文本框接受Windows Form C＃中的所有值

Question

I have wrote a program for arithmetic operations. Results are working fine. But I would like to go ahead a bit. I want a text box, that accepts all values like Positive, Negative Values, Decimal Values (Int, Float, Long, Double) excpet String or Character. While String or Character is entered, it should throw an error message (i will do it in Message box with try & Catch)

private void button1_Click(object sender, EventArgs e)
{
int num1, num2, res;
num1 = int.Parse(textBox1.Text);
num2 = int.Parse(textBox2.Text);
res = num1 * num2;
textBox3.Text = (num1 * num2).ToString();
}

Answer 1

Use TryParse , change num1 and num2 types for the most general one ( double ):

private void button1_Click(object sender, EventArgs e) {
  // double as the most general numeric type
  double num1, num2;

  if (!double.TryParse(textBox1.Text, out num1)) {
    if (textBox1.CanFocus) 
      textBox1.Focus();

    MessageBox.Show(String.Format("\"{0}\" is not a valid value", textBox1.Text));
  } 
  else if (!double.TryParse(textBox2.Text, out num2)) {
    if (textBox2.CanFocus) 
      textBox2.Focus();

    MessageBox.Show(String.Format("\"{0}\" is not a valid value", textBox2.Text));
  }
  else
    textBox3.Text = (num1 * num2).ToString();
}

Answer 2

You can use try catch, and use your variable as float so that you can free to input float and int data in textbox input

  private void button1_Click(object sender, EventArgs e)
  {
    float num1, num2, res;
    try
          {
             num1 = float.Parse(textBox1.Text);
          }
        catch (Exception)
          {
             MessageBox.Show("Error");       
          }
        try
          {
             num2 = float.Parse(textBox2.Text);
          }
        catch (Exception)
          {
             MessageBox.Show("Error");      
          }
    res = num1 * num2;
    textBox3.Text = (num1 * num2).ToString();
  }