How to convert integer to string and calculate result in texbox

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I have textbox and I wont to multiply the value in textbox and then use this textbox to show result in textbox_textChange()
the wiring Appears in x variable
here my code..

What I have tried:

private void textBox1_TextChanged(object sender, EventArgs e)
      {

          int x = int.Parse(textBox1.Text) * 350;

          textBox1.Text = x ;

      }

Posted 30-Jul-17 23:37pm

NebroProg

Updated 3-Feb-22 0:22am

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Karthik_Mahalingam · Answer 1 · 2017-07-30T23:45:00

Solution 1

textBox1.Text = x.ToString() ;

use Int32.ToString Method [^] or Convert.ToString Method [^]

Note: use Int32.TryParse Method [^] to avoid invalid format exception

Posted 30-Jul-17 23:45pm

Karthik_Mahalingam

Updated 30-Jul-17 23:47pm

v2

CPallini · Answer 2 · 2017-07-30T23:45:00

Solution 2

You should actually use two textboxes: the first reserved to user input and the second to computation output.

Posted 30-Jul-17 23:45pm

CPallini

Comments

NebroProg 31-Jul-17 6:56am

i tried it but not work

Jochen Arndt · Answer 3 · 2017-07-30T23:56:00

Solution 4

This can't be simply done using the TextChanged event because changing the content would raise the event again.

It is common to use another text box to show the result or provide a button to perform the calculation.

You should also use the Int32.TryParse Method (String, Int32) (System)[^] to handle invalid input.

If you still want to use the same box, you have to use a guarding variable:

bool selfUpdate = false;

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if (!selfUpdate)
    {
        int x;
        if (Int32.TryParse(textBox1.Text, out x))
        {
            x *= 350;
            selfUpdate = true;
            textBox1.Text = x.ToString();
            selfUpdate = false;
        }
    }
}

[EDIT]
But note that when using the above each change will update so that only single digits can be entered or text must be pasted.
[/EDIT]

Posted 30-Jul-17 23:56pm

Jochen Arndt

Updated 31-Jul-17 0:59am

v3

Comments

NebroProg 31-Jul-17 6:55am

error here if (int.TryParse(textBox1.Text, x))

Jochen Arndt 31-Jul-17 7:02am

See my updated answer.

The code was just to show how it can be done. It is an uncommon and not recommended solution.

NebroProg 31-Jul-17 7:25am

I tried to type any digit but the result is 0

Jochen Arndt 31-Jul-17 7:36am

I don't know what is happening because I can not run your code.

But you can use the debugger to set a break point on your function and inspect the variables. Or use the WriteLine() methods from the Debug or Trace classes to print them to the debug output window.

Richard MacCutchan 31-Jul-17 7:03am

The use of selfUpdate here is very clever; never occurred to me. :thumbsup:

Jochen Arndt 1-Aug-17 8:04am

Why should I try it?
I have not asked the initial question but provided a solution.

And that would not work when using within the TextChanged event handler because assigning a new value to the text box would fire the event again resulting in an infinite loop creating a stack overflow (as already explained in my answer).

Even when not calling that within the handler your code does not handle invalid inputs and throws exceptions which terminate the application when not catched.

So your code does not work without the above additional conditions and is not answering the initial question (besides using the ToString() method).

Finally, your code would not even compile!

radha patil 3-Aug-17 0:39am

sorry... instead of posting answer i replied you,that's what i removed the comment

SurangiTi · Answer 4 · 2017-07-30T23:50:00

Solution 3

Convert int to string before assign it to text-box Text property.

textBox1.Text=x.ToString();

refer this to learn

Convert.ToString Method.

Posted 30-Jul-17 23:50pm

SurangiTi

Comments

NebroProg 31-Jul-17 6:55am

this gives error

SurangiTi 31-Jul-17 7:31am

what's the error?

SurangiTi 31-Jul-17 7:48am

I think you are not clear of what you want to achieve.

I assume you want to multiply the integer written to the Textbox1. There are many ways to achieve this result based on the requirement.
Examples
--------

1)use a text box and a label. [single digits can be entered]
2)use a text box and a button. [this is the ideal solution]
3)there are many other ways...

Either way you need to validate user inputs, otherwise conversion errors will throw and it is not avoidable.

NebroProg · Answer 5 · 2017-07-31T02:42:00

Thank's alot my friends ^^
I try and try until I found the solution
I change the event of textbox from textBox1_textboxChange() totextBox1_KeyUp
and change code to

private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
int x = int.Parse(textBox1.Text) * 350;
textBox1.Text = Convert.ToString(x);
}

radha patil · Answer 6 · 2017-08-01T01:37:00

Solution 7

hi try this
double result=convert.double(textbox.text)*350;
textbox.text=result.tostring();

Posted 1-Aug-17 1:37am

radha patil