using System; using NXOpen; using NXOpen.Annotations; using NXOpen.UF;

namespace NXExpressionUpdate { class Program { static void Main(string[] args) { // 初始化NX环境 Session theSession = Session.GetSession(); UFSession theUFSession = UFSession.GetUFSession();

        try
        {
            // 打开指定部件文件
            string partPath = @"C:\Users\zhao.gang10\model.prt";
            PartLoadStatus partLoadStatus;
            Part workPart = theSession.Parts.OpenBaseDisplay(partPath, out partLoadStatus);

            // 切换到工作部件上下文
            theSession.Parts.SetWork(workPart);

            // 获取表达式集合
            Expression[] expressions = workPart.Expressions;

            // 查找并修改表达式
            bool found = false;
            foreach (Expression exp in expressions)
            {
                if (exp.Name == "a1")
                {
                    // 修改表达式值
                    exp.RightHandSide = "300";
                    found = true;
                    break;
                }
            }

            if (!found)
            {
                throw new Exception("未找到名为a1的表达式");
            }

            // 更新模型并保存
            workPart.Update();
            workPart.Save(Part.SaveComponents.True, Part.CloseAfterSave.False);

            Console.WriteLine("表达式a1已成功修改为300");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"操作失败: {ex.Message}");
        }
        finally
        {
            // 清理资源
            theSession.Dispose();
        }
    }
}

}