所以我第一次在Windows Forms Applications中工作，我试图创建一个简单的计算器，但是在创建一个函数来检查边缘情况时，它不允许我调用该函数每当我运行程序。我用c ++创建了winform。这是我的代码。 isValidNumber（String s）是我试图调用的函数，我收到了一个错误。还附上了我的错误日志
#pragma once
namespace SimpleCalculator {
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;
/// <summary>
/// Summary for SimpleCalculator
/// </summary>
public ref class SimpleCalculator : public System::Windows::Forms::Form
{
public:
SimpleCalculator(void)
{
InitializeComponent();
//
//TODO: Add the constructor code here
//
}
protected:
/// <summary>
/// Clean up any resources being used.
/// </summary>
~SimpleCalculator()
{
if (components)
{
delete components;
}
}
private: System::Windows::Forms::TextBox^ numberTB1;
private: System::Windows::Forms::TextBox^ numberTB2;
private: System::Windows::Forms::ComboBox^ operationCB;
private: System::Windows::Forms::Label^ lblTotal;
private: System::Windows::Forms::Button^ btnCalculate;
protected:
protected:
private:
/// <summary>
/// Required designer variable.
/// </summary>
System::ComponentModel::Container ^components;
bool isValidNumber(String s);
#pragma region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
void InitializeComponent(void)
{
this->numberTB1 = (gcnew System::Windows::Forms::TextBox());
this->numberTB2 = (gcnew System::Windows::Forms::TextBox());
this->operationCB = (gcnew System::Windows::Forms::ComboBox());
this->lblTotal = (gcnew System::Windows::Forms::Label());
this->btnCalculate = (gcnew System::Windows::Forms::Button());
this->SuspendLayout();
//
// numberTB1
//
this->numberTB1->Location = System::Drawing::Point(23, 38);
this->numberTB1->Name = L"numberTB1";
this->numberTB1->Size = System::Drawing::Size(112, 20);
this->numberTB1->TabIndex = 0;
//
// numberTB2
//
this->numberTB2->Location = System::Drawing::Point(23, 64);
this->numberTB2->Name = L"numberTB2";
this->numberTB2->Size = System::Drawing::Size(111, 20);
this->numberTB2->TabIndex = 1;
//
// operationCB
//
this->operationCB->AccessibleDescription = L"";
this->operationCB->DropDownStyle = System::Windows::Forms::ComboBoxStyle::DropDownList;
this->operationCB->FormattingEnabled = true;
this->operationCB->Items->AddRange(gcnew cli::array< System::Object^ >(4) { L"Add", L"Subtract", L"Multiply", L"Divide" });
this->operationCB->Location = System::Drawing::Point(141, 49);
this->operationCB->Name = L"operationCB";
this->operationCB->Size = System::Drawing::Size(112, 21);
this->operationCB->TabIndex = 2;
//
// lblTotal
//
this->lblTotal->BackColor = System::Drawing::Color::White;
this->lblTotal->BorderStyle = System::Windows::Forms::BorderStyle::Fixed3D;
this->lblTotal->Font = (gcnew System::Drawing::Font(L"Microsoft Sans Serif", 20.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->lblTotal->Location = System::Drawing::Point(23, 105);
this->lblTotal->Name = L"lblTotal";
this->lblTotal->Size = System::Drawing::Size(229, 36);
this->lblTotal->TabIndex = 3;
this->lblTotal->Text = L"0";
//
// btnCalculate
//
this->btnCalculate->Font = (gcnew System::Drawing::Font(L"Microsoft Sans Serif", 20.25F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
static_cast<System::Byte>(0)));
this->btnCalculate->Location = System::Drawing::Point(23, 172);
this->btnCalculate->Name = L"btnCalculate";
this->btnCalculate->Size = System::Drawing::Size(229, 42);
this->btnCalculate->TabIndex = 4;
this->btnCalculate->Text = L"Calculate";
this->btnCalculate->UseVisualStyleBackColor = true;
this->btnCalculate->Click += gcnew System::EventHandler(this, &SimpleCalculator::btnCalculate_Click);
//
// SimpleCalculator
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(284, 261);
this->Controls->Add(this->btnCalculate);
this->Controls->Add(this->lblTotal);
this->Controls->Add(this->operationCB);
this->Controls->Add(this->numberTB2);
this->Controls->Add(this->numberTB1);
this->Name = L"SimpleCalculator";
this->Text = L"SimpleCalculator";
this->ResumeLayout(false);
this->PerformLayout();
}
#pragma endregion
double firstNum;
double secondNum;
double total;
private: System::Void btnCalculate_Click(System::Object^ sender, System::EventArgs^ e) {
if (SimpleCalculator::isValidNumber(numberTB1->ToString) == false || SimpleCalculator::isValidNumber(numberTB2->ToString) == false){
MessageBox::Show("Input valid Number in TextBox", "Invalid Number Input", MessageBoxButtons::OK, MessageBoxIcon::Error);
}
else if (operationCB->ToString == ""){
MessageBox::Show("Input valid Operation in Dropdown", "Invalid Operation Input", MessageBoxButtons::OK, MessageBoxIcon::Error);
}
else if (operationCB->ToString == "Divide" && Convert::ToDouble(numberTB2->Text) == 0){
MessageBox::Show("Invalid Division Operation. Cannot Divide by 0", "0 Division Operation", MessageBoxButtons::OK, MessageBoxIcon::Error);
}
else{
firstNum = Convert::ToDouble(numberTB1->Text);
secondNum = Convert::ToDouble(numberTB2->Text);
if ((this->operationCB)->Text == "Add"){
total = firstNum + secondNum;
lblTotal->Text = Convert::ToString(total);
}
else if ((this->operationCB)->Text == "Subtract"){
total = firstNum - secondNum;
lblTotal->Text = Convert::ToString(total);
}
else if ((this->operationCB)->Text == "Multiply"){
total = firstNum * secondNum;
lblTotal->Text = Convert::ToString(total);
}
else {
total = firstNum / secondNum;
lblTotal->Text = Convert::ToString(total);
}
}
}
};
bool isValidNumber(String s){
bool validDecimal = true;
if ((s.Length == 1 && s[0] == '.') || s.Length == 0){
return false;
}
int i = 0;
while (i < s.Length){
if (s[i].IsDigit || (s[i] == '.' && validDecimal == true)){
if (s[i] == '.')
validDecimal = false;
}
else{
return false;
}
}
return true;
}
}
错误2错误C3867：＆＃39; System :: Windows :: Forms :: TextBoxBase :: ToString＆＃39;：函数调用缺少参数列表;使用＆＃39;＆amp; System :: Windows :: Forms :: TextBoxBase :: ToString＆＃39;创建指向成员的指针c：\ users \ user \ documents \ visual studio 2013 \ projects \ simplecalculator \ simplecalculator \ SimpleCalculator.h 142 1 SimpleCalculator
答案 0 :(得分：0)
实际上问题不是与WinForms相关，而是相当琐碎的错误。有几个地方缺少ToString个括号（ToString是一个方法）。
你可以通过添加括号来轻松修复它，它会编译，但很可能你会得到一个错误的结果。您真正需要做的是用相应的属性访问器->ToString替换->Text（主要用于调试目的）。
您应该做的另一件事是制作isValidNumber方法static，因为它没有使用任何州。
static bool isValidNumber(String s){
// ...
}