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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Actually it’s not related to the interfaces –
DataRow implements no interfaces! Instead what it has is a default member
which we of course map into __getitem__. And Python says that all things
with __getitem__ can be enumerated by going from 0 until you get an exception.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>In 2.0 we apparently support this conversion on user defined
types but not on built-in .NET types. I’m actually doing some work
now which will unify the .NET vs User-Defined type code paths so this will go
away but I’ve opened bug #17142 to track this (<a
href="http://www.codeplex.com/IronPython/WorkItem/View.aspx?WorkItemId=17142">http://www.codeplex.com/IronPython/WorkItem/View.aspx?WorkItemId=17142</a>).
That way afterwards we’ll make sure we’ve got a test in place and
it won’t regress in the future.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Now that being said you probably don’t actually want to be
doing this for performance reasons </span><span style='font-size:11.0pt;
font-family:Wingdings;color:#1F497D'>J</span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>. The way we know this
iteration is complete is when an exception is thrown which is going to be bad
for perf. Calling row.ItemArray is going to give you a real enumerable
object which terminates w/o an exception so you may see better perf that way - of
course that seems to make a copy of all the rows, so there’s a trade-off to
be made here…<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
users-bounces@lists.ironpython.com [mailto:users-bounces@lists.ironpython.com] <b>On
Behalf Of </b>Curt Hagenlocher<br>
<b>Sent:</b> Monday, June 23, 2008 8:37 AM<br>
<b>To:</b> Discussion of IronPython<br>
<b>Subject:</b> Re: [IronPython] DataRows and IronPython 2.0 B3<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>It's very unlikely that this was intentional. I
suspect that it's related to a change in the way we handle interfaces -- this
wouldn't be the first unanticipated consequence of that change. :/<o:p></o:p></p>
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<p class=MsoNormal><br>
<o:p></o:p></p>
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<p class=MsoNormal>On Mon, Jun 23, 2008 at 8:30 AM, Michael Foord <<a
href="mailto:fuzzyman@voidspace.org.uk">fuzzyman@voidspace.org.uk</a>>
wrote:<o:p></o:p></p>
<p class=MsoNormal>Note that we can fix it by iterating over 'row.ItemArray'
instead, I just wondered if the breakage was intentional.<br>
<span style='color:#888888'><br>
Michael Foord</span> <o:p></o:p></p>
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<p class=MsoNormal><br>
<br>
Michael Foord wrote:<o:p></o:p></p>
<p class=MsoNormal>Hello all,<br>
<br>
I'm further investigating potential compatibility issues with moving Resolver
One to IronPython 2, and I've encountered a change in behaviour with respect to
iterating over DataRows.<br>
<br>
The script below works in IronPython 1, printing all the data in the rows. In
IronPython 2.0 B3 it raises an exception.<br>
<br>
IronPython 1:<br>
C:\compile>c:\Binaries\ironpython\ipy.exe test_data.py<br>
0 System.Data.DataRow<br>
0 A Big Boy Did It and Ran Away<br>
1 System.Data.DataRow<br>
0 Affective Computing<br>
2 System.Data.DataRow<br>
0 Clear and Present Danger<br>
<br>
IronPython 2:<br>
C:\compile>c:\Binaries\ironpython2\ipy.exe test_data.py<br>
0 <System.Data.DataRow object at 0x000000000000002B
[System.Data.DataRow]><br>
Traceback (most recent call last):<br>
File "test_data.py", line 29, in test_data.py<br>
TypeError: expected IEnumerator, got DataRow<br>
<br>
<br>
Test script:<br>
<br>
import clr<br>
clr.AddReference('System.Data')<br>
<br>
from System.Data import DataSet<br>
from System.Data.Odbc import OdbcConnection, OdbcDataAdapter<br>
<br>
<br>
connectString = (<br>
"DRIVER={MySQL ODBC 3.51 Driver};"<br>
"blah blah blah"<br>
"OPTION=3;"<br>
)<br>
<br>
query = "SELECT title FROM books WHERE price > 2 ORDER BY title"<br>
<br>
connection = OdbcConnection(connectString)<br>
adaptor = OdbcDataAdapter(query, connection)<br>
dataSet = DataSet()<br>
connection.Open()<br>
adaptor.Fill(dataSet)<br>
connection.Close()<br>
<br>
for rowIndex, row in enumerate(dataSet.Tables[0].Rows):<br>
print rowIndex, row<br>
for colIndex, data in enumerate(row):<br>
print ' ', colIndex, data<br>
<br>
Michael Foord<br>
<a href="http://www.ironpythoninaction.com/" target="_blank">http://www.ironpythoninaction.com/</a><br>
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