在c#应用程序中选择不同的转换

我有一个转换长度的c#应用程序。如果用户输入一个以点（3.45）分隔的数字，应用程序会工作并给出正确的结果，但如果用户输入逗号（3,45），则会给出错误的结果。有人知道我如何解决这个问题吗

    private void butCal_Click(object sender, EventArgs e)
    {
        // initialising and declaring variables 

        double miles, kilometres, feet, metres, inches, centimetres = 0;

        // the if statements initiates an event handler to select items from the conversions (combobox) to do conversion

        if (Conversions.Text == "Miles to Kilometres")
        {
            if (!double.TryParse(txtNumber.Text, out miles)) // verifies that the string entered is a number
            {
                MessageBox.Show("Please enter a number !"); // displays message if no number is entered
            }

            // Logic for doing calculations
            kilometres = miles * 1.6093; 
            txtAnswer.Text = kilometres.ToString("N2") + " Kilometres"; // displays the answer and rounds it off to two decimals

            txtAnswer.Visible = true;
            txtAnswer.Enabled = false;
            lblAnswer.Text = " Answer = ";
            lblAnswer.Visible = true;
        }

        else if (Conversions.Text == "Kilometres to Miles")
        {
            if (!double.TryParse(txtNumber.Text, out kilometres))
            {
                MessageBox.Show("Please enter a number.");
            }
            miles = kilometres * 0.621;
            txtAnswer.Text = miles.ToString("N2") + " miles ";

            txtAnswer.Visible = true;
            txtAnswer.Enabled = false;
            lblAnswer.Text = " Answer = ";
            lblAnswer.Visible = true;
        }
        else if (Conversions.Text == "Feet to Metres")
        {
            if (!double.TryParse(txtNumber.Text, out feet))
            {
                MessageBox.Show("Please enter a number.");
            }
            metres = feet * 0.3048;
            txtAnswer.Text = metres.ToString("N2") + " metres ";

            txtAnswer.Visible = true;
            txtAnswer.Enabled = false;
            lblAnswer.Text = " Answer = ";
            lblAnswer.Visible = true;
        }

        else if (Conversions.Text == "Metres to Feet")
        {
            if (!double.TryParse(txtNumber.Text, out metres))
            {
                MessageBox.Show("Please enter a number.");
            }
            feet = metres * 3.280839895;
            txtAnswer.Text = feet.ToString("N2") + " Ft ";

            txtAnswer.Visible = true;
            txtAnswer.Enabled = false;
            lblAnswer.Text = " Answer = ";
            lblAnswer.Visible = true;
        }

        else if (Conversions.Text == "Inches to Centimetres")
        {
            if (!double.TryParse(txtNumber.Text, out inches))
            {
                MessageBox.Show("Please enter a number.");
            }
            centimetres = inches * 2.54;
            txtAnswer.Text = centimetres.ToString("N2") + " cm ";
        }

        else if (Conversions.Text == "Centimeters to Inches")
        {
            if (!double.TryParse(txtNumber.Text, out centimetres))
            {
                MessageBox.Show("Please enter a number.");
            }
            inches = centimetres * 0.3937;
            txtAnswer.Text = inches.ToString("N2") + " Inches ";

            txtAnswer.Visible = true;
            txtAnswer.Enabled = false;
            lblAnswer.Text = " Answer = ";
            lblAnswer.Visible = true;
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        // resetting all labels, text fields and the conversion (combobox)
        Conversions.SelectedIndex = -1;
        txtNumber.Clear();
        txtAnswer.Clear();
        butCal.Visible = false;

        // Hidding text fields and labels until they are called
        txtAnswer.Visible = false;
        txtNumber.Visible = false;
        lblAnswer.Visible = false;
        lblNumber.Visible = false;
    }

    private void butExit_Click(object sender, EventArgs e)
    {
        Close(); // exits the application
    }

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double.TryParse有一个重载，用于获取区域性或数字样式

---

特别是对于

IFormatProvider提供程序

参数，如果您特别提到（3,45），可以对点使用CultureInfo.InvariantCulture，因为3,45可能没有任何意义。如果你想让它工作，请使用@selman22提供的解决方案，否则如果你确认用户输入的输入将是标准之一，即，将用于分离千，则使用此处给出的解决方案，类似于double或@Softlion提供的解决方案，考虑到你的要求。你可以试试下面的方法

   try
{
    double.Parse(txtNumber.Text, CultureInfo.InvariantCulture)
}
catch(Exception ae)
 {
            MessageBox.Show("Not a Number")
 }

---

你不能在开头用

替换

，

。请详细说明错误RESULT@NitinVarpe-不，因为

3100

并不意味着

3.100

，它的意思是

3100

（或者其他方式，取决于您的居住地）…如果输入类似的内容

1,23.3

：）？为什么还要麻烦呢？所有问题的答案都是42，所以

text=“42”

保证了正确的解析和可靠的结果。这是一个特例：D然后我们需要进行一些额外的验证，但OP没有问到。这里的问题是

3,45

仍然被认为是一个有效的数字。根据用户的区域设置，它将被（错误地）解释为

3.45

或

345

。那么什么时候抛出错误呢？

   try
{
    double.Parse(txtNumber.Text, CultureInfo.InvariantCulture)
}
catch(Exception ae)
 {
            MessageBox.Show("Not a Number")
 }