Windows phone:Do not allow more than one dot in a textbox?

Question

I am writing application in windows phone 8.

I need to provide a textbox which will allow user to enter only "Numbers" and if required, only one dot ".

I set <TextBox InputScope="Number" /> but it allow multiple dot.

How can i set single dot in textbox of windows phone?

Answer 1

Set an event that triggers everytime a text has change like this:

 <TextBox x:Name="textBox1" TextChanged="textBox1_TextChanged" />

And then in the event function loop through the text, count the dots and if the dot count is higher than 1, delete the said dot.

EDIT: you said if I could provide a sample algorithm:

        string str = textBox1.Text;
        int dotCount = 0;
        for (int i = 0; i < str.Length; i++)
        {
            if (str[i] == '.')
            {
                dotCount++;
                if (dotCount > 1)
                {
                    str.Remove(i, 1);
                    i--;
                    dotCount--;
                }
            }
        }