Developer should not use "Hide extensions for known file types" in Windows Explorer

One my colleague got a new PC and had a problem opening file using simple code(just from MSDN example ):
 
FileInfo fi1 = new FileInfo(relativePath);

        if (!fi1.Exists)
....
It showed that file doesn't exist. We've tried also File.Exists(relativePath), changed the path to absolule- the same result-
file is visible in Windows Explorer, but doesn't exist in code. Note that directory was shown in debugger as existing.
We've created(using Windows Explorer) a new Text file, named "test.txt" and tried to open it in code- the same "file not exist" problem.
We've checked different security settings- the same.
Finally I recognized, that  Windows Explorer was set to "Hide extensions for known file types" and file visible as "test.txt" was actually created as
test.txt.txt.
The lesson: developer (and any user who has understanding of file extensions) should never have "Hide extensions for known file types" in Windows Explorer.
By the way: If you want to use a relative path from Windows Service, reset current directory  in the code
System.IO.Directory.SetCurrentDirectory (System.AppDomain.CurrentDomain.BaseDirectory);

Convert DataSet and DataTable to Xml String helper functions

I created 2 helper functions(can be modified as extensions in .Net Framework 3.5) to output/trace content of DataSet  or DataTable
public static string ToStringAsXml(DataSet ds)

{

 StringWriter sw = new StringWriter();
ds.WriteXml(sw, XmlWriteMode.IgnoreSchema);

string s = sw.ToString();

return s;

}
 

public static string ToStringAsXml(DataTable dt)
{
 StringWriter sw = new StringWriter();
dt.WriteXml(sw, XmlWriteMode.IgnoreSchema);
string s = sw.ToString();
return s;

}

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