Question

在输入数字后，我在某些textboxes内做了一些简单的计算。如果代码是单位数字，代码工作正常。但如果数字是两位数（例如10以上），则无法再次运行计算。

我不确定这是否是因为使用了TextChanged，但任何帮助都会很棒！

我的代码是：

private void textBox2_TextChanged(object sender, EventArgs e)
{
   if (textBox2.Text.Length == 0)
   {

   }
   else if (textBox4.Text.Length == 0)
   {
      percentage = Convert.ToDouble(textBox2.Text);
      percentage = double.Parse(textBox2.Text);
      percentage1 = percentage / 100;

      percentagecalc = percentage * total_loss;

      rate = percentagecalc / 0.5;
      rateString = System.Convert.ToString(rate);
      textBox4.Text = rateString;

      volume = rate * 0.5;
      volumeString = System.Convert.ToString(volume);
      textBox5.Text = volumeString;
   }
   if (textBox2.Text.Length == 0)
   {
      textBox4.Text = string.Empty;
      textBox5.Text = string.Empty;
   }                       
}

Answer 1

不是Length检查，而是TryParse：

private void textBox2_TextChanged(object sender, EventArgs e) {
  double p;

  if (double.TryParse(textBox2.Text, out p)) {
    // textBox2.Text has been changed and it contains double value - p
    percentage = p;

    percentage1 = percentage / 100;
    percentagecalc = percentage * total_loss;
    rate = percentagecalc / 0.5;

    rateString = System.Convert.ToString(rate);
    textBox4.Text = rateString;

    volume = rate * 0.5;
    volumeString = System.Convert.ToString(volume);
    textBox5.Text = volumeString;
  } 
  else {
    // textBox2.Text has been changed, but it can't be treated as double 
    // (it's empty or has some weird value like "bla-bla-bla")  
    textBox4.Text = string.Empty;
    textBox5.Text = string.Empty;
  }
}

不断更新文本框中的值c＃

1 个答案: