1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
| Imports System
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.ComponentModel.Design.Serialization
Imports System.Collections
Imports System.Diagnostics
Imports System.Globalization
Imports System.IO
Imports System.Reflection
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Windows.Forms
Imports System.Xml
Imports System.Runtime.InteropServices
Namespace Loader
''' <summary>
''' Inherits from BasicDesignerLoader. It can persist the HostSurface
''' to an Xml file and can also parse the Xml file to re-create the
''' RootComponent and all the components that it hosts.
''' </summary>
Friend Class BasicHostLoader
Inherits BasicDesignerLoader
Private root As IComponent
Private dirty As Boolean = True
Private unsaved As Boolean
Private fileName As String
Private host As IDesignerLoaderHost
Private xmlDocument As XmlDocument
Private Shared ReadOnly propertyAttributes As Object = New Attribute() {DesignOnlyAttribute.No}
Private rootComponentType As Type
#Region "Constructors"
''' Empty constructor simply creates a new form.
Public Sub New(ByVal rootComponentType As Type)
Me.rootComponentType = rootComponentType
Modified = True
End Sub
''' <summary>
''' This constructor takes a file name. This file
''' should exist on disk and consist of XML that
''' can be read by a data set.
''' </summary>
Public Sub New(ByVal fileName As String)
If Equals(fileName, Nothing) Then
Throw New ArgumentNullException("fileName")
End If
Me.fileName = fileName
End Sub
#End Region
#Region "Overriden methods of BasicDesignerLoader"
' Called by the host when we load a document.
Protected Overrides Sub PerformLoad(ByVal designerSerializationManager As IDesignerSerializationManager)
host = LoaderHost
If host Is Nothing Then
Throw New ArgumentNullException("BasicHostLoader.BeginLoad: Invalid designerLoaderHost.")
End If
' The loader will put error messages in here.
Dim errors As ArrayList = New ArrayList()
Dim successful = True
Dim baseClassName As String
' If no filename was passed in, just create a form and be done with it. If a file name
' was passed, read it.
If Equals(fileName, Nothing) Then
If rootComponentType Is GetType(Form) Then
host.CreateComponent(GetType(Form))
baseClassName = "Form1"
ElseIf rootComponentType Is GetType(UserControl) Then
host.CreateComponent(GetType(UserControl))
baseClassName = "UserControl1"
ElseIf rootComponentType Is GetType(Component) Then
host.CreateComponent(GetType(Component))
baseClassName = "Component1"
Else
Throw New Exception("Undefined Host Type: " & rootComponentType.ToString())
End If
Else
baseClassName = ReadFile(fileName, errors, xmlDocument)
End If
' Now that we are done with the load work, we need to begin to listen to events.
' Listening to event notifications is how a designer "Loader" can also be used
' to save data. If we wanted to integrate this loader with source code control,
' we would listen to the "ing" events as well as the "ed" events.
Dim cs As IComponentChangeService = TryCast(host.GetService(GetType(IComponentChangeService)), IComponentChangeService)
If cs IsNot Nothing Then
AddHandler cs.ComponentChanged, New ComponentChangedEventHandler(AddressOf OnComponentChanged)
AddHandler cs.ComponentAdded, New ComponentEventHandler(AddressOf OnComponentAddedRemoved)
AddHandler cs.ComponentRemoved, New ComponentEventHandler(AddressOf OnComponentAddedRemoved)
End If
' Let the host know we are done loading.
host.EndLoad(baseClassName, successful, errors)
' We've just loaded a document, so you can bet we need to flush changes.
dirty = True
unsaved = False
End Sub
''' <summary>
''' This method is called by the designer host whenever it wants the
''' designer loader to flush any pending changes. Flushing changes
''' does not mean the same thing as saving to disk. For example,
''' In Visual Studio, flushing changes causes new code to be generated
''' and inserted into the text editing window. The user can edit
''' the new code in the editing window, but nothing has been saved
''' to disk. This sample adheres to this separation between flushing
''' and saving, since a flush occurs whenever the code windows are
''' displayed or there is a build. Neither of those items demands a save.
