genericundoredo.xml

从设计模式角度介绍了updo redo的实现方法

            Creates <see cref="T:GenericUndoRedo.UndoRedoHistory`1"/> with given capacity.
            </summary>
            <param name="subject"></param>
            <param name="capacity"></param>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.BeginCompoundDo">
            <summary>
            Begins a complex memento for grouping.
            </summary>
            <remarks>
            From the time this method is called till the time 
            <see cref="M:GenericUndoRedo.UndoRedoHistory`1.EndCompoundDo"/> is called, all the <i>DO</i> actions (by calling 
            <see cref="M:GenericUndoRedo.UndoRedoHistory`1.Do(GenericUndoRedo.IMemento{`0})"/>) are added into a temporary 
            <see cref="T:GenericUndoRedo.CompoundMemento`1"/> and this memnto will be pushed into the undo 
            stack when <see cref="M:GenericUndoRedo.UndoRedoHistory`1.EndCompoundDo"/> is called. 
            <br/>
            If this method is called, it's programmer's responsibility to call <see cref="M:GenericUndoRedo.UndoRedoHistory`1.EndCompoundDo"/>, 
            or else this history will be in incorrect state and stop functioning.
            <br/>
            Sample Code:
            <br/>
            <code>
            // Version 1: Without grouping
            UndoRedoHistory&lt;Foo&gt; history = new UndoRedoHistory&lt;Foo&gt;();
            history.Clear();
            history.Do(memento1);
            history.Do(memento2);
            history.Do(memento3);
            // history has 3 actions on its undo stack.
            
            // Version 1: With grouping
            history.BeginCompoundDo(); // starting grouping
            history.Do(memento1);
            history.Do(memento2);
            history.Do(memento3);
            hisotry.EndCompoundDo(); // must be called to finish grouping
            // history has only 1 action on its undo stack instead 3. 
            // This single undo action will undo all actions memorized by memento 1 to 3.
            </code>
            </remarks>
            <exception cref="T:System.InvalidOperationException">
            Thrown if previous grouping wasn't ended. See <see cref="M:GenericUndoRedo.UndoRedoHistory`1.EndCompoundDo"/>.
            </exception>
            <seealso cref="M:GenericUndoRedo.UndoRedoHistory`1.EndCompoundDo"/>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.EndCompoundDo">
            <summary>
            Ends grouping by pushing the complext memento created by <see cref="M:GenericUndoRedo.UndoRedoHistory`1.BeginCompoundDo"/> into the undo stack.
            </summary>
            <remarks>
            For details on how <i>grouping</i> works, see <see cref="M:GenericUndoRedo.UndoRedoHistory`1.BeginCompoundDo"/>.
            </remarks>
            <exception cref="T:System.InvalidOperationException">
            Thrown if grouping wasn't started. See <see cref="M:GenericUndoRedo.UndoRedoHistory`1.BeginCompoundDo"/>.
            </exception>/// <seealso cref="M:GenericUndoRedo.UndoRedoHistory`1.BeginCompoundDo"/>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.Do(GenericUndoRedo.IMemento{`0})">
            <summary>
            Pushes an memento into the undo stack, any time the state of <see cref="F:GenericUndoRedo.UndoRedoHistory`1.subject"/> changes. 
            </summary>
            <param name="m"></param>
            <remarks>
            This method MUST be properly involked by programmers right before (preferably) or right after 
            the state of <see cref="F:GenericUndoRedo.UndoRedoHistory`1.subject"/> is changed. 
            Whenever <see cref="M:GenericUndoRedo.UndoRedoHistory`1.Do(GenericUndoRedo.IMemento{`0})"/> is called, the status of <see cref="P:GenericUndoRedo.UndoRedoHistory`1.InUndoRedo"/> 
            should aways be checked first. See details at <see cref="P:GenericUndoRedo.UndoRedoHistory`1.InUndoRedo"/>. 
            This method causes redo stack to be cleared.
            </remarks>
            <seealso cref="P:GenericUndoRedo.UndoRedoHistory`1.InUndoRedo"/>
            <seealso cref="M:GenericUndoRedo.UndoRedoHistory`1.Undo"/>
            <seealso cref="M:GenericUndoRedo.UndoRedoHistory`1.Redo"/>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1._Do(GenericUndoRedo.IMemento{`0})">
            <summary>
            Internal <b>DO</b> action with no error checking
            </summary>
            <param name="m"></param>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.Undo">
            <summary>
            Restores the subject to the previous state on the undo stack, and stores the state before undoing to redo stack.
            Method <see cref="P:GenericUndoRedo.UndoRedoHistory`1.CanUndo"/> can be called before calling this method.
            </summary>
            <seealso cref="M:GenericUndoRedo.UndoRedoHistory`1.Redo"/>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.Redo">
            <summary>
            Restores the subject to the next state on the redo stack, and stores the state before redoing to undo stack. 
            Method <see cref="P:GenericUndoRedo.UndoRedoHistory`1.CanRedo"/> can be called before calling this method.
            </summary>
            <seealso cref="M:GenericUndoRedo.UndoRedoHistory`1.Undo"/>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.Clear">
            <summary>
            Clear the entire undo and redo stacks.
            </summary>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.PeekUndo">
            <summary>
            Gets, without removing, the top memento on the undo stack.
            </summary>
            <returns></returns>
        </member>
        <member name="M:GenericUndoRedo.UndoRedoHistory`1.PeekRedo">
            <summary>
            Gets, without removing, the top memento on the redo stack.
            </summary>
            <returns></returns>
        </member>
        <member name="P:GenericUndoRedo.UndoRedoHistory`1.InUndoRedo">
            <summary>
            Gets a value indicating if the history is in the process of undoing or redoing.
            </summary>
            <remarks>
            This property is extremely useful to prevent undesired "Do" being executed. 
            That could occur in the following scenario:
            event X causees a Do action and certain Undo / Redo action causes event X, 
            i.e. Undo / Redo causes a Do action, which will render history in a incorrect state.
            So whenever <see cref="M:GenericUndoRedo.UndoRedoHistory`1.Do(GenericUndoRedo.IMemento{`0})"/> is called, the status of <see cref="P:GenericUndoRedo.UndoRedoHistory`1.InUndoRedo"/> 
            should aways be checked first. Example:
            <code>
            void SomeEventHandler() 
            {
                if(!history.InUndoRedo) 
                    history.Do(...);
            }
            </code>
            </remarks>
        </member>
        <member name="P:GenericUndoRedo.UndoRedoHistory`1.UndoCount">
            <summary>
            Gets number of undo actions available
            </summary>
        </member>
        <member name="P:GenericUndoRedo.UndoRedoHistory`1.RedoCount">
            <summary>
            Gets number of redo actions available
            </summary>
        </member>
        <member name="P:GenericUndoRedo.UndoRedoHistory`1.SupportRedo">
            <summary>
            Gets or sets whether the history supports redo.
            </summary>
        </member>
        <member name="P:GenericUndoRedo.UndoRedoHistory`1.CanUndo">
            <summary>
            Checks if there are any stored state available on the undo stack.
            </summary>
        </member>
        <member name="P:GenericUndoRedo.UndoRedoHistory`1.CanRedo">
            <summary>
            Checks if there are any stored state available on the redo stack.
            </summary>
        </member>
    </members>
</doc>