C#实现简易计算器功能(2)(窗体应用)

前言

在上一篇教程C#实现简易计算器功能(1)中，我们使用控制台应用程序的方式实现了简易的计算器功能。但是，控制台程序的界面比较简陋，不够直观、美观。在这篇教程中，我们将使用Windows窗体应用程序的方式来实现简易计算器功能，界面将更加直观、友好。

步骤

1. 新建Windows窗体应用程序工程

打开Visual Studio，在主界面选择“创建新项目” -> “Windows桌面” -> “Windows窗体应用程序”，填写项目名称和路径，点击确定即可。

2. 构建用户界面

打开 Form1.cs 文件，我们可以看到自动生成的窗体界面。首先，我们需要设计计算器的用户界面。

本示例中的计算器界面由以下几个控件组成：

• 一个用于显示输入的文本框（textBox1）
• 数字键 0 到 9 的按钮（button0 到 button9）
• 加、减、乘、除运算符的按钮（buttonPlus，buttonMinus，buttonMul，buttonDiv）
• 小数点和清除键的按钮（buttonPoint和buttonClear）
• 等于号的按钮（buttonEqual）

在工具箱中，可以通过拖拽的方式将每个按钮控件添加到窗体中，然后设定对应的控件属性。

示例代码：

private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.Button button0;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.Button button3;
private System.Windows.Forms.Button button4;
private System.Windows.Forms.Button button5;
private System.Windows.Forms.Button button6;
private System.Windows.Forms.Button button7;
private System.Windows.Forms.Button button8;
private System.Windows.Forms.Button button9;
private System.Windows.Forms.Button buttonPlus;
private System.Windows.Forms.Button buttonMinus;
private System.Windows.Forms.Button buttonMul;
private System.Windows.Forms.Button buttonDiv;
private System.Windows.Forms.Button buttonEqual;
private System.Windows.Forms.Button buttonClear;
private System.Windows.Forms.Button buttonPoint;

private void InitializeComponent()
{
    this.textBox1 = new System.Windows.Forms.TextBox();
    this.button0 = new System.Windows.Forms.Button();
    this.button1 = new System.Windows.Forms.Button();
    this.button2 = new System.Windows.Forms.Button();
    this.button3 = new System.Windows.Forms.Button();
    this.button4 = new System.Windows.Forms.Button();
    this.button5 = new System.Windows.Forms.Button();
    this.button6 = new System.Windows.Forms.Button();
    this.button7 = new System.Windows.Forms.Button();
    this.button8 = new System.Windows.Forms.Button();
    this.button9 = new System.Windows.Forms.Button();
    this.buttonPlus = new System.Windows.Forms.Button();
    this.buttonMinus = new System.Windows.Forms.Button();
    this.buttonMul = new System.Windows.Forms.Button();
    this.buttonDiv = new System.Windows.Forms.Button();
    this.buttonEqual = new System.Windows.Forms.Button();
    this.buttonClear = new System.Windows.Forms.Button();
    this.buttonPoint = new System.Windows.Forms.Button();
    // textBox1
    this.textBox1.Font = new System.Drawing.Font("微软雅黑", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
    this.textBox1.Location = new System.Drawing.Point(12, 12);
    this.textBox1.Name = "textBox1";
    this.textBox1.ReadOnly = true;
    this.textBox1.Size = new System.Drawing.Size(291, 29);
    this.textBox1.TabIndex = 0;
    // button0
    this.button0.Font = new System.Drawing.Font("微软雅黑", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
    this.button0.Location = new System.Drawing.Point(12, 175);
    this.button0.Name = "button0";
    this.button0.Size = new System.Drawing.Size(64, 64);
    this.button0.TabIndex = 1;
    this.button0.Text = "0";
    this.button0.UseVisualStyleBackColor = true;
    // button1
    this.button1.Font = new System.Drawing.Font("微软雅黑", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
    this.button1.Location = new System.Drawing.Point(12, 105);
    this.button1.Name = "button1";
    this.button1.Size = new System.Drawing.Size(64, 64);
    this.button1.TabIndex = 2;
    this.button1.Text = "1";
    this.button1.UseVisualStyleBackColor = true;
    // 其他按钮略
    // Form1
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.ClientSize = new System.Drawing.Size(315, 372);
    this.Controls.Add(this.buttonPoint);
    this.Controls.Add(this.buttonClear);
    this.Controls.Add(this.buttonEqual);
    this.Controls.Add(this.buttonDiv);
    this.Controls.Add(this.buttonMul);
    this.Controls.Add(this.buttonMinus);
    this.Controls.Add(this.buttonPlus);
    this.Controls.Add(this.button9);
    this.Controls.Add(this.button8);
    this.Controls.Add(this.button7);
    this.Controls.Add(this.button6);
    this.Controls.Add(this.button5);
    this.Controls.Add(this.button4);
    this.Controls.Add(this.button3);
    this.Controls.Add(this.button2);
    this.Controls.Add(this.button1);
    this.Controls.Add(this.button0);
    this.Controls.Add(this.textBox1);
    this.Name = "Form1";
    this.Text = "简易计算器";
    this.ResumeLayout(false);
    this.PerformLayout();
}

3. 添加计算器逻辑代码

添加按钮的单击事件，编写逻辑代码实现计算器的功能。由于计算器的实现逻辑较为复杂，这里只给出示例代码，详细解释请参考上一篇教程。

示例代码：

public partial class Form1 : Form
{
    private string operation = "";
    private double num1 = 0.0, num2 = 0.0;
    private bool flag = false;

    public Form1()
    {
        InitializeComponent();
    }

    private void SetValue(string s)
    {
        if (flag == true)
        {
            textBox1.Text = "0";
            flag = false;
        }
        if (textBox1.Text == "0") textBox1.Text = "";
        textBox1.Text += s;
    }

    private void button0_Click(object sender, EventArgs e)
    {
        SetValue("0");
    }

    private void button1_Click(object sender, EventArgs e)
    {
        SetValue("1");
    }

    // 其他数字按钮略

    private void buttonPlus_Click(object sender, EventArgs e)
    {
        operation = "+";
        num1 = Convert.ToDouble(textBox1.Text.Trim());
        textBox1.Text = "0";
    }

    private void buttonMinus_Click(object sender, EventArgs e)
    {
        operation = "-";
        num1 = Convert.ToDouble(textBox1.Text.Trim());
        textBox1.Text = "0";
    }

    // 其他运算符按钮略

    private void buttonEqual_Click(object sender, EventArgs e)
    {
        if (operation == "+")
        {
            num2 = Convert.ToDouble(textBox1.Text.Trim());
            textBox1.Text = Convert.ToString(num1 + num2);
        }
        else if (operation == "-")
        {
            num2 = Convert.ToDouble(textBox1.Text.Trim());
            textBox1.Text = Convert.ToString(num1 - num2);
        }
        // 其他运算符逻辑略
        flag = true;
    }

    private void buttonClear_Click(object sender, EventArgs e)
    {
        textBox1.Text = "0";
        num1 = num2 = 0.0;
        flag = false;
    }

    private void buttonPoint_Click(object sender, EventArgs e)
    {
        if (flag == true)
        {
            textBox1.Text = "0";
            flag = false;
        }
        if (textBox1.Text.IndexOf('.') == -1)
        {
            textBox1.Text += ".";
        }
    }
}

编译并运行程序，可以看到一个简易的计算器界面，可以进行加、减、乘、除的计算。其中，点击清除键（C）可以清空输入和计算结果。