How to use data type float to calculate?

Question

1.00/5 (2 votes)

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I have a calculation I am trying to do with data type float. I have never done one before using float so i am new to this. This is the code I have so far:

C#

float c = float.Parse(TextBox1.Text.Replace(",", "").Replace(".", ""));
float d = float.Parse(TextBox2.Text.Replace(",", "").Replace(".", ""));
TextBox3.Text = (c-d).ToString();

It does the calculations for the result I get is wrong. It has numbers and letters in the textbox3.

This is what I am trying to calculate for each textbox. I am doing a subtraction.

C#

float c = float.Parse(TextBox1.Text.Replace(",", "").Replace(".", "")); //$46,534,798.18

float d = float.Parse(TextBox2.Text.Replace(",", "").Replace(".", "")); //$44,441,222.00

TextBox3.Text = (c-d).ToString(); //4.65348E+11

Please help me!!

What I have tried:

C#

float c = float.Parse(TextBox1.Text.Replace(",", "").Replace(".", ""));
float d = float.Parse(TextBox2.Text.Replace(",", "").Replace(".", ""));
TextBox3.Text = (c-d).ToString();

Posted 22-Jan-20 6:07am

Computer Wiz99

Updated 23-Jan-20 6:08am

v2

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Comments

Member 13566383 23-Jan-20 4:54am

Show us the content of your TextBox contents, the values of your variables c and d and the result contained in TextBox3.Text.
"The result is wrong" is not a meaningful error description.

Computer Wiz99 23-Jan-20 9:45am

Sorry about the long wait and the missing data. This is a subtraction calculation.

float c = float.Parse(TextBox1.Text.Replace(",", "").Replace(".", "")); //$46,534,798.18

float d = float.Parse(TextBox2.Text.Replace(",", "").Replace(".", "")); //$44,441,222.00

TextBox3.Text = (c-d).ToString(); //4.65348E+11

Richard MacCutchan 23-Jan-20 10:15am

Your text values include the $ sign which will cause the Parse call to fail.

Computer Wiz99 23-Jan-20 10:23am

I replace them and still get the same issue.
float c = float.Parse(TextBoxTBS1.Text.Replace(",", "").Replace(".", "").Replace("$", ""));
float d = float.Parse(TextBoxTBS2.Text.Replace(",", "").Replace(".", "").Replace("$", ""));

Richard MacCutchan 23-Jan-20 10:38am

Stop doing all these Relace calls, they are unnecessary. Use a Substring call to skip the $ sign:

float.Parse(TextBoxTBS1.Substring(1));

Better still use TryParse, as already suggested by phil.o below.

if (!float.TryParse(TextBoxTBS1.Substring(1), out c))
{
   // Handle here the case where a float value could not be properly parsed
}

Computer Wiz99 23-Jan-20 10:55am

So I am replacing my code with this:

float c, d;

if (!float.TryParse(TextBoxTBS1.Substring(1), out c))
{

}
if (!float.TryParse(TextBoxTBS2.Substring(1), out d))
{

}
but I have an error with TextBox1.Substring(1). I get the red line under it. So where does the subtraction take place?

Richard MacCutchan 23-Jan-20 11:37am

Sorry, that was my mistake, I forgot the Text property. It should be:

if (!float.TryParse(TextBoxTBS1.Text.Substring(1), out c))

2 solutions

Solution 1

You do not need/should not trim decimal and group separators from the strings you are trying to parse.
You should instead use Single.TryParse Method (System) | Microsoft Docs[^] , especially the overload which lets your specify the culture:

C#

float c, d;
NumberStyles styles = NumberStyles.Float | NumberStyles.AllowThousands;
if (!float.TryParse(TextBox1.Text, styles, CultureInfo.CurrentCulture, out c))
{
   // Handle here the case where a float value could not be properly parsed
}
if (!float.TryParse(TextBox2.Text, styles, CultureInfo.CurrentCulture, out d))
{
   // Handle here the case where a float value could not be properly parsed
}

If you remove decimal separator, there is a great chance that the value you will get will be incorrect (120.23 would become 12023, for example).

Posted 22-Jan-20 6:15am

phil.o

Updated 22-Jan-20 6:16am

v2

Comments

[no name] 23-Jan-20 13:15pm

What does it help to use CultureInfo.CurrentCulture from the server?

phil.o 23-Jan-20 13:23pm

Probably not much; but then the whole thing would be kind of useless since the content of the textboxes would need to be known on server side for it to work.

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Computer Wiz99 · Accepted Answer · 2020-01-23T06:09:00

Solution 2

This is what I did and it worked.

C#

decimal c;
c = 0;
c = decimal.Parse(SELTOTAL1.GetValue(0).ToString());

decimal d;
d = 0;
d = decimal.Parse(SELTOTAL2.GetValue(0).ToString());

decimal x = c - d;
TextBoxTBS3.Text = x.ToString();

Posted 23-Jan-20 6:09am

Computer Wiz99

Comments

Richard MacCutchan 23-Jan-20 12:17pm

1. Don't use Parse, use TryParse.
2. Why are you converting a value to a string just to convert it back to a value?