Validate Textboxes And I Have Value In Double Data Type

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I have a two text boxes and i want to take amount and person from user and divide amount/person and convert result into double
here is my code but it will give me error, Here is my code and below is the erro code

C#

protected void btnSearch_Click(object sender, EventArgs e)
{
if((txtAmount.Text == "") || (txtPerson.Text == ""))
{
Response.Write("please enter amount");
} 
else
{
double amount = int.Parse(txtAmount.Text);
double persons = int.Parse(txtPerson.Text);
double result = amount / persons;
d.Price = Convert.ToInt32(result);
d.Select(d);
Display();
}

C#

Line 39:             else
Line 40:             {
Line 41:                 double amount = int.Parse(txtAmount.Text);
Line 42:                 double persons = int.Parse(txtPerson.Text);
Line 43:                 double result = amount / persons;

Posted 16-Feb-14 20:45pm

Ali Ashiq

Updated 16-Feb-14 20:46pm

Gitanjali Singh

v2

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3 solutions

Solution 1

Repalce

C#

double amount = int.Parse(txtAmount.Text);
double persons = int.Parse(txtPerson.Text);

With

C#

double amount = Double.Parse(txtAmount.Text);
double persons = Double.Parse(txtPerson.Text);

This may help.

Posted 16-Feb-14 20:49pm

Gitanjali Singh

Updated 16-Feb-14 21:22pm

v4

Comments

Ali Ashiq 17-Feb-14 2:58am

still not working it will give error on this line
double amount = int.TryParse(txtAmount.Text);

Gitanjali Singh 17-Feb-14 3:01am

check updated solution.

Ali Ashiq 17-Feb-14 3:06am

double amount = Double.TryParse(txtAmount.Text);
still giving error :(

Gitanjali Singh 17-Feb-14 3:14am

Debug and check the value of textbox txtAmount.What error you are getting?

Gitanjali Singh 17-Feb-14 3:22am

Please Check updated solution.This is working fine on my end.

Ali Ashiq 17-Feb-14 3:33am

No overload for method TryParse takes 1 arguments this error begins

Gitanjali Singh 17-Feb-14 3:35am

Use Parse instead of TryParse.
double amount = Double.Parse(txtAmount.Text);
double persons = Double.Parse(txtPerson.Text);

Ali Ashiq 17-Feb-14 3:47am

its woeking now but the error message is comming on the top of the page not under that text box and when i run my application 1st time it will show error on this line
Line 41: double amount = Double.Parse(txtAmount.Text);

Exception Details: System.FormatException: Input string was not in a correct format.

Gitanjali Singh 17-Feb-14 4:10am

Try this.
double amount = double.Parse(txtAmount.Text);
double persons = double.Parse(txtPerson.Text);
Refer:http://stackoverflow.com/questions/19049906/input-string-was-not-in-a-correct-format-in-double-parse

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wmdroshan · Accepted Answer · 2014-02-16T21:57:00

I think your code does not validate input values properly.

C#

if((txtAmount.Text == "") || (txtPerson.Text == ""))
{
    Response.Write("please enter amount");
}

is only for "" or String.Empty. What about " " (one space)?

And what about invalid values (NaN - not a number values)? You should modify this code to validate them and give proper error messages.

txtAmount.Text.Trim() is a good call (for the other text box as well) to cut down spaces.

Also, use TryParse() to validate against NaN and non-double values. It returns false if the validation fails.

Ex :-

C#

double amount;

if (double.TryParse(txtAmount.Text, out amount))

wmdroshan · Accepted Answer · 2014-02-16T22:25:00

Solution 3

OK. Please try this.

C#

string amountText = txtAmount.Text;
string personsText = txtPerson.Text;

double amount;
double persons;

if (double.TryParse(amountText.Trim(), out amount) && double.TryParse(personsText.Trim(), out persons))
{
    //both amountText and personsText are valid.
    double result = amount / persons;
}
else
{
    //something is invalid. show some error.
}

Posted 16-Feb-14 22:25pm

wmdroshan

Comments

Ali Ashiq 17-Feb-14 4:47am

All working perfectly sir but a minor problem is occured is that error message is begin/show on the top of the page, didn't show message near and under that text box

Ali Ashiq 17-Feb-14 4:48am

Thank you so much sir i shall be very thankful to you for that kind act...

wmdroshan 17-Feb-14 4:53am

Please kind enough to mark right solutions as answered. Thanks.

Ali Ashiq 17-Feb-14 4:57am

ok i will going to mark as answered please tell me how could error message is set under the textbox

wmdroshan 17-Feb-14 5:03am

What do you mean by "set under the textbox" ? Simply show it under the text box? This depends on the technology you use (WinForms, WPF, etc...) Normally there are Validators. Check this out as a start point, http://msdn.microsoft.com/en-us/library/ms229603%28v=vs.110%29.aspx