1、命令管理器管理命令

void testCommandManagerArrangeCommand()
{
    cout<<">>>>>>>>>>>>命令管理器調(diào)度命令 <<<<<<<<<<<<"<<endl;
    CDeleteCommand *pCommand1=new CDeleteCommand("obj1");
    CDeleteCommand *pCommand2=new CDeleteCommand("obj2");
    CDeleteCommand *pCommand3=new CDeleteCommand("obj3");
    CDeleteCommand *pCommand4=new CDeleteCommand("obj4");

    CCommandManager manager;
    manager.Do(pCommand1);
    manager.Do(pCommand2);
    manager.Do(pCommand3);
    manager.Undo();
    manager.Undo();
    manager.Redo();
    manager.Undo();
    manager.Do(pCommand4);
    manager.Undo();
    manager.Redo();
}

執(zhí)行效果：

>>>>>>>>>>>>命令管理器調(diào)度命令<<<<<<<<<<<<
obj1 is deleted.
obj2 is deleted.
obj3 is deleted.
obj3 is undeleted.
obj2 is undeleted.
obj2 is deleted.
obj2 is undeleted.
obj4 is deleted.
obj4 is undeleted.
obj4 is deleted.

2、命令管理器管理命令管理器

//命令管理器調(diào)度命令管理器
void testCommandManagerArrangeCommandManager()
{
    cout<<">>>>>>>>>>>>命令管理器調(diào)度命令管理 器<<<<<<<<<<<<"<<endl;
    CDeleteCommand *pCommand1=new CDeleteCommand("cm1--obj1");
    CDeleteCommand *pCommand2=new CDeleteCommand("cm1--obj2");
    CDeleteCommand *pCommand3=new CDeleteCommand("cm1--obj3");
    CDeleteCommand *pCommand4=new CDeleteCommand("cm2--obj1");
    CDeleteCommand *pCommand5=new CDeleteCommand("cm2--obj2");
    CDeleteCommand *pCommand6=new CDeleteCommand("cm2--obj3");
    CCommandManager cm1;
    CCommandManager cm2;
    CCommandManager cmMain;
    cm1.SetParentCommandManager(&cmMain);
    cm2.SetParentCommandManager(&cmMain);
    cm1.Do(pCommand1);
    cm2.Do(pCommand4);
    cm1.Do(pCommand2);
    cm2.Do(pCommand5);
    cm1.Do(pCommand3);
    cm2.Do(pCommand6);
    cmMain.Undo();
    cmMain.Undo();
    cmMain.Undo();
    cmMain.Redo();
    cmMain.Undo();

}

執(zhí)行效果：

>>>>>>>>>>>>命令管理器調(diào)度命令管理器<<<<<<<<<<<<
cm1--obj1 is deleted.
cm2--obj1 is deleted.
cm1--obj2 is deleted.
cm2--obj2 is deleted.
cm1--obj3 is deleted.
cm2--obj3 is deleted.
cm2--obj3 is undeleted.
cm1--obj3 is undeleted.
cm2--obj2 is undeleted.
cm2--obj2 is deleted.
cm2--obj2 is undeleted.

注意：

1、確保命令的Execute和UnExecute是完全可逆的操作。

2、要保障Execute和UnExecute的可逆性，特別要關注他們執(zhí)行的環(huán)境（比如繪圖的時候，這些操作要有同樣的尺寸標準，否則很難實現(xiàn)互逆的操作）。

3、注意不要插入空命令。

代碼