C#按钮循环？

发布时间：2020-12-16 01:56:40 所属栏目：百科来源：网络整理

导读：我正在试图找出一个我应该根据我的书写的代码(首先进入C#,3.5版).我完全被一个我想写的循环所困惑.这是我想要做的： Make a form,have a button,check box,and label. Only when the check box is marked,is the button suppose to change the background co

我正在试图找出一个我应该根据我的书写的代码(首先进入C#,3.5版).我完全被一个我想写的循环所困惑.这是我想要做的：

Make a form,have a button,check box,and label. Only when the check box is marked,is the button suppose to change the background color of the label. The color is suppose to switch between red and blue when the button is pressed.

这是我目前的代码.

namespace SecondColorChangingWindow
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender,EventArgs e)
        {
            while (checkBox1.Checked == false) // The code will stop if the box isn't checked
            {
                MessageBox.Show("You need the check box checked first!");
                break;//Stops the infinite loop
            }
            while (checkBox1.Checked == true)// The code continues "if" the box is checked.
            {
                bool isRed = false; // Makes "isRed" true,since the background color is default to red.

                if (isRed == true) // If the back ground color is red,this will change it to blue
                {
                    label1.BackColor = Color.Blue; // changes the background color to blue
                    isRed = false; //Makes "isRed" false so that the next time a check is made,it skips this while loop
                    MessageBox.Show("The color is blue.");//Stops the program so I can see the color change
                }
                if (isRed == false)//if the back ground color is blue,this will change it to red
                {
                    label1.BackColor = Color.Red;//Makes the background color red
                    isRed = true;//Sets the "isRed" to true
                    MessageBox.Show("The color is red.");//Stops the program so I can see the color change.
                }
            }
        }
    }
}

现在它只在红色上循环.我不明白我做错了什么.这不是我写的第一个代码.我已经从整数到布尔试图让颜色改变,但它要么：使颜色一次,而不是其他颜色.或者程序冻结,因为它无限循环.

解决方法

你不需要while循环,尝试条件并检查标签颜色如下

private void button1_Click(object sender,EventArgs e)
    {
        if(!checkBox1.Checked)
        {
            MessageBox.Show("You need the check box checked first!");
        }
        else
        {
            //changes the background color
            label1.BackColor = label1.BackColor == Color.Blue? Color.Red:Color.Blue;
            MessageBox.Show("The color is " + label1.BackColor.ToString());
        }
    }

如果checkBox1已选中,则在当前代码中没有中断条件.它将运行无限循环并冻结程序.你最好添加休息;在每个MessageBox.Show行之后.

（编辑：李大同）

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