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How do I make a richtextbox limited to only digits with a max number? (Cap)

Hey guys I wanted to make a richtextbox that only supports numbers and cant go above, 500 for example.
how would I go by doing that? thanks

I would use the keydown event to check if the pressed key is one of the keys you allow. With numbers it is pretty simple, maybe add ',' and '.' or other characters of your choice.

I'm not sure about the specifics but you can add something like
myRichTextBox.OnTextChanged() {
int number = 0;
bool checkInt = Int32.TryParse(myRichTextBox.Text, out number); //this checks if the value is int and stores as true or false, it stores the integer value in variable "number"
if ( checkInt = true && number > 500 ) //check if value in textbox is integer
{
myRichTextBox.Text = number.ToString();
}
else
{
DialogBox.Show("Please Enter Numbers Only");
myRichTextBox.Text = "";
}
}
You probably have to read the Int32.TryParse usage but brushing up this code should do what you want.
You can also put this code in a button onclick method to check that the value in textbox is integer before using the text.

C# - Restrict value entered to between 0.0 to 1.0 in a textbox

I am new to C# and WPF. I have a textbox in my WPF application and I want to limit the value entered by user in the textbox between 0.0 and 1.0. How do I do that?
Any help would be really helpful.

Something like this might work for you, as you will also get the value:
double valueEntered;
if (!double.TryParse(textBoxName.Text, out valueEntered)
// value is not a valid double
return;
else
if (valueEntered < 0 || valueEntered > 1)
// value is valid
return;
else
// value is not valid
return;
For a better implementation you should show us the XAML and the code-behind of your Window.

You can do the same with the help of Properties, if you are following MVVM
private double _MyLimittedValue;
public double MyLimittedValue
{
get { return _MyLimittedValue; }
set {
if (value < 0.0 || value > 1.0) { value = 0.0; }
_MyLimittedValue = value;
}
}
Then bind the MyLimittedValue to the Text of textbox with "mode=TwoWay,updatesourcetrigger=propertychanged".
So The text in the textbox becomes 0.0 in case you enter any other value.

This might do the trick for you
private void TexBoxName_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
var patten = #"^(0(\.\d*)?|1(\.0*)?)$";
Regex regex = new Regex(patten);
e.Handled = !regex.IsMatch(e.Text);
}

When you are using ranges. Try using RangeBase variants viz; ScrollBar, ProgressBar and Slider.
In your case Slider is the natural choice and would be best.

How to convert maskedtextbox value to int if it's empty?

I am building this C# windows application. On a certain Form, I am using maskedtextbox to enter upto 3 numerical digits, then I convert it into int as I have to send all these data to database with an insert query, but the problem is that these maskedtextboxes give error when left empty:
int scd_user_comm = Convert.ToInt32(maskedTextBox1.Text);
and the error is :
Input string was not in a correct format.
The corresponding field in database allows null, so if left empty, it must not give an error. Can anyone help please?
One side question:: Can I use a textbox or maskedtextbox to ensure that user only enters numeric value b/w 0 to 100? Thanks in advance.

You could try the Int32.TryParse() method
int scd_user_comm;
if(Int32.TryParse(maskedTextBox1.Text, out scd_user_comm) == false)
scd_user_comm = 0;
this will give you all the flexiblity required to work with your integer var and your maschedTextBox-
To force your maskTextBox to accept only numeric values set
maskTextBox1.Mask = "999";
maskTextBox1.TextMaskFormat = MaskFormat.ExludePromptAndLiterals;
However this is not enough to ensure the enterd number is between 0 and 100.
To get this result you need to use the Validating event and reject the input if is outside your limits
private void maskedTextBox1_Validating(object sender, CancelEventArgs e)
{
int num;
if (Int32.TryParse(maskedTextBox1.Text, out num) == true)
{
if (num < 0 || num > 100)
{
MessageBox.Show("Insert number between 0 and 100");
e.Cancel = true;
}
}
}

You could use the TryParse instead:
int scd_user_comm;
if(!Int32.TryParse(maskedTextBox1.Text, out scd_user_comm))
{
// Do something to notify the user that the text isn't a number.
}

price textbox double

I wondering of anyone can help. I have a homework and a questien in it i dont understand what i need to look for to figuer out how to find it.
This is what i need to look for
Convert the contents of the price TextBox to a double and
validate the converted value so it is >= 0.0.
Call the GetDouble method from the InputUtility class,
with min value 0 and max value some big number.
Use a const declaration for the max.value
this is what im going to get in to my if before im going to tell its true
can enter the code two
private bool ReadAndValidatePrice(out double price)
{
if
{
price = txtPrice.Text;
return true;
}
else
{
MessageBox.Show("Enter Numbers Only", "Invalid Character", MessageBoxButtons.OK, MessageBoxIcon.Error);
txtPrice.Focus();
return false;
What i fink im going to do is if it is 0.0 or bigger it going to type it out. im i going to do like 0.0 > 999999

This is the best I can do with the little information you are presenting. You don't have to declare a double and save the converted data to it, but it makes it easier to read.
double converted;
converted = Convert.ToDouble(priceTB.text)
// Check if the converted data and if is less than 0, return out of the method
if(converted >= 0.0)
return;

converting integer to decimal with precision value

how to make a text box to accept only decimal value with precision.
example.if the text box value is 12 .how to convert it to 12.00
and if it is 12.00 it must remain same..
thanks in advance.

You want to use a NumericUpDown-Control.
Edit: But to answer your question. To make TextBox-Control only accept numeric values, you'd have to suppress every key you do not want, and after that convert the input into a Decimal.
Decimal value = Convert.ToDecimal(this.yourTextBox.Text);
Or the fail-safe way:
Decimal value = 0;
String toParse = this.yourTextBox.Text;
if(!Decimal.TryParse(toParse, out value) {
// The user managed to break it...
}

A simple, fixed width variant is:
textBox1.Text = String.Format("{0,12:0.00}", textBox1.Text);
0 = first value (in this case
textBox1.Text)
12 = minimal width
0.00 = decimal (i.e. you could use #) find out more variants with
String.Format on msdn

Add an Event to the TextBoxChanged:
public void On_textbox1TextChanged(object sender, EventArgs e)
{
Double dblVal = 0;
if(Double.TryParse(this.textbox1.Text, ref dblVal))
{
this.textbox1.Text = dblVal.ToString("N2"); // Prints two 2 decimal places
}
else { /* Handle invalid value */ }
}

I would do a combination of the above on text change, and string formatting, but also go with a MASKED textbox. That will allow you to put in an expected mask to allow too.