Question

你在按钮事件中有一个if语句，当我运行代码并选择第一个收音机并单击按钮（进行计算）时，它会在标签上打印出来，但是当我点击时第二个单选按钮，然后单击按钮来计算答案根本没有任何反应。有任何想法

 private void button1_Click(object sender, EventArgs e)
     {
          if (radioButton1.Checked == true)
             {
                 double a;  // have to declare double here as we cannot include it below as bool is a rue or false statment

                 bool success1 = double.TryParse(textBox1.Text, out a); // take in value as true or false

                 if (success1) // check if it was parsed successful
                 {
                     label4.Text = ConvertToCel(a).ToString(); // now set it in label
                 }
                 else if (radioButton1.Checked == false && radioButton2.Checked == true)
                 {
                     double a1;

                     bool success = double.TryParse(textBox1.Text, out a1);

                     if (success){
                         label3.Text = ConvertToFar(a1).ToString();
                     }
                 }
                 else if (radioButton1.Checked == false && radioButton2.Checked == false)
                 {
                     label4.Text = "Please select an option from above";
                 }
             }
         }�

Answer 1

问题是您正在检查首先检查radiobutton1的条件，然后在其中嵌套其他条件，因此如果第一个条件为false，则不检查其他条件，以避免您应该带另一个否则if条件超出第一个if条件，你可以使用： -

private void button1_Click(object sender, EventArgs e)
{
    double a;  // have to declare double here as we cannot include it below as bool is a rue or false statment

    bool success1 = double.TryParse(textBox1.Text, out a); // take in value as true or false

    if (radioButton1.Checked == true)
    {
        if (success1) // check if it was parsed successful
        {
            label4.Text = ConvertToCel(a).ToString(); // now set it in label
        }
    }
    else if (radioButton1.Checked == false && radioButton2.Checked == true)
    {
        if (success)
        {
            label3.Text = ConvertToFar(a).ToString();
        }
    }
    else if (radioButton1.Checked == false && radioButton2.Checked == false)
    {
        label4.Text = "Please select an option from above";
    }
}

Answer 2

这是因为单选按钮是互斥的，如果选中radioButton1，则只执行代码。您可能还应该处理无法正确解析文本框的情况（即，如果用户输入的内容无法转换为double）。我已将其包括在内。

double a;
bool success = double.TryParse(textBox1.Text, out a);

if (success)
{
    if (radioButton1.Checked == true)
    {
        label4.Text = ConvertToCel(a).ToString();
    }
    else if (radioButton2.Checked == true)
    {
        label3.Text = ConvertToFar(a).ToString();
    }
    else
    {
        label4.Text = "Please select an option from above";
    }
}
else
{
    label4.Text = "The value could not be convered to a number.";
}

Answer 3

那是因为您已将else放在第一个if语句中的if语句中。只有当第一个if语句中的条件为真时，才会运行对radiobutton 2的检查。

在if语句之前结束第一个else语句的块：

private void button1_Click(object sender, EventArgs e)
{
    if (radioButton1.Checked == true)
    {
        double a;  // have to declare double here as we cannot include it below as bool is a rue or false statment

        bool success1 = double.TryParse(textBox1.Text, out a); // take in value as true or false

        if (success1) // check if it was parsed successful
        {
            label4.Text = ConvertToCel(a).ToString(); // now set it in label
        }
    }
    else if (radioButton1.Checked == false && radioButton2.Checked == true)
    {
        double a1;

        bool success = double.TryParse(textBox1.Text, out a1);

        if (success){
            label3.Text = ConvertToFar(a1).ToString();
        }
    }
    else if (radioButton1.Checked == false && radioButton2.Checked == false)
    {
        label4.Text = "Please select an option from above";
    }
}

嵌套if和normal if语句

3 个答案: