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恢复状态

2024-5-31 19:45| 发布者: admin| 查看: 10| 评论: 0|原作者: admin|来自: AutoCAD

恢复状态

如果指定了，则在调用 UNDO 命令时调用对象的函数。该函数是上的虚函数。派生类可以实现此函数，以解释撤消文件管理器存储的特定于类的信息并读取它。该函数必须确保类执行修改。如果不是，它必须是 super-message，如以下示例所示。kFalseautoUndoapplyPartialUndo()applyPartialUndo()AcDbObjectapplyPartialUndo()

如果要实现部分撤消机制，请务必调用以下函数，以便默认情况下不进行录制。

assertWriteEnabled(kFalse, kFalse);

举个例子，下面是 AsdkPoly 的函数：applyPartialUndo()

Acad::ErrorStatus 
AsdkPoly::applyPartialUndo(AcDbDwgFiler* filer,
                           AcRxClass* classObj)
{
    // The first thing to check is whether the class matches
    // ours. If it doesn't, we call the base class's
    // applyPartialUndo(); hopefully, one of them will
    // take care of it.
    //
    if (classObj != AsdkPoly::desc())
        return AcDbCurve::applyPartialUndo(filer, classObj);
    // Read the op-code and call the appropriate "set"
    // method to undo what was done. The "set" does the
    // filing again for redo.
    //
    Adesk::Int16 shortCode;
    filer->readItem(&shortCode);
    PolyOpCodeForPartialUndo code;
    code = (PolyOpCodeForPartialUndo)shortCode;
    Adesk::UInt32 value32;
    switch (code) {
    case kSetNumSides:
        filer->readItem(&value32);
        AOK(setNumSides(value32));
        break;
    default:
        assert(Adesk::kFalse);
        break;
    }
    return Acad::eOk;
}