''' </summary>
Protected Overrides Sub PerformFlush(ByVal designerSerializationManager As IDesignerSerializationManager)
' Nothing to flush if nothing has changed.
If Not dirty Then
Return
End If
PerformFlushWorker()
End Sub
Public Overrides Sub Dispose()
' Always remove attached event handlers in Dispose.
Dim cs As IComponentChangeService = TryCast(host.GetService(GetType(IComponentChangeService)), IComponentChangeService)
If cs IsNot Nothing Then
RemoveHandler cs.ComponentChanged, New ComponentChangedEventHandler(AddressOf OnComponentChanged)
RemoveHandler cs.ComponentAdded, New ComponentEventHandler(AddressOf OnComponentAddedRemoved)
RemoveHandler cs.ComponentRemoved, New ComponentEventHandler(AddressOf OnComponentAddedRemoved)
End If
End Sub
#End Region
#Region "Helper methods"
''' <summary>
''' Simple helper method that returns true if the given type converter supports
''' two-way conversion of the given type.
''' </summary>
Private Function GetConversionSupported(ByVal converter As TypeConverter, ByVal conversionType As Type) As Boolean
Return converter.CanConvertFrom(conversionType) AndAlso converter.CanConvertTo(conversionType)
End Function
''' <summary>
''' As soon as things change, we're dirty, so Flush()ing will give us a new
''' xmlDocument and codeCompileUnit.
''' </summary>
Private Sub OnComponentChanged(ByVal sender As Object, ByVal ce As ComponentChangedEventArgs)
dirty = True
unsaved = True
End Sub
Private Sub OnComponentAddedRemoved(ByVal sender As Object, ByVal ce As ComponentEventArgs)
dirty = True
unsaved = True
End Sub
''' <summary>
''' This method prompts the user to see if it is OK to dispose this document.
''' The prompt only happens if the user has made changes.
''' </summary>
Friend Function PromptDispose() As Boolean
If dirty OrElse unsaved Then
Select Case MessageBox.Show("Save changes to existing designer?", "Unsaved Changes", MessageBoxButtons.YesNoCancel)
Case DialogResult.Yes
Save(False)
Case DialogResult.Cancel
Return False
End Select
End If
Return True
End Function
#End Region
#Region "Serialize - Flush"
''' <summary>
''' This will recussively go through all the objects in the tree and
''' serialize them to Xml
''' </summary>
Public Sub PerformFlushWorker()
Dim document As XmlDocument = New XmlDocument()
document.AppendChild(document.CreateElement("DOCUMENT_ELEMENT"))
Dim idh = CType(host.GetService(GetType(IDesignerHost)), IDesignerHost)
root = idh.RootComponent
Dim nametable As Hashtable = New Hashtable(idh.Container.Components.Count)
Dim manager As IDesignerSerializationManager = TryCast(host.GetService(GetType(IDesignerSerializationManager)), IDesignerSerializationManager)
document.DocumentElement.AppendChild(WriteObject(document, nametable, root))
For Each comp As IComponent In idh.Container.Components
If comp IsNot root AndAlso Not nametable.ContainsKey(comp) Then
document.DocumentElement.AppendChild(WriteObject(document, nametable, comp))
End If
Next
xmlDocument = document
End Sub
Private Function WriteObject(ByVal document As XmlDocument, ByVal nametable As IDictionary, ByVal value As Object) As XmlNode
Dim idh = CType(host.GetService(GetType(IDesignerHost)), IDesignerHost)
Debug.Assert(value IsNot Nothing, "Should not invoke WriteObject with a null value")
Dim node As XmlNode = document.CreateElement("Object")
Dim typeAttr = document.CreateAttribute("type")
typeAttr.Value = value.GetType().AssemblyQualifiedName
node.Attributes.Append(typeAttr)
Dim component As IComponent = TryCast(value, IComponent)
If component IsNot Nothing AndAlso component.Site IsNot Nothing AndAlso Not Equals(component.Site.Name, Nothing) Then
Dim nameAttr = document.CreateAttribute("name")
nameAttr.Value = component.Site.Name
node.Attributes.Append(nameAttr)
