将值读入List对象

将值读入List对象 - 未将对象引用设置为对象的实例(Reading values into a List object - Object reference not set to an instance of an object)

尝试将值加载到List对象中，我得到“对象引用未设置为对象的实例”错误。

（编辑问题以简化它）

MyVec.h列表（仅限要点）：

ref class MyVec { public: List<double>^ MyVector; MyVec(void); };

MyVec.cpp列表（仅限要点）：

#include "MyVec.h" MyVec::MyVec(void) { }

Form.h列表（仅限要点）：

MyVec^ TestVec = gcnew MyVec(); double MyDouble = 1.002; TestVec->MyVector->Add(MyDouble); textBox1->Text = TestVec->MyVector[0].ToString() + "\r\n";

我在尝试将MyDouble分配给TestVec时遇到错误：TestVec-> MyVector-> Add（MyDouble）

在Autos窗口中，它表示（除其他外）TestVec-> MyVector未定义的值

怎么了？

Trying to load values into a List object, I get the "Object reference not set to an instance of an object" error.

(edited question to simplify it)

MyVec.h listing (essentials only):

ref class MyVec { public: List<double>^ MyVector; MyVec(void); };

MyVec.cpp listing (essentials only):

#include "MyVec.h" MyVec::MyVec(void) { }

Form.h listing (essentials only):

MyVec^ TestVec = gcnew MyVec(); double MyDouble = 1.002; TestVec->MyVector->Add(MyDouble); textBox1->Text = TestVec->MyVector[0].ToString() + "\r\n";

I get the error where I try to assign MyDouble to TestVec: TestVec->MyVector->Add(MyDouble)

In the Autos window it says (amongst other things) TestVec->MyVector undefined value

What's wrong?

最满意答案

这个改变应该解决问题：

MyVec::MyVec(void) { MyVector = gcnew List<double>(); }

类成员MyVector是initailly null引用。 您需要在使用之前初始化它，并且MyVec构造函数是适当的位置。

This change should solve the problem:

MyVec::MyVec(void) { MyVector = gcnew List<double>(); }

Class member MyVector is initailly null reference. You need to initialize it before using, and MyVec constructor is appropriate place to do it.