Converting a string to a number

Birger Sørensen

Parsing some XML-files to use in databses.
One of the data is a persons height.
In files it is given in feet - like 5.58.
Convert.ToDouble(), double.Parse() and double.TryParse() all return 558 - which is not correct.
I have tried with both single and double as the type - and the result is the same. Conversion pretents there is no decimal point.

Anybody has any idea, why this simple task is not possible in Visual Studio 2015?

9 Replies

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Rafnas T P9y ago
Accepted answer
what is the data type for Person.Height?
Birger Sørensen9y ago
Removed VS 2015 and installed VS 2017 instead.
Same problem (also can still not find tables in database, other than inside the IDE).

Inserted a test:
Person.Height = Double.Parse("5.58");
It still returns the number 558
If I write
Person.Height = 5.58;
everything is just fine; Person.Height IS = 5.58

So C sharp inside Viusal Studio appears to be C not very sharp...
Birger Sørensen9y ago
Yes.
I also could split the string at the . and calculate the value myself, as it seems C# can only convert strings to integers, and has a multitude of different build in functions, that are supposed to domething else, but does just that.
And I could invent a deep platter for my soup and hot water for my badth...

Sorry...
Rafnas T P9y ago
you can try decimal also
Birger Sørensen9y ago
Person.Height is currently type Double
Have tried float and Singe as well. Visual Studios version of C#, does not seem to accept float - it points to definition of type Single.
Which actually is why I decided on double, as float would/should be adequate.....
Birger Sørensen9y ago
example snippets from XML (3000 files, some with more than one instance)
5.58
5.41
5.84

I do like this:
Person.Height = double.Parse(ParseFileText("height", source, len));
// double.TryParse(ParseFileText("height", source, len), out Girl.Height);
// Person.Height = Convert.ToDouble(ParseFileText("height", source, len));
<= debugging Person.Height to the digits without the decimal point (558, 541, 584 ...)

@Rafnas - I have 3000+ that does this. So yes it does.
I am aware, it shouldn't - which doesn't mean that what IS happening doesn't.
Which in turn is why I ask here ....
(I did try again, after you saying it is not possible - but it still does not do as you tell it to)
Person is a struct, that also holds, name, age, address and other data.
weight and year of birth are otheres - these are integers, that come out right.

I use this function [debug version]:
private String ParseFileText(String param, String source, int len)
{
String ret = "";
int beg = source.IndexOf(param + ">", len) + 1 + param.Length;
int lgt = source.IndexOf(" if (lgt > 0) { ret = source.Substring(beg, lgt); }<= debugging, ret is "5.58", "5.41", "5.84" ...
return ret;
}

Non debug version looks like this:
private String ParseFileText(String param, String source, int len)
{
int beg = source.IndexOf(param + ">", len) + 1 + param.Length;
int lgt = source.IndexOf(" return (lgt > 0) ? source.Substring(beg, lgt) : "";
}
Which not surprisingly gives the exact same erroneous results in struct Person.
Rafnas T P9y ago
there is no way , you will be getting same output with decimal when you convert string with decimal places, please check your XML file what value exactly stored . it may be 558 not 5.58.
Vaibhav Deshmukh9y ago
Hi Birger,
If you try below code it definately gives you expected output.

double mySampleVariable1= Convert.ToDouble("5.58");//String to double

double mySampleVariable2= Convert.ToDouble(5.58f); //float to double
Nitin Sontakke9y ago
Could you please share the relevant portion of xml and piece of code you are using for the conversion?