c# NavisWorks ModelItem isReadOnly()始终为真

Question

我尝试在现有类别中为选定的NavisWorks模型项添加一些新属性

网络上的例子并不多，而且都是基于相同的COM方式。然而，在API中有特殊方法来添加可用的属性。唯一的问题是对象是锁定的。有没有办法解锁它？

    using ANA = Autodesk.Navisworks.Api;
...
    private void addProperty(string category, string prop, string value)
    {
        var oDoc = Autodesk.Navisworks.Api.Application.ActiveDocument;
        ModelItemCollection selectionModelItems = new ModelItemCollection();
        ANA.Application.ActiveDocument.CurrentSelection.SelectedItems.CopyTo(selectionModelItems);
        //Clear the current selection
        ANA.Application.ActiveDocument.CurrentSelection.Clear();
        try
        {
            foreach (ModelItem m in selectionModelItems)
            {
                foreach (PropertyCategory p in m.PropertyCategories)
                {
                    if (p.DisplayName != category) continue;
                    var property = new DataProperty(prop, prop, new VariantData(value));
                    p.Properties.Add(property);
                }
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

执行结果：

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Answer 1

Navisworks创建的特性和类别是只读的。您不能添加或修改由Navisworks创建的特性或类别。

您只能使用COM创建或添加用户定义的属性。请参见：

• https://adndevblog.typepad.com/aec/2012/05/create-attributes-and-properties-for-model-objects-using-net-api.html
• https://adndevblog.typepad.com/aec/2012/08/addmodifyremove-custom-attribute-using-com-api.html
• https://forums.autodesk.com/t5/navisworks-api/navisworks-api-add-user-data-tab/td-p/2916866

下面是一段代码片段(从上面提到的xiaodong.liang论坛帖子中复制)，它展示了如何使用COM添加用户定义的属性：

private void addProperty() {

  ComApi.InwOpState10 state;

  state = ComApiBridge.ComApiBridge.State;

  ModelItemCollection modelItemCollectionIn = new ModelItemCollection(Autodesk.Navisworks.Api.Application.ActiveDocument.CurrentSelection.SelectedItems);

  ComApi.InwOpSelection comSelectionOut =

    ComApiBridge.ComApiBridge.ToInwOpSelection(modelItemCollectionIn);

  ComApi.InwSelectionPathsColl oPaths = comSelectionOut.Paths();

  ComApi.InwOaPath3 oPath = (ComApi.InwOaPath3) oPaths.Last();

  ComApi.InwGUIPropertyNode2 propn = (ComApi.InwGUIPropertyNode2) state.GetGUIPropertyNode(oPath, true);

  ComApi.InwOaPropertyVec newPvec = (ComApi.InwOaPropertyVec) state.ObjectFactory(Autodesk.Navisworks.Api.Interop.ComApi.nwEObjectType.eObjectType_nwOaPropertyVec, null, null);

  ComApi.InwOaProperty newP = (ComApi.InwOaProperty) state.ObjectFactory(Autodesk.Navisworks.Api.Interop.ComApi.nwEObjectType.eObjectType_nwOaProperty, null, null);

  newP.name = "LXD_Property_Name";

  newP.UserName = "LXD_Property_UserName";

  newP.value = "LXD_Property_Value";

  newPvec.Properties().Add(newP);

  propn.SetUserDefined(0, "LXD_PropertyTab_Name", "LXD_PropertyTab_InteralName", newPvec);

}