asp), by R. Allen Wyke, SultanRehman, and Brad Leupen (Microsoft Press, 2002). For a more general look into XMLas a unifying technology, Essential XML: Beyond Markup (Addison Wesley, 2000), byDon Box, Aaron Skonnard, and John Lam, is still one of the best books available.20
Page 2 and 3: Applied XML Programming for Microso
Page 4 and 5: services. Rainer Heller of Siemens
Page 6 and 7: IntroductionIt was about five years
Page 8 and 9: What Do I Need to Use This Book?Mos
Page 10 and 11: Part I: XML Core Classes in the .NE
Page 12 and 13: Related XML StandardsTable 1-1 list
Page 14 and 15: XMLDOM model (memory footprint and
Page 16 and 17: ⋮A configuration section handler
Page 18 and 19: managed application, you must first
Page 20 and 21: Figure 1-1: Streams can be read and
Page 22 and 23: abstraction and explicitly indicate
Page 26 and 27: Chapter 2: XML ReadersIn the Micros
Page 28 and 29: Table 2-1: Public Properties of the
Page 30 and 31: Table 2-3: Public Methods of the Xm
Page 32 and 33: Table 2-4: Types of Nodes in the Xm
Page 34 and 35: To produce these results, I created
Page 36 and 37: In particular, the XmlConvert class
Page 38 and 39: The method we create to do this is
Page 40 and 41: Consider the following attribute va
Page 42 and 43: An entity reference consists of the
Page 44 and 45: The NameTable ObjectOne of the secr
Page 46 and 47: End ClassByVal type As XmlNodeType)
Page 48 and 49: Fragments and Parser ContextThe con
Page 50 and 51: You can specify other settings for
Page 52 and 53: FullerAndrewSales ManagerLeverlingJ
Page 54 and 55: String[] m_headerValues;tokensbool
Page 56 and 57: get{if(m_readState != ReadState.Int
Page 58 and 59: }public override string this[string
Page 60 and 61: }}return false;The name of the attr
Page 62 and 63: dt.Columns.Add(col);}reader.MoveToE
Page 64 and 65: Readers and XML ReadersTo cap off o
Page 66 and 67: Chapter 3: XML Data ValidationOverv
Page 68 and 69: The XmlValidatingReader Programming
Page 70 and 71: The ValidationEventHandler EventThe
Page 72 and 73: Figure 3-1: The sample application
Page 74 and 75:
document, no event is fired, but an
Page 76 and 77:
valtype = "Auto.XDR";Figure 3-2 sho
Page 78 and 79:
validator object for further proces
Page 80 and 81:
);This method creates and adds a ne
Page 82 and 83:
public XmlValidatingReader(Stream,
Page 84 and 85:
XML InteroperabilityAs you can see,
Page 86 and 87:
XSDs are more powerful than DTDs, a
Page 88 and 89:
Compared to the DTD schema, this XD
Page 90 and 91:
xmlns:z='#RowsetSchema'>This simple
Page 93 and 94:
Figure 3-7: The XSD type hierarchy.
