C++/clrIntelliSense：沒有操作符「+」匹配這些操作數。系統：雙^ +系統：雙^

Question

String^name; 
Double^ math; 
Double^physics; 
Double^english; 
Double^chemistry; 
Double^cs; 
Double^avrg; 
Double^grade; 

name = this->name->Text; 
math = Convert::ToDouble(this->textmath->Text); 
physics = Convert::ToDouble(this->phis->Text); 
english = Convert::ToDouble(this->eng->Text); 
chemistry = Convert::ToDouble(this->chem->Text); 
cs = Convert::ToDouble(this->cstf->Text); 

Double^ sum = (math + physics + english + chemistry + cs)/5; 

在雙上一次的操作^總結出現的錯誤：
1智能感知：無操作員「+」匹配這些操作數 操作數類型是：系統：雙^ + System :: Double^ 你能幫我找到答案嗎？謝謝！

Answer 1

不要使用物體！

String^name = this->name->Text; 
Double math = Convert::ToDouble(this->textmath->Text); 
Double physics = Convert::ToDouble(this->phis->Text); 
Double english = Convert::ToDouble(this->eng->Text); 
Double chemistry = Convert::ToDouble(this->chem->Text); 
Double cs = Convert::ToDouble(this->cstf->Text); 

Double sum = (math + physics + english + chemistry + cs)/5.0;