How to accept only numeric digits in C # Xamarin
I am new to C # with Xamarin. I am using Visual Studio for Mac Preview to work in an iOS app. While building a basic calculator, I cannot figure out how not to accept answers that are not a numerical digit. For example, in my text box, if I have pasted an email, I want to get the error
"Enter a numeric digit."
I don't know why I am getting the error, but not working.
When I run it and put in a number, it just references the else statement by default. Also with Letters. And when I place too many letters, it crashes.
partial void AddButton_TouchUpInside(UIButton sender)
{
double number1 = 0.00;
double answer = 0.00;
double number2 = 0.00;
int value;
string input = Console.ReadLine();
if (Int32.TryParse(input, out value))
{
number1 = double.Parse(Number1TextBox.Text);
number2 = double.Parse(Number2TextBox.Text);
answer = number1 + number2;
AnswerLabel.Text = "The answer is: " + answer.ToString();
}
else
{
InvalidLabel.Text = "Please enter a Numeric Digit";
}
}
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I think the problem is string input = Console.ReadLine();
Why are you expecting the correct value with this expression? This is applicable for a console program, but you are using an iOS app.
It will make sense:
string input = YourTextInput.Text;
If you want to restrict keyboard text input to numbers, use the following:
YourTextInput.KeyboardType = UIKeyboardType.NumberPad;
One more thing. If the answer should be double
, you should use double.TryParse(input, out value)
int instead.
How about this?
double number1 = 0.00;
double answer = 0.00;
double number2 = 0.00;
if (double.TryParse(Number1TextBox.Text, out number1)
&& double.TryParse(Number2TextBox.Text, out number2))
{
answer = number1 + number2;
AnswerLabel.Text = "The answer is: " + answer.ToString();
}
else
{
InvalidLabel.Text = "Please enter a Numeric Digit";
}
You still need to check the number entered as the numeric keypad allows you to enter more than one decimal point.
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I would recommend changing the TextBox so that the keyboard that appears is only numeric.
<Entry Keyboard="Numeric" />
Check out this Xamarin Guide for more information.
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Okay, I'm still a little confused. I've added all the code you said and when I enter a letter or two. The app just crashes with an error. So it still doesn't work. Also I tried to include under string input, .Text with the stuff you said and it just gave me a red line and won't work. Sorry, it just can't figure it out. Thanks to
Here's my code
partial void AddButton_TouchUpInside(UIButton sender)
{
double number1 = 0.00;
double answer = 0.00;
double number2 = 0.00;
string input = Number1TextBox.Text;
string inout = Number2TextBox.Text;
if (double.TryParse(Number1TextBox.Text, out number1)
&& double.TryParse(Number2TextBox.Text, out number2))
{
answer = number1 + number2;
AnswerLabel.Text = "The answer is: " + answer.ToString();
}
else
{
InvalidLabel.Text = "Please enter a Numeric Digit";
}
}
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