Debug.Assert(nametable(component) Is Nothing, "WriteObject should not be called more than once for the same object. Use WriteReference instead")
nametable(value) = component.Site.Name
End If
Dim isControl = TypeOf value Is Control
If isControl Then
Dim childAttr = document.CreateAttribute("children")
childAttr.Value = "Controls"
node.Attributes.Append(childAttr)
End If
If component IsNot Nothing Then
If isControl Then
For Each child As Control In CType(value, Control).Controls
If child.Site IsNot Nothing AndAlso child.Site.Container Is idh.Container Then
node.AppendChild(WriteObject(document, nametable, child))
End If
Next
End If ' if isControl
Dim properties As PropertyDescriptorCollection = TypeDescriptor.GetProperties(value, propertyAttributes)
If isControl Then
Dim controlProp = properties("Controls")
If controlProp IsNot Nothing Then
Dim propArray = New PropertyDescriptor(properties.Count - 1 - 1) {}
Dim idx = 0
For Each p As PropertyDescriptor In properties
If p IsNot controlProp Then
propArray(Math.Min(Threading.Interlocked.Increment(idx), idx - 1)) = p
End If
Next
properties = New PropertyDescriptorCollection(propArray)
End If
End If
WriteProperties(document, properties, value, node, "Property")
Dim events As EventDescriptorCollection = TypeDescriptor.GetEvents(value, propertyAttributes)
Dim bindings As IEventBindingService = TryCast(host.GetService(GetType(IEventBindingService)), IEventBindingService)
If bindings IsNot Nothing Then
properties = bindings.GetEventProperties(events)
WriteProperties(document, properties, value, node, "Event")
End If
Else
WriteValue(document, value, node)
End If
Return node
End Function
Private Sub WriteProperties(ByVal document As XmlDocument, ByVal properties As PropertyDescriptorCollection, ByVal value As Object, ByVal parent As XmlNode, ByVal elementName As String)
For Each prop As PropertyDescriptor In properties
If Equals(prop.Name, "AutoScaleBaseSize") Then
Dim _DEBUG_ = prop.Name
End If
If prop.ShouldSerializeValue(value) Then
Dim compName = parent.Name
Dim node As XmlNode = document.CreateElement(elementName)
Dim attr = document.CreateAttribute("name")
attr.Value = prop.Name
node.Attributes.Append(attr)
Dim visibility = CType(prop.Attributes(GetType(DesignerSerializationVisibilityAttribute)), DesignerSerializationVisibilityAttribute)
Select Case visibility.Visibility
Case DesignerSerializationVisibility.Visible
If Not prop.IsReadOnly AndAlso WriteValue(document, prop.GetValue(value), node) Then
parent.AppendChild(node)
End If
Case DesignerSerializationVisibility.Content
Dim propValue = prop.GetValue(value)
If GetType(IList).IsAssignableFrom(prop.PropertyType) Then
WriteCollection(document, CType(propValue, IList), node)
Else
Dim props = TypeDescriptor.GetProperties(propValue, propertyAttributes)
WriteProperties(document, props, propValue, node, elementName)
End If
If node.ChildNodes.Count > 0 Then
parent.AppendChild(node)
End If
Case Else
End Select
End If
Next
End Sub
Private Function WriteReference(ByVal document As XmlDocument, ByVal value As IComponent) As XmlNode
Dim idh = CType(host.GetService(GetType(IDesignerHost)), IDesignerHost)
Debug.Assert(value IsNot Nothing AndAlso value.Site IsNot Nothing AndAlso value.Site.Container Is idh.Container, "Invalid component passed to WriteReference")
Dim node As XmlNode = document.CreateElement("Reference")
Dim attr = document.CreateAttribute("name")
attr.Value = value.Site.Name
node.Attributes.Append(attr)
Return node
End Function
Public LeCode As String
Private Function WriteValue(ByVal document As XmlDocument, ByVal value As Object, ByVal parent As XmlNode) As Boolean
Dim idh = CType(host.GetService(GetType(IDesignerHost)), IDesignerHost)
' For empty values, we just return. This creates an empty node.
