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arrow_back What is Convert's error?

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1 vote
I don't understand the error, why the Convert function doesn't work.
Error at the bottom, when converting a

5f985a421a087955279643.png5f985ab299aeb856816914.png

#pragma once

namespace Project6 {

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>
/// Сводка для MyForm
/// </summary>
public ref class MyForm : public System::Windows::Forms::Form
{
public:
MyForm(void)
{
InitializeComponent();
//
//TODO: добавьте код конструктора
//
}

protected:
/// <summary>
/// Освободить все используемые ресурсы.
/// </summary>
~MyForm()
{
if (components)
{
delete components;
}
}
private: System::Windows::Forms::Label^ label1;
protected:
private: System::Windows::Forms::TextBox^ textBox1;
private: System::Windows::Forms::Label^ label2;
private: System::Windows::Forms::TextBox^ textBox2;
private: System::Windows::Forms::Label^ label3;
private: System::Windows::Forms::ComboBox^ comboBox1;
private: System::Windows::Forms::Button^ button1;
private: System::Windows::Forms::Button^ button2;
private: System::Windows::Forms::TextBox^ textBox3;

private:
/// <summary>
/// Обязательная переменная конструктора.
/// </summary>
System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
/// <summary>
/// Требуемый метод для поддержки конструктора — не изменяйте
/// содержимое этого метода с помощью редактора кода.
/// </summary>
void InitializeComponent(void)
{
this->label1 = (gcnew System::Windows::Forms::Label());
this->textBox1 = (gcnew System::Windows::Forms::TextBox());
this->label2 = (gcnew System::Windows::Forms::Label());
this->textBox2 = (gcnew System::Windows::Forms::TextBox());
this->label3 = (gcnew System::Windows::Forms::Label());
this->comboBox1 = (gcnew System::Windows::Forms::ComboBox());
this->button1 = (gcnew System::Windows::Forms::Button());
this->button2 = (gcnew System::Windows::Forms::Button());
this->textBox3 = (gcnew System::Windows::Forms::TextBox());
this->SuspendLayout();
//
// label1
//
this->label1->AutoSize = true;
this->label1->Font = (gcnew System::Drawing::Font(L"Microsoft Sans Serif", 12));
this->label1->Location = System::Drawing::Point(12, 43);
this->label1->Name = L"label1";
this->label1->Size = System::Drawing::Size(187, 20);
this->label1->TabIndex = 0;
this->label1->Text = L"Введите первое число:";
//
// textBox1
//
this->textBox1->Location = System::Drawing::Point(16, 77);
this->textBox1->Name = L"textBox1";
this->textBox1->Size = System::Drawing::Size(173, 20);
this->textBox1->TabIndex = 1;
//
// label2
//
this->label2->AutoSize = true;
this->label2->Font = (gcnew System::Drawing::Font(L"Microsoft Sans Serif", 12));
this->label2->Location = System::Drawing::Point(219, 43);
this->label2->Name = L"label2";
this->label2->Size = System::Drawing::Size(187, 20);
this->label2->TabIndex = 2;
this->label2->Text = L"Введите первое число:";
//
// textBox2
//
this->textBox2->Location = System::Drawing::Point(223, 77);
this->textBox2->Name = L"textBox2";
this->textBox2->Size = System::Drawing::Size(173, 20);
this->textBox2->TabIndex = 3;
//
// label3
//
this->label3->AutoSize = true;
this->label3->Font = (gcnew System::Drawing::Font(L"Microsoft Sans Serif", 12));
this->label3->Location = System::Drawing::Point(12, 119);
this->label3->Name = L"label3";
this->label3->Size = System::Drawing::Size(168, 20);
this->label3->TabIndex = 4;
this->label3->Text = L"Выберите операцию:";
//
// comboBox1
//
this->comboBox1->FormattingEnabled = true;
this->comboBox1->Items->AddRange(gcnew cli::array< System::Object^ >(4) { L"+", L"-", L"*", L"/" });
this->comboBox1->Location = System::Drawing::Point(16, 165);
this->comboBox1->Name = L"comboBox1";
this->comboBox1->Size = System::Drawing::Size(150, 21);
this->comboBox1->TabIndex = 5;
//
// button1
//
this->button1->Location = System::Drawing::Point(16, 260);
this->button1->Name = L"button1";
this->button1->Size = System::Drawing::Size(254, 69);
this->button1->TabIndex = 6;
this->button1->Text = L"Расчитать";
this->button1->UseVisualStyleBackColor = true;
this->button1->Click += gcnew System::EventHandler(this, &MyForm::button1_Click);
//
// button2
//
this->button2->Location = System::Drawing::Point(336, 260);
this->button2->Name = L"button2";
this->button2->Size = System::Drawing::Size(254, 69);
this->button2->TabIndex = 7;
this->button2->Text = L"Сбросить";
this->button2->UseVisualStyleBackColor = true;
//
// textBox3
//
this->textBox3->Location = System::Drawing::Point(31, 220);
this->textBox3->Name = L"textBox3";
this->textBox3->Size = System::Drawing::Size(436, 20);
this->textBox3->TabIndex = 8;
//
// MyForm
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(617, 445);
this->Controls->Add(this->textBox3);
this->Controls->Add(this->button2);
this->Controls->Add(this->button1);
this->Controls->Add(this->comboBox1);
this->Controls->Add(this->label3);
this->Controls->Add(this->textBox2);
this->Controls->Add(this->label2);
this->Controls->Add(this->textBox1);
this->Controls->Add(this->label1);
this->Name = L"MyForm";
this->Text = L"MyForm";
this->ResumeLayout(false);
this->PerformLayout();

}
<b>#pragma endregion
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {
double a, b;
a = Convert.ToDouble(textBox1->Text);
}
};
}

2 Answers

by
 
Best answer
0 votes
Convert::ToDouble
Ps. It's not c#
by
0 votes
Try replacing a = Convert.ToDouble(textBox1->Text); at a=double::Parse(textBox1->Text); because double.Parse
will return the number from its string representation.

2 Comments

5f985fcaddd89466571292.png
FlakeSunrise , And the variables double a, b; is used after assigning a value?