generate pdf417 c# N-LEV EL UNDO in C#.NET

Generate PDF 417 in C#.NET N-LEV EL UNDO

CHAPTER 13 N-LEV EL UNDO
Printing PDF417 In C#.NET
Using Barcode creation for .NET framework Control to generate, create PDF-417 2d barcode image in .NET applications.
www.OnBarcode.com
PDF-417 2d Barcode Recognizer In C#
Using Barcode decoder for .NET framework Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
finally { _completelyRemoveChild = false; this.AllowRemove = oldAllowRemove; } } } // cancel edit on all deleted items for (int index = DeletedList.Count - 1; index >= 0; index--) { child = DeletedList[index]; child.UndoChanges(_editLevel, false); if (child.EditLevelAdded > _editLevel) { // if item is below its point of addition, remove DeletedList.RemoveAt(index); } else { // if item is no longer deleted move back to main list if (!child.IsDeleted) UnDeleteChild(child); } } } finally { this.RaiseListChangedEvents = oldRLCE; OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1)); } } First of all, _editLevel is decremented to indicate that one call to CopyState() has been countered. Notice that the loops going through the collection itself and the DeletedList collections go from bottom to top, using a numeric index value. This is important because it allows safe removal of items from each collection. Neither a foreach loop nor a forward-moving numeric index would allow removal of items from the collections without causing a runtime error. UndoChanges() is called on all child objects in the collection so that they can restore their individual states. After a child object s state is restored, the child object s edit level is checked to see when it was added to the collection. If the collection s new edit level is less than the edit level when the child object was added, it is a new child object that now must be discarded: // if item is below its point of addition, remove if (child.EditLevelAdded > _editLevel) { bool oldAllowRemove = this.AllowRemove; try { this.AllowRemove = true; _completelyRemoveChild = true; RemoveIndexItem(child); RemoveAt(index); }
Linear Generator In Visual C#
Using Barcode drawer for VS .NET Control to generate, create 1D Barcode image in .NET applications.
www.OnBarcode.com
Drawing Barcode In Visual C#.NET
Using Barcode printer for .NET Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
CHAPTER 13 N-LEV EL UNDO
PDF 417 Maker In Visual C#.NET
Using Barcode drawer for .NET Control to generate, create PDF-417 2d barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Encode Code 39 Full ASCII In C#.NET
Using Barcode maker for .NET Control to generate, create Code-39 image in .NET applications.
www.OnBarcode.com
finally { _completelyRemoveChild = false; this.AllowRemove = oldAllowRemove; } } The same process occurs for the objects in DeletedList; again, UndoChanges() is called on each child object. Then there s a check to see if the child object is a newly added object that can now be discarded: if (child.EditLevelAdded > _editLevel) { // if item is below its point of addition, remove DeletedList.RemoveAt(index); } A bit more work is required when dealing with the deleted child objects. It is possible that the undo operation needs to undelete an object. Remember that the IsDeleted flag is automatically maintained by UndoChanges(), so it is possible that the child object is no longer marked for deletion. In such a case, the object must be moved back into the active list: else { // if item is no longer deleted move back to main list if (!child.IsDeleted) UnDeleteChild(child); } At the end of the process, the collection object and all its child objects will be in the state they were when CopyState() was last called. Any changes, additions, or deletions will have been undone.
UPC A Creation In C#
Using Barcode printer for Visual Studio .NET Control to generate, create UPC Code image in .NET applications.
www.OnBarcode.com
ISSN Printer In C#.NET
Using Barcode creation for VS .NET Control to generate, create ISSN - 10 image in Visual Studio .NET applications.
www.OnBarcode.com
AcceptChanges
PDF 417 Scanner In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Generate PDF 417 In None
Using Barcode generation for Software Control to generate, create PDF417 image in Software applications.
www.OnBarcode.com
The AcceptChanges() method isn t nearly as complicated as UndoChanges(). It also decrements the _editLevel field to counter one call to CopyState(). The method then cascades the AcceptChanges() call to each child object so that each child object can accept its own changes. The only complex bit of code is that the edit level added value of each child must also be altered: void Core.IUndoableObject.AcceptChanges( int parentEditLevel, bool parentBindingEdit) { if (!parentBindingEdit) AcceptChanges(parentEditLevel); } private void AcceptChanges(int parentEditLevel) { if (this.EditLevel - 1 < parentEditLevel) throw new Core.UndoException( string.Format(Resources.EditLevelMismatchException, "AcceptChanges")); // we are coming up one edit level _editLevel -= 1; if (_editLevel < 0) _editLevel = 0;
Make Barcode In None
Using Barcode maker for Microsoft Excel Control to generate, create Barcode image in Microsoft Excel applications.
www.OnBarcode.com
Drawing GTIN - 12 In Visual Studio .NET
Using Barcode generator for .NET Control to generate, create UPC-A Supplement 5 image in .NET applications.
www.OnBarcode.com
CHAPTER 13 N-LEV EL UNDO
ANSI/AIM Code 39 Decoder In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Generating Linear 1D Barcode In Visual Basic .NET
Using Barcode encoder for .NET Control to generate, create Linear image in .NET applications.
www.OnBarcode.com
// cascade the call to all child objects foreach (C child in this) { child.AcceptChanges(_editLevel, false); // if item is below its point of addition, lower point of addition if (child.EditLevelAdded > _editLevel) child.EditLevelAdded = _editLevel; } // cascade the call to all deleted child objects for (int index = DeletedList.Count - 1; index >= 0; index--) { C child = DeletedList[index]; child.AcceptChanges(_editLevel, false); // if item is below its point of addition, remove if (child.EditLevelAdded > _editLevel) DeletedList.RemoveAt(index); } } While looping through the collection and DeleteList, the code makes sure that no child object maintains an EditLevelAdded value that s higher than the collection s new edit level. Think back to the LineItem example and suppose the collection is at edit level 1 and the changes are accepted. In this case, the newly added LineItem object is to be kept it s valid. Because of this, its EditLevelAdded property needs to be the same as the collection object, so it needs to be set to 0 as well. This is important because there s nothing to stop the user from starting a new edit session and raising the collection s edit level to 1 again. If the user then cancels the operation, the collection shouldn t remove the previous LineItem object accidentally. It was already accepted once, and it should stay accepted. This method won t remove any items from the collection as changes are accepted, so the simpler foreach looping structure can be used rather than the bottom-to-top numeric looping structure needed in the UndoChanges() method. When looping through the DeletedList collection, however, the bottom-to-top approach is still required. This is because DeletedList may contain child items newly added to the collection and then marked for deletion. Since they are new objects, they have no corresponding data in the database, so they can simply be dropped from the collection in memory. In such a case, those child objects are removed from the list based on their edit level value. This completes all the functionality needed to support n-level undo, allowing BusinessListBase to integrate with the code in the UndoableBase class.
Creating UCC - 12 In Java
Using Barcode creation for Android Control to generate, create GS1 128 image in Android applications.
www.OnBarcode.com
Paint PDF-417 2d Barcode In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create PDF-417 2d barcode image in Eclipse BIRT applications.
www.OnBarcode.com
PDF417 Creator In VS .NET
Using Barcode printer for ASP.NET Control to generate, create PDF-417 2d barcode image in ASP.NET applications.
www.OnBarcode.com
Barcode Creation In None
Using Barcode drawer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Creating Barcode In Java
Using Barcode drawer for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
Code 128 Code Set B Creation In Objective-C
Using Barcode maker for iPhone Control to generate, create USS Code 128 image in iPhone applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.