If value Is Nothing Then
Return True
End If
Dim converter = TypeDescriptor.GetConverter(value)
If GetConversionSupported(converter, GetType(String)) Then
parent.InnerText = CStr(converter.ConvertTo(Nothing, CultureInfo.InvariantCulture, value, GetType(String)))
ElseIf GetConversionSupported(converter, GetType(Byte())) Then
Dim data = CType(converter.ConvertTo(Nothing, CultureInfo.InvariantCulture, value, GetType(Byte())), Byte())
parent.AppendChild(WriteBinary(document, data))
ElseIf GetConversionSupported(converter, GetType(InstanceDescriptor)) Then
Dim id = CType(converter.ConvertTo(Nothing, CultureInfo.InvariantCulture, value, GetType(InstanceDescriptor)), InstanceDescriptor)
parent.AppendChild(WriteInstanceDescriptor(document, id, value))
ElseIf TypeOf value Is IComponent AndAlso CType(value, IComponent).Site IsNot Nothing AndAlso CType(value, IComponent).Site.Container Is idh.Container Then
parent.AppendChild(WriteReference(document, CType(value, IComponent)))
ElseIf value.GetType().IsSerializable Then
Dim formatter As BinaryFormatter = New BinaryFormatter()
Dim stream As MemoryStream = New MemoryStream()
formatter.Serialize(stream, value)
Dim binaryNode As XmlNode = WriteBinary(document, stream.ToArray())
parent.AppendChild(binaryNode)
Else
Return False
End If
Return True
End Function
Private Sub WriteCollection(ByVal document As XmlDocument, ByVal list As IList, ByVal parent As XmlNode)
For Each obj In list
Dim node As XmlNode = document.CreateElement("Item")
Dim typeAttr = document.CreateAttribute("type")
typeAttr.Value = obj.GetType().AssemblyQualifiedName
node.Attributes.Append(typeAttr)
WriteValue(document, obj, node)
parent.AppendChild(node)
Next
End Sub
Private Function WriteBinary(ByVal document As XmlDocument, ByVal value As Byte()) As XmlNode
Dim node As XmlNode = document.CreateElement("Binary")
node.InnerText = Convert.ToBase64String(value)
Return node
End Function
Private Function WriteInstanceDescriptor(ByVal document As XmlDocument, ByVal desc As InstanceDescriptor, ByVal value As Object) As XmlNode
Dim node As XmlNode = document.CreateElement("InstanceDescriptor")
Dim formatter As BinaryFormatter = New BinaryFormatter()
Dim stream As MemoryStream = New MemoryStream()
formatter.Serialize(stream, desc.MemberInfo)
Dim memberAttr = document.CreateAttribute("member")
memberAttr.Value = Convert.ToBase64String(stream.ToArray())
node.Attributes.Append(memberAttr)
For Each arg In desc.Arguments
Dim argNode As XmlNode = document.CreateElement("Argument")
If WriteValue(document, arg, argNode) Then
node.AppendChild(argNode)
End If
Next
If Not desc.IsComplete Then
Dim props = TypeDescriptor.GetProperties(value, propertyAttributes)
WriteProperties(document, props, value, node, "Property")
End If
Return node
End Function
#End Region
#Region "DeSerialize - Load"
''' <summary>
''' This method is used to parse the given file. Before calling this
''' method the host member variable must be setup. This method will
''' create a data set, read the data set from the XML stored in the
''' file, and then walk through the data set and create components
''' stored within it. The data set is stored in the persistedData
''' member variable upon return.
'''
''' This method never throws exceptions. It will set the successful
''' ref parameter to false when there are catastrophic errors it can't
''' resolve (like being unable to parse the XML). All error exceptions
''' are added to the errors array list, including minor errors.
''' </summary>
Private Function ReadFile(ByVal fileName As String, ByVal errors As ArrayList, <Out> ByRef document As XmlDocument) As String
Dim baseClass As String = Nothing
' Anything unexpected is a fatal error.
'
Try
' The main form and items in the component tray will be at the
' same level, so we have to create a higher super-root in order
' to construct our XmlDocument.
Dim sr As StreamReader = New StreamReader(fileName)
Dim cleandown As String = sr.ReadToEnd()
cleandown = "<DOCUMENT_ELEMENT>" & cleandown & "</DOCUMENT_ELEMENT>"
Dim doc As XmlDocument = New XmlDocument()
doc.LoadXml(cleandown)
' Now, walk through the document's elements.