Page 95 and 96:
Table 3-6: Mapping Between XSD and
Page 97 and 98:
Table 3-7: Top-Level Elements for X
Page 99 and 100:
The next step is to define a new sc
Page 101 and 102:
Creating an XML Schema with Visual
Page 103 and 104:
Figure 3-10: The graphical represen
Page 105 and 106:
Open the XML readerXmlTextReader re
Page 107 and 108:
Define the pattern for the contentX
Page 109 and 110:
ody of the element. It is a simple
Page 111 and 112:
determine the correct sequence and
Page 113 and 114:
The root element can't be successfu
Page 115 and 116:
Francesco Balena's Programming Visu
Page 117 and 118:
}sw.Write(sb.ToString());sw.Close()
Page 119 and 120:
What the XmlWriter Class Can't DoAl
Page 121 and 122:
stream. Some working memory is free
Page 123 and 124:
Table 4-5: Miscellaneous Writing Me
Page 125 and 126:
If you want to get just the default
Page 127 and 128:
else you might need that the writer
Page 129 and 130:
By using the pubid argument (PUBLIC
Page 131 and 132:
Figure 4-3: A dynamically created X
Page 133 and 134:
This command executes normally, but
Page 135 and 136:
"dinoe:isbn-0735618011");This code
Page 137 and 138:
writer.WriteStartElement("element")
Page 139 and 140:
}writer.WriteEndDocument();writer.C
Page 141 and 142:
}}reader.Close();If in this code yo
Page 143 and 144:
Figure 4-8: A PictureBox control di
Page 145 and 146:
NoteThe entire source code for a sa
Page 147 and 148:
Table 4-8: Public Methods of the Xm
Page 149 and 150:
}Writer.WriteStartElement("xml");Wr
Page 151 and 152:
Testing the XmlRecordsetWriter Clas
Page 153 and 154:
Framework type and map each to an e
Page 155 and 156:
}if (i % 2)writer.WriteNode(reader,
Page 157 and 158:
Table 4-9: Methods of the XmlTextRe
Page 159 and 160:
while(rw.Read()){switch(rw.NodeType
Page 161 and 162:
if (m_reader.HasAttributes){// Cons
Page 163 and 164:
Figure 4-14: The code can be used t
Page 165 and 166:
}}rw.Writer.WriteStartElement(rw.Re
Page 167 and 168:
Note The new keyword is C#-specific
Page 169 and 170:
}The net effect of this code is tha
Page 171 and 172:
.NET XML writers only ensure the we
Page 173 and 174:
Part II: XML Data ManipulationChapt
Page 175 and 176:
3JanetLeverlingWhen processed by an
Page 177 and 178:
child elements when processing an X
Page 179 and 180:
through the base class XmlNode. (Se
Page 181 and 182:
Table 5-3: Events of the XmlDocumen
Page 183 and 184:
Both XmlLinkedNode and XmlCharacter
Page 185 and 186:
Figure 5-3: The XmlLinkedNode class
Page 187 and 188:
Working with XML DocumentsTo be ful
Page 189 and 190:
}}{if (n.NodeType == XmlNodeType.El
Page 191 and 192:
While the secondary thread works, t
Page 193 and 194:
Limitations of the XML DOM Eventing
Page 195 and 196:
XML document is often overkill unle
Page 197 and 198:
If you use a namespace, you might r
Page 199 and 200:
Extending the XML DOMAlthough the .
Page 201 and 202:
Table 5-6: Programming Interface of
Page 203 and 204:
file changes, irrespective of the c
Page 205 and 206:
Figure 5-7: The sample application
Page 207 and 208:
Chapter 6: XML Query Language and N
Page 209 and 210:
Figure 6-1: A sample XML tree in wh
Page 211 and 212:
with the forward slash (/). The fol
Page 213 and 214:
How XPointer Uses XPathAn XPointer
Page 215 and 216:
the caller. Using SelectSingleNode
Page 217 and 218:
StringBuilder sb = new StringBuilde
Page 219 and 220:
Figure 6-4: The node set returned b
Page 221 and 222:
A Better Way to Select a Single Nod
Page 223 and 224:
3. Optionally, precompile the XPath
Page 225 and 226:
Table 6-3: Properties of the XPathN
Page 227 and 228:
the type. In addition, attributes a
Page 229 and 230:
As you can see, several methods hav
Page 231 and 232:
Setting Namespace InformationThe in
Page 233 and 234:
string strX = (string) x;string str
Page 235 and 236:
the navigator's author must careful
Page 237 and 238:
⋮Notice that the sample file syst
Page 239 and 240:
Table 6-10: Properties of the XPath
Page 241 and 242:
supplies the underlying means to id
Page 243 and 244:
• XSL Formatting Objects (XSL-FO)
Page 245 and 246:
HTML," on page 299. In the meantime
Page 247 and 248:
Table 7-2: XSLT Instructions for Da
Page 249 and 250:
Table 7-4: XSLT Instructions for La
Page 251 and 252:
In the first template, the context
Page 253 and 254:
……⋮The expected target schema
Page 255 and 256:
By the way, note that the version a
Page 257 and 258:
The XslTransform ClassNow that we'v
Page 259 and 260:
To avoid threading risks, be aware
Page 261 and 262:
index of the style sheet contents.
