I am getting error when I am compare two textbox values in C#

Question

0.00/5 (No votes)

See more:

Hello Guys! i am getting an error when i am compare two textbox values in c# \
the error is input string was not in correct format
please help me and tell me the solution

What I have tried:

C#

if (int.TryParse(textBox00.Text) > int.TryParse(txtTotal.Text))
                        {
                            MessageBox.Show("Amount is less than bill amount", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                            return;
                        }
                        else
                        {

Posted 19-Dec-16 12:32pm

Member 9983063

Updated 19-Dec-16 13:48pm

Add a Solution

Comments

cvogt61457 19-Dec-16 18:58pm

TryParse() returns a bool whether the value was successfully parsed. Not an integervalue.
To get the value, you need to provide a output variable or use int.Parse().
If you use int.Parse(), you will need to verify that the value does parse correctly.
I'm curious how you got this compile.

Philippe Mori 19-Dec-16 19:08pm

If you got that error, then you are probably using int.Parse and the input is not valid. Please post the real code you are using. Also, if you get an error, you should also indicate the content of the text boxes.

Another thing is that you should give your controls meaningful names. textBox00 is not very informative.

And given the fact that a text box could be empty or contain something that is not a number, you usually want to do the validation in multiple steps so that you can display the most appropriate error to the user.

2 solutions

Solution 2

Hi try this

C#

 int textBox00 = 0;
 int txtTotal = 0;

if(int.TryParse(textBox00.Text, out textBox00) && int.TryParse(txtTotal.Text,out txtTotal))
 {
     if (textBox00 > txtTotal)
     {
         MessageBox.Show("Amount is less than bill amount", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
         return;
     }else
     {

     }
 }else
 {
     //Conversion error
     MessageBox.Show("no valid number found", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);

 }

Posted 19-Dec-16 13:48pm

Jean-Claude ADIBA

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Mehedi Shams · Accepted Answer · 2016-12-19T13:23:00

Hi Member 9983063,

This is not the way TryParse() works. TryParse() requires two parameters - one is the text to convert to integer, and the second is the output variable where it stores the converted value. The code you provided translates into:

C#

if (Boolean > Boolean)     // You are trying to compare booleans.
{
    MessageBox.Show("Amount is less than bill amount", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    return;
}

This itself is wrong as a boolean can be compared with another boolean for '==' and '!=' only. Logically you cannot say 'if true is greater than false'. So this is one more compilation error along with the other compile error for TryParse().

You can try the following approach:

C#

int textBox00Val, txtTotalVal;
if (int.TryParse(textBox00.Text, out textBox00Val) == false)    // This line checks if there is an integer in the box, and also converts it to an integer.
{
    MessageBox.Show("textBox00 value must be anumber.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    return;
}

if (int.TryParse(txtTotal.Text, out txtTotalVal) == false)      // This line checks if there is an integer in the box, and also converts it to an integer.
{
    MessageBox.Show("txtTotal value must be anumber.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    return;
}

if (textBox00Val > txtTotalVal)     // Now you need to compare the integers.
{
    MessageBox.Show("Amount is less than bill amount", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    return;
}
............
............

What happens here is, you obtain the values in integers and then compare the integers.

@cvogt61457: I guess Member 9983063 meant a compile error, as the code in question will never compile (TryParse() must be provided two parameters, and a boolean cannot be compared to another boolean for 'greater than' operator).