.NET Framework - Double to String. Force the use of Dot

Asked By shapper

10-Feb-10 05:03 PM

Hello,

I am converting a double (4.2) to string and I get "4,0".
I would like to get always "4.0". With a dot instead of with a comma.

How can I do this? I am using ToString() ...
I can always use String.Replace but probably there might be a better
way or not?

Thanks,
Miguel

10-Feb-10 05:12 PM

hi,

Use a format provider:

http://msdn.microsoft.com/en-us/library/d8ztz0sa.aspx


mfG
--> stefan <--

10-Feb-10 05:19 PM

In particular, if you always want US-style strings even on
non-US-configured computers, passing CultureInfo.InvariantCulture as the
IFormatProvider is usually what you want to do.  For example:

double d = 4.2;
string str = d.ToString(CultureInfo.InvariantCulture);

Pete

10-Feb-10 05:18 PM

double x = 4.2;
x.ToString(CultureInfo.InvariantCulture.NumberFormat);

10-Feb-10 06:02 PM

CultureInfo implements IFormatProvider.  You do not need the

10-Feb-10 06:07 PM

I did try it by in the XML File I am creating I always get the comma
and not the not.

Here is my entire code:

MemoryStream stream =3D new MemoryStream();

// Define settings
var settings =3D new XmlWriterSettings {
Encoding =3D new UTF8Encoding(false),
ConformanceLevel =3D ConformanceLevel.Document,
Indent =3D true
};

// Open writer
XmlWriter writer =3D XmlWriter.Create(stream, settings);
writer.WriteStartElement("urlset", "http://www.sitemaps.org/
schemas/sitemap/0.9");
writer.WriteWhitespace(Environment.NewLine);

// Fill write
foreach (SitemapUrl u in Urls) {
writer.WriteStartElement("url");
writer.WriteElementString("loc", u.Location);
writer.WriteElementString("lastmod", u.Updated.ToString("yyyy-
MM-dd"));
writer.WriteElementString("changefreq",
u.ChangeFrequency.ToString().ToLower());
writer.WriteElementString("priority", String.Format("{0:0.0}",
(Double)u.Priority, CultureInfo.InvariantCulture));
writer.WriteEndElement();
writer.WriteWhitespace(Environment.NewLine);
}

// Close writer
writer.WriteWhitespace(Environment.NewLine);
writer.WriteEndElement();
writer.Flush();

// Define content
StringBuilder content =3D new StringBuilder();
content.Append(Encoding.UTF8.GetString(stream.ToArray()));
return content.ToString();

Check the priority ... I am trying to create string with only one
decimal from the double.
I get always the comma on the XML file.

If i just use a string "0.4" then it works fine ...

Any idea?

Thanks,
Miguel

10-Feb-10 06:16 PM

Sure.  You are not calling the method that all three of us have
suggested.  Instead, you are passing two objects to the String.Format()
method, only the first of which is ever even used (String.Format() has
no way to know you wanted to use the culture object passed in as a
format provider?as far as it knows, it is just another object to include
in the format, except your format string does not refer it).

Change this:

writer.WriteElementString("priority", String.Format("{0:0.0}",
(Double)u.Priority, CultureInfo.InvariantCulture));

To this:

writer.WriteElementString("priority",
((Double)u.Priority).ToString("0.0", CultureInfo.InvariantCulture));

Hope that helps.

Pete

10-Feb-10 07:23 PM

Thank You Pete! Once Again!

Cheers,
Miguel

10-Feb-10 08:38 PM

I would find it tempting to use the flavor:

writer.WriteElementString("priority",
String.Format(CultureInfo.InvariantCulture, "{0:0.0}", u.Priority));

Arne

10-Feb-10 11:58 PM

To each his own.  I see no real practical difference in this particular
case, and in other situations the call to String.Format() might require
boxing of a value type that otherwise would not have to happen if one
called ToString() directly.

But the code works fine either way.  :)