用c++实现NX二次开发线性尺寸的代码实现

以下是使用C++实现NX二次开发线性尺寸的代码示例：

#include <NXOpen/NXSession.hxx>
#include <NXOpen/Part.hxx>
#include <NXOpen/Annotations.hxx>
#include <NXOpen/Dimension.hxx>
#include <NXOpen/Expression.hxx>
#include <NXOpen/ExpressionCollection.hxx>
#include <NXOpen/Features_FeatureCollection.hxx>
#include <NXOpen/Features_DimensionFeature.hxx>
#include <NXOpen/Features_Feature.hxx>
#include <NXOpen/Features_FeatureManager.hxx>
#include <iostream>

using namespace NXOpen;

int main(int argc, char *argv[])
{
    // 初始化NXOpen会话
    NXOpen::Session::Initialize();
    Part *part = NXOpen::Session::Parts()->Create("SamplePart", "");
    NXOpen::Annotations::AnnotationManager *annoManager = part->Annotations();
    NXOpen::Annotations::DimensionAnnotation *dimAnno = NULL;

    try
    {
        // 创建线性尺寸
        dimAnno = annoManager->CreateDimension(Annotations::DimensionTypeLinear, Annotations::DimensionPreferenceTypeCreateNew);
        dimAnno->SetText("10mm");

        // 设置尺寸位置
        Point3d startPoint(0.0, 0.0, 0.0);
        Point3d endPoint(10.0, 10.0, 0.0);
        dimAnno->SetPosition(startPoint, endPoint);

        // 转换为表达式尺寸
        Features::FeatureManager *featManager = part->Features();
        Features::Feature *feat = featManager->CreateDimensionFeature(dimAnno);
        Features::DimensionFeature *dimFeat = dynamic_cast<Features::DimensionFeature *>(feat);
        ExpressionCollection *expCol = dimFeat->Expressions();
        Expression *exp = expCol->CreateExpression(dimAnno->GetDimensionText());

        // 修改表达式尺寸的值
        exp->SetValue(20.0);

        // 更新尺寸
        featManager->UpdateFeature(dimFeat);

        std::cout << "Linear dimension created and updated successfully." << std::endl;
    }
    catch (const std::exception &ex)
    {
        std::cerr << ex.what() << std::endl;
    }

    // 清理
    annoManager->DeleteObject(dimAnno);
    NXOpen::Session::Parts()->Delete(part);
    NXOpen::Session::Terminate();

    return 0;
}

在这个示例中，我们首先创建了一个新的零件，然后创建了一个线性尺寸，并将其设置在起点和终点之间。接下来，我们将线性尺寸转换为表达式尺寸，并使用表达式对象修改尺寸的值。最后，我们更新尺寸并清理对象。

请注意，这只是一个简单的示例，实际应用中可能需要更复杂的逻辑和错误处理。