Page 263 and 264:
Table 7-7: Transform Method Overloa
Page 265 and 266:
XSLT Output RecordsThe output of th
Page 267 and 268:
Perform the transformation, record
Page 269 and 270:
method, other attributes of interes
Page 271 and 272:
Table 7-8: Methods of the XsltArgum
Page 273 and 274:
the object's DataSetName property.
Page 275 and 276:
s:rowbaseAfter you create the node
Page 277 and 278:
features than the XslTransform clas
Page 279 and 280:
Don't confuse the Internet Explorer
Page 281 and 282:
Supported languages are C#, Visual
Page 283 and 284:
double CalculateSubTotal(XPathNodeI
Page 285 and 286:
profitable, because XML is a metala
Page 287 and 288:
Chapter 8: XML and DatabasesOvervie
Page 289 and 290:
Framework applications. SQLXML 3.0
Page 291 and 292:
......The FOR XML AUTO mode always
Page 293 and 294:
Figure 8-1: The client-side XML for
Page 295 and 296:
lastname AS [Employee!1!Name]This s
Page 297 and 298:
sql:field="FirstName" type="xsd:str
Page 299 and 300:
to instantiate a COM object, query
Page 301 and 302:
}// Process elementswhile(reader.Re
Page 303 and 304:
(No context information specified)X
Page 305 and 306:
}...The base class is for the most
Page 307 and 308:
public override void Close(){m_data
Page 309 and 310:
Synchronizing with a DataSet Object
Page 311 and 312:
denote insertions, deletions, and u
Page 313 and 314:
schema information to associate the
Page 315 and 316:
This schema first defines a relatio
Page 317 and 318:
that throughout the Updategram. The
Page 319 and 320:
object for XML-driven updates, an A
Page 321 and 322:
Table 8-2: Properties of the SqlXml
Page 323 and 324:
Table 8-4: Methods of the SqlXmlCom
Page 325 and 326:
This schema addresses a layout such
Page 327 and 328:
database. If all goes well, the Dat
Page 329 and 330:
Chapter 9: ADO.NET XML Data Seriali
Page 331 and 332:
provided way to serialize ADO.NET o
Page 333 and 334:
1DavolioNancy⋮106897⋮Basically,
Page 335 and 336:
The element describes the body of
Page 337 and 338:
Serializing to Valid XMLAs you can
Page 339 and 340:
Table 9-3: The MappingType Enumerat
Page 341 and 342:
⋮This syntax is simple and effect
Page 343 and 344:
By using keyref and nested types, y
Page 345 and 346:
Figure 9-6: An application that pas
Page 347 and 348:
{}DataTable dt = CreateTempTable(dv
Page 349 and 350:
dt = (DataTable) bf.Deserialize(sr.
Page 351 and 352:
more valuable, because it automatic
Page 353 and 354:
Loading DataSet Objects from XMLThe
Page 355 and 356:
The XML source is read one node aft
Page 357 and 358:
Figure 9-10: ReadXml correctly reco
Page 359 and 360:
Figure 9-12: How Microsoft Visual S
Page 361 and 362:
The reader tracks the current node
Page 363 and 364:
}m_currentAttributeIndex = -1;When
Page 365 and 366:
persistence, resort to the DiffGram
Page 367 and 368:
......The root node can have up to
Page 369 and 370:
object's tables. The data written o
Page 371 and 372:
different blocks. Attributes in the
Page 373 and 374:
If no match is found, ReadXml deduc
Page 375 and 376:
Although this solution is clearly n
Page 377 and 378:
The diffgr:error attribute on the r
Page 379 and 380:
{}// Url is a form property that po
Page 381 and 382:
...By design, the current DiffGram
Page 383 and 384:
a DiffGram. To make DiffGrams reall
Page 385 and 386:
Figure 10-8: The sample save-and-re
Page 387 and 388:
dv.RowStateFilter = DataViewRowStat
Page 389 and 390:
in the RowError property of the cor
Page 391 and 392:
however, the verbosity of XML paten
Page 393 and 394:
Chapter 11: XML SerializationOvervi
Page 395 and 396:
0As you can see, the class represen
Page 397 and 398:
ead-only properties; does not handl
Page 399 and 400:
}public Employee(){m_ID = -1;}publi
Page 401 and 402:
Methods of the XmlSerializer ClassT
Page 403 and 404:
ns.Add("d", "urn:dino-e-xml");ns.Ad
Page 405 and 406:
When designing classes destined to
Page 407 and 408:
eferenced assembly and its properti
Page 409 and 410:
The preceding code creates an attri
Page 411 and 412:
}public string FirstName;public str
Page 413 and 414:
XML as the type dictates. The attri
Page 415 and 416:
create the XmlSerializer object. Ho
Page 417 and 418:
command, the data flows into the se
Page 419 and 420:
XmlAttributes changesFirstName = ne
Page 421 and 422:
{if (emp.Territories == null)emp.Te
Page 423 and 424:
{// Import type mapping information
Page 425 and 426:
As you can see, the first file crea
Page 427 and 428:
A good source for learning about SO
Page 429 and 430:
NoteSome programmers believe that .