'
For Each node As XmlNode In doc.DocumentElement.ChildNodes
If Equals(baseClass, Nothing) Then
baseClass = node.Attributes("name").Value
End If
If node.Name.Equals("Object") Then
ReadObject(node, errors)
Else
errors.Add(String.Format("Node type {0} is not allowed here.", node.Name))
End If
Next
document = doc
Catch ex As Exception
document = Nothing
errors.Add(ex)
End Try
Return baseClass
End Function
Private Sub ReadEvent(ByVal childNode As XmlNode, ByVal instance As Object, ByVal errors As ArrayList)
Dim bindings As IEventBindingService = TryCast(host.GetService(GetType(IEventBindingService)), IEventBindingService)
If bindings Is Nothing Then
errors.Add("Unable to contact event binding service so we can't bind any events")
Return
End If
Dim nameAttr = childNode.Attributes("name")
If nameAttr Is Nothing Then
errors.Add("No event name")
Return
End If
Dim methodAttr = childNode.Attributes("method")
If methodAttr Is Nothing OrElse Equals(methodAttr.Value, Nothing) OrElse methodAttr.Value.Length = 0 Then
errors.Add(String.Format("Event {0} has no method bound to it"))
Return
End If
Dim evt = TypeDescriptor.GetEvents(instance)(nameAttr.Value)
If evt Is Nothing Then
errors.Add(String.Format("Event {0} does not exist on {1}", nameAttr.Value, instance.GetType().FullName))
Return
End If
Dim prop = bindings.GetEventProperty(evt)
Debug.Assert(prop IsNot Nothing, "Bad event binding service")
Try
prop.SetValue(instance, methodAttr.Value)
Catch ex As Exception
errors.Add(ex.Message)
End Try
End Sub
Private Function ReadInstanceDescriptor(ByVal node As XmlNode, ByVal errors As ArrayList) As Object
' First, need to deserialize the member
'
Dim memberAttr = node.Attributes("member")
If memberAttr Is Nothing Then
errors.Add("No member attribute on instance descriptor")
Return Nothing
End If
Dim data = Convert.FromBase64String(memberAttr.Value)
Dim formatter As BinaryFormatter = New BinaryFormatter()
Dim stream As MemoryStream = New MemoryStream(data)
Dim mi = CType(formatter.Deserialize(stream), MemberInfo)
Dim args As Object() = Nothing
' Check to see if this member needs arguments. If so, gather
' them from the XML.
If TypeOf mi Is MethodBase Then
Dim paramInfos As ParameterInfo() = CType(mi, MethodBase).GetParameters()
args = New Object(paramInfos.Length - 1) {}
Dim idx = 0
For Each child As XmlNode In node.ChildNodes
If child.Name.Equals("Argument") Then
Dim value As Object
If Not ReadValue(child, TypeDescriptor.GetConverter(paramInfos(idx).ParameterType), errors, value) Then
Return Nothing
End If
args(Math.Min(Threading.Interlocked.Increment(idx), idx - 1)) = value
End If
Next
If idx <> paramInfos.Length Then
errors.Add(String.Format("Member {0} requires {1} arguments, not {2}.", mi.Name, args.Length, idx))
Return Nothing
End If
End If
Dim id As InstanceDescriptor = New InstanceDescriptor(mi, args)
Dim instance As Object = id.Invoke()
' Ok, we have our object. Now, check to see if there are any properties, and if there are,
' set them.
'
For Each prop As XmlNode In node.ChildNodes
If prop.Name.Equals("Property") Then
ReadProperty(prop, instance, errors)
End If
Next
Return instance
End Function
''' Reads the "Object" tags. This returns an instance of the
''' newly created object. Returns null if there was an error.
Private Function ReadObject(ByVal node As XmlNode, ByVal errors As ArrayList) As Object
Dim typeAttr = node.Attributes("type")
If typeAttr Is Nothing Then
errors.Add("<Object> tag is missing required type attribute")
Return Nothing
End If
Dim type = System.Type.GetType(typeAttr.Value)
If type Is Nothing Then
errors.Add(String.Format("Type {0} could not be loaded.", typeAttr.Value))
Return Nothing
End If
' This can be null if there is no name for the object.
