标签不会改变 [英] The label doesn't change
本文介绍了标签不会改变的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
I wrote a code in c# windows form application contain many if statement when I run project and enter data the label should change its color according to the if clause, but the color is still as in the last label
我尝试过:
What I have tried:
private void button1_Click(object sender, EventArgs e)
{
double height, weight;
double BMI = 0;
height = Convert.ToDouble(textBox1.Text);
weight = Convert.ToDouble(textBox2.Text);
BMI = weight / (height * height);
if (BMI < 18.5)
{
label3.Text = Convert.ToString("Under Weight");
label3.ForeColor = Color.Blue; }
else if
((BMI > 18.5) && (BMI < 24.9))
{ label3.Text = Convert.ToString("Normal");
label3.ForeColor = Color.Black;
}
else if ((BMI > 25) && (BMI < 29.9))
{ label3.Text = Convert.ToString("Over Weight");
label3.BackColor = System.Drawing.Color.Green;
label3.ForeColor = Color.White;
}
else if (BMI >= 30)
label3.Text = Convert.ToString("Obese");
label3.ForeColor = Color.Red;
}
推荐答案
我认为你的if条款与BMI值不符。
- BMI == 18.5
- 24.9< = BMI&& BMI< = 25
- 29.9< = BMI&& BMI< 30
以下代码将匹配任何BMI值。
I think your if clauses don't match below BMI value.
- BMI == 18.5
- 24.9 <= BMI && BMI <= 25
- 29.9 <= BMI && BMI < 30
Below code will be match any BMI value.
if (BMI < 18.5)
{
// Under Weight
}
else if (BMI < 25)
{
// Normal
}
else if (BMI < 30)
{
// Over Weight
}
else
{
// Obese
}
对于初学者,不要将Convert方法与用户输入一起使用 - 如果他们输入的值没有'如果匹配正确的格式,您的应用程序将崩溃。请改用TryParse方法:
For starters, don't use Convert methods with user input - if the value they enter doesn't match the right format, your application will crash. Use the TryParse methods instead:
double height, weight;
double BMI = 0;
if (!double.TryParse(textBox1.Text, out height))
{
MessageBox.Show(
\{ textBox1.Text} \不是有效的高度);
return ;
}
if (!double.TryParse(textBox2.Text, out weight) ))
{
MessageBox.Show(
"\"{textBox1.Text}\" is not a valid height"); return; } if (!double.TryParse(textBox2.Text, out weight)) { MessageBox.Show(
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