c# - 需要实现 C# Counter

Question

我想制作增量和减量计数器。有两个按钮称为 X 和 Y。如果先按 X，然后按 Y，计数器应该增加。如果先按 Y 再按 X 计数器应该递减。

我对c#不熟悉。所以有人可以帮我吗？:(

Answer 1

听起来您需要 2 个变量：一个计数器和按下的最后一个按钮。我假设这是一个 WinForms 应用程序，因为您在我写这篇文章时没有指定。

class MyForm : Form
{
    // From the designer code:
    Button btnX;
    Button btnY;

    void InitializeComponent()
    {
        ...
        btnX.Clicked += btnX_Clicked;
        btnY.Clicked += btnY_Clicked;
        ...
    }

    Button btnLastPressed = null;
    int counter = 0;

    void btnX_Clicked(object source, EventArgs e)
    {
        if (btnLastPressed == btnY)
        {
            // button Y was pressed first, so decrement the counter
            --counter;
            // reset the state for the next button press
            btnLastPressed = null;
        }
        else
        {
            btnLastPressed = btnX;
        }
    }

    void btnY_Clicked(object source, EventArgs e)
    {
        if (btnLastPressed == btnX)
        {
            // button X was pressed first, so increment the counter
            ++counter;
            // reset the state for the next button press
            btnLastPressed = null;
        }
        else
        {
            btnLastPressed = btnY;
        }
    }
}

Answer 2

你会想要一个变量来跟踪计数器。

int counter = 0;

如果它是一个 Web 应用程序，那么您必须将其存储在某些位置，例如会话状态。然后在您的增量计数器按钮中：

counter++;

并在您的递减计数器按钮中执行以下操作：

counter--;

Answer 3

在另一个网站上找到了这个：

public partial class Form1 : Form
{
        //create a global private integer 
        private int number;

        public Form1()
        {
            InitializeComponent();
            //Intialize the variable to 0
            number = 0;
            //Probably a good idea to intialize the label to 0 as well
            numberLabel.Text = number.ToString();
        }
        private void Xbutton_Click(object sender, EventArgs e)
        {
            //On a X Button click increment the number
            number++;
            //Update the label. Convert the number to a string
            numberLabel.Text = number.ToString();
        }
        private void Ybutton_Click(object sender, EventArgs e)
        {
            //If number is less than or equal to 0 pop up a message box
            if (number <= 0)
            {
                MessageBox.Show("Cannot decrement anymore. Value will be  
                                                negative");
            }
            else
            {
                //decrement the number
                number--;
                numberLabel.Text = number.ToString();
            }
        }
    }