Page 431 and 432:
involved, you must use Web services
Page 433 and 434:
handled by .NET Remoting; the user
Page 435 and 436:
Figure 12-3: How .NET Remoting mars
Page 437 and 438:
If you want to play with the transp
Page 439 and 440:
The query involves three tables—E
Page 441 and 442:
As we saw in Chapter 4, the XmlText
Page 443 and 444:
{// Propertiesprotected SalesDataPr
Page 445 and 446:
We'll look more closely at channels
Page 447 and 448:
server only when the client calls a
Page 449 and 450:
Figure 12-5: The IIS application ma
Page 451 and 452:
this little requirement is enough t
Page 453 and 454:
typeof(ServiceSalesProvider),"tcp:/
Page 455 and 456:
}The code in boldface demonstrates
Page 457 and 458:
BinaryWriter writer = new BinaryWri
Page 459 and 460:
Chapter 13: XML Web ServicesOvervie
Page 461 and 462:
intSOAP is not magic—it is a simp
Page 463 and 464:
public class MyWebService : WebServ
Page 465 and 466:
effectively exposed over the Web, a
Page 467 and 468:
Format of SOAP Messages for a Web M
Page 469 and 470:
The SoapRpcMethod AttributeThe RPC
Page 471 and 472:
If you compare this code with the r
Page 473 and 474:
Figure 13-5: Processing a Web servi
Page 475 and 476:
The machine.config file is an XML f
Page 477 and 478:
Namespace="xmlnet/cs/0735618011")]p
Page 479 and 480:
In situations in which the URL can'
Page 481 and 482:
Const TheYear = 1997' Create the HT
Page 483 and 484:
implementation does make a lot of s
Page 485 and 486:
Mobile code allows you to send C# o
Page 487 and 488:
Chapter 14: XML on the ClientOvervi
Page 489 and 490:
accessible XML parser to consume th
Page 491 and 492:
The following code shows a version
Page 493 and 494:
NoteIn general, you can name the ou
Page 495 and 496:
To create a hidden field, you can u
Page 497 and 498:
To load assemblies from directories
Page 499 and 500:
{}int size = 130;this.Columns.Add(m
Page 501 and 502:
private void PrepareSortedDataView(
Page 503 and 504:
Figure 14-3: An ASP.NET page that c
Page 505 and 506:
var parser = new ActiveXObject("Mic
Page 507 and 508:
"SERVER=localhost;DATABASE=northwin
Page 509 and 510:
Chapter 15: .NET Framework Applicat
Page 511 and 512:
Because we're focusing on applicati
Page 513 and 514:
executable, ASP.NET application or
Page 515 and 516:
NoteUser applications don't need to
Page 517 and 518:
The myfile.config file contains the
Page 519 and 520:
Some internal variablesXmlNodeList
Page 521 and 522:
scratch or inherit from an existing
Page 523 and 524:
Table 15-2: Predefined Section Hand
Page 525 and 526:
The interface includes a single met
Page 527 and 528:
NameValueCollection coll;coll = Con
Page 529 and 530:
}if (configMenu != null)AddMenuTool
Page 531 and 532:
}}menuTools.MenuItems.Add(index, mn
Page 533 and 534:
Implementing the DataSet Section Ha
Page 535 and 536:
AfterwordOverviewWhile writing this
Page 537:
not an application-specific object.
show all

Applied XML Programming for Microsoft .NET.pdf - Csbdu.in

Create successful ePaper yourself

Delete template?

Save as template?