'
Dim nameAttr = node.Attributes("name")
Dim instance As Object
If GetType(IComponent).IsAssignableFrom(type) Then
If nameAttr Is Nothing Then
instance = host.CreateComponent(type)
Else
instance = host.CreateComponent(type, nameAttr.Value)
End If
Else
instance = Activator.CreateInstance(type)
End If
' Got an object, now we must process it. Check to see if this tag
' offers a child collection for us to add children to.
'
Dim childAttr = node.Attributes("children")
Dim childList As IList = Nothing
If childAttr IsNot Nothing Then
Dim childProp = TypeDescriptor.GetProperties(instance)(childAttr.Value)
If childProp Is Nothing Then
errors.Add(String.Format("The children attribute lists {0} as the child collection but this is not a property on {1}", childAttr.Value, instance.GetType().FullName))
Else
childList = TryCast(childProp.GetValue(instance), IList)
If childList Is Nothing Then
errors.Add(String.Format("The property {0} was found but did not return a valid IList", childProp.Name))
End If
End If
End If
' Now, walk the rest of the tags under this element.
'
For Each childNode As XmlNode In node.ChildNodes
If childNode.Name.Equals("Object") Then
' Another object. In this case, create the object, and
' parent it to ours using the children property. If there
' is no children property, bail out now.
If childAttr Is Nothing Then
errors.Add("Child object found but there is no children attribute")
Continue For
End If
' no sense doing this if there was an error getting the property. We've already reported the
' error above.
If childList IsNot Nothing Then
Dim childInstance = ReadObject(childNode, errors)
childList.Add(childInstance)
End If
ElseIf childNode.Name.Equals("Property") Then
' A property. Ask the property to parse itself.
'
ReadProperty(childNode, instance, errors)
ElseIf childNode.Name.Equals("Event") Then
' An event. Ask the event to parse itself.
'
ReadEvent(childNode, instance, errors)
End If
Next
Return instance
End Function
''' Parses the given XML node and sets the resulting property value.
Private Sub ReadProperty(ByVal node As XmlNode, ByVal instance As Object, ByVal errors As ArrayList)
Dim nameAttr = node.Attributes("name")
If nameAttr Is Nothing Then
errors.Add("Property has no name")
Return
End If
Dim prop = TypeDescriptor.GetProperties(instance)(nameAttr.Value)
If prop Is Nothing Then
errors.Add(String.Format("Property {0} does not exist on {1}", nameAttr.Value, instance.GetType().FullName))
Return
End If
' Get the type of this property. We have three options:
' 1. A normal read/write property.
' 2. A "Content" property.
' 3. A collection.
'
Dim isContent = prop.Attributes.Contains(DesignerSerializationVisibilityAttribute.Content)
If isContent Then
Dim value = prop.GetValue(instance)
' Handle the case of a content property that is a collection.
'
If TypeOf value Is IList Then
For Each child As XmlNode In node.ChildNodes
If child.Name.Equals("Item") Then
Dim item As Integer
Dim typeAttr = child.Attributes("type")
If typeAttr Is Nothing Then
errors.Add("Item has no type attribute")
Continue For
End If
Dim type = System.Type.GetType(typeAttr.Value)
If type Is Nothing Then
errors.Add(String.Format("Item type {0} could not be found.", typeAttr.Value))
Continue For
End If
If ReadValue(child, TypeDescriptor.GetConverter(type), errors, item) Then
Try
CType(value, IList).Add(item)
Catch ex As Exception
errors.Add(ex.Message)
End Try
End If
Else
errors.Add(String.Format("Only Item elements are allowed in collections, not {0} elements.", child.Name))
End If
Next
Else
' Handle the case of a content property that consists of child properties.
'
For Each child As XmlNode In node.ChildNodes
If child.Name.Equals("Property") Then
ReadProperty(child, value, errors)
Else
errors.Add(String.Format("Only Property elements are allowed in content properties, not {0} elements.", child.Name))
End If
Next
End If
Else
Dim value As Integer
If ReadValue(node, prop.Converter, errors, value) Then
' ReadValue succeeded. Fill in the property value.
