Create CSV file from c#: extra character in excel
I create a CSV file from a C# application but the characters 
are displayed in Excel and OpenOfficeCalc in the first cell but not in Notepad and Notepad++.
Here is my code:
StreamWriter streamWriter = new StreamWriter(new FileStream(filePath, FileMode.Create), Encoding.UTF8);
List<MyData> myData = GetMyData;
foreach(MyData md in myData)
{
streamWriter.WriteLine(md.Date + "," + md.Data1 + "," + md.Data2 + "," + md.Data3 + "," + md.Data4);
}
streamWriter.Flush();
streamWriter.Close();
MyData
is
public struct MyData
{
public float Data1;
public float Data2;
public float Data3;
public float Data4;
public DateTime Date;
}
Here is the result in Notepad and Notepad++:
01/12/2010 00:04:00,0.08,78787.4,9.1,5
01/12/2010 00:09:00,0.07,78787.42,9.1,5
01/12/2010 00:14:00,0.06,78787.44,9.1,5
01/12/2010 00:19:00,1.45,78787.58,9.1,5
01/12/2010 00:24:00,2.13,78788.15,9.1,5
01/12/2010 00:29:00,1.72,78788.53,9,5
01/12/2010 00:34:00,0.89,78788.73,9,5
And in Excel and Calc:
01/12/2010 00:04:00 0.08 78787.4 9.1 5
01/12/10 00:09 0.07 78787.42 9.1 5
01/12/10 00:14 0.06 78787.44 9.1 5
01/12/10 00:19 开发者_运维问答1.45 78787.58 9.1 5
01/12/10 00:24 2.13 78788.15 9.1 5
01/12/10 00:29 1.72 78788.53 9 5
01/12/10 00:34 0.89 78788.73 9 5
Those 3 characters appears only once at the start of the file and then everything is as it should be.
My question is:
Where does 
come from and how to remove it?
I have tried to write my output in a StringBuilder and to debug to see its content and it does not have those character.
This is the BOM for UTF8 encoding
Look at this question: Write text files without Byte Order Mark (BOM)?
You may want to specify the encoding type based on your input. StreamWriter.Encoding Property
http://msdn.microsoft.com/en-us/library/system.io.streamwriter.encoding.aspx
I think that is BOM (unicode header). Specify ANSI encoding in constructor of StreamWriter. It is simple: Just set it to Encoding.Default
.
update:
If you must use UTF-8 and need to get rid of those 3 bytes at the beginning, use this: new UTF8Encoding(false)
. This way the writer will stay in UTF8, but won't write BOM.
Try to specify Encoding.ASCII
instead of using Encoding.UTF8
when you create the StreamWriter
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