'
Try
prop.SetValue(instance, value)
Catch ex As Exception
errors.Add(ex.Message)
End Try
End If
End If
End Sub
''' Generic function to read an object value. Returns true if the read
''' succeeded.
Private Function ReadValue(ByVal node As XmlNode, ByVal converter As TypeConverter, ByVal errors As ArrayList, <Out> ByRef value As Object) As Boolean
Try
For Each child As XmlNode In node.ChildNodes
If child.NodeType = XmlNodeType.Text Then
value = converter.ConvertFromInvariantString(node.InnerText)
Return True
ElseIf child.Name.Equals("Binary") Then
Dim data = Convert.FromBase64String(child.InnerText)
' Binary blob. Now, check to see if the type converter
' can convert it. If not, use serialization.
'
If GetConversionSupported(converter, GetType(Byte())) Then
value = converter.ConvertFrom(Nothing, CultureInfo.InvariantCulture, data)
Return True
Else
Dim formatter As BinaryFormatter = New BinaryFormatter()
Dim stream As MemoryStream = New MemoryStream(data)
value = formatter.Deserialize(stream)
Return True
End If
ElseIf child.Name.Equals("InstanceDescriptor") Then
value = ReadInstanceDescriptor(child, errors)
Return value IsNot Nothing
Else
errors.Add(String.Format("Unexpected element type {0}", child.Name))
value = Nothing
Return False
End If
Next
' If we get here, it is because there were no nodes. No nodes and no inner
' text is how we signify null.
'
value = Nothing
Return True
Catch ex As Exception
errors.Add(ex.Message)
value = Nothing
Return False
End Try
End Function
#End Region
#Region "Public methods"
''' This method writes out the contents of our designer in XML.
''' It writes out the contents of xmlDocument.
Public Function GetCode() As String
Flush()
Dim sw As StringWriter
sw = New StringWriter()
Dim xtw As XmlTextWriter = New XmlTextWriter(sw)
xtw.Formatting = Formatting.Indented
xmlDocument.WriteTo(xtw)
Dim cleanup As String = sw.ToString().Replace("<DOCUMENT_ELEMENT>", "")
cleanup = cleanup.Replace("</DOCUMENT_ELEMENT>", "")
sw.Close()
Return cleanup
End Function
Public Sub Save()
Save(False)
End Sub
''' <summary>
''' Save the current state of the loader. If the user loaded the file
''' or saved once before, then he doesn't need to select a file again.
''' Unless this is being called as a result of "Save As..." being clicked,
''' in which case forceFilePrompt will be true.
''' </summary>
Public Sub Save(ByVal forceFilePrompt As Boolean)
Try
Flush()
Dim filterIndex = 3
If Equals(fileName, Nothing) OrElse forceFilePrompt Then
Dim dlg As SaveFileDialog = New SaveFileDialog()
dlg.DefaultExt = "xml"
dlg.Filter = "XML Files|*.xml"
If dlg.ShowDialog() = DialogResult.OK Then
fileName = dlg.FileName
filterIndex = dlg.FilterIndex
End If
End If
If Not Equals(fileName, Nothing) Then
Select Case filterIndex
Case 1
' Write out our xmlDocument to a file.
Dim sw As StringWriter = New StringWriter()
Dim xtw As XmlTextWriter = New XmlTextWriter(sw)
xtw.Formatting = Formatting.Indented
xmlDocument.WriteTo(xtw)
' Get rid of our artificial super-root before we save out
' the XML.
'
Dim cleanup As String = sw.ToString().Replace("<DOCUMENT_ELEMENT>", "")
cleanup = cleanup.Replace("</DOCUMENT_ELEMENT>", "")
xtw.Close()
Dim file As StreamWriter = New StreamWriter(fileName)
file.Write(cleanup)
file.Close()
End Select
unsaved = False
End If
Catch ex As Exception
MessageBox.Show("Error during save: " & ex.ToString())
End Try
End Sub
#End Region
End Class ' class
End Namespace ' namespace |
ComponentModel .Design. IMenuCommandService
Répondre avec citation
Partager