How To: Use .NET Framework Classes in Scripts

IronPython supports using .NET Framework classes from within scripts. This is extremely useful if you want to implement interfaces that import/export data from/to time cockpit.

Making .NET Classes Available

If you want to use .NET classes in a Python script you first have to add a reference to the DLL that contains the corresponding .NET classes. You can do that by calling clr.AddReference (for details about loading assemblies in IronPython see the corresponding chapter in the IronPython documentation).

After you have loaded the assemblies you have to import that namespaces using Python's import statement (for details about importing .NET namespaces in IronPython see the corresponding chapter in the IronPython documentation).

Advanced Topics

You can use advanced C# or .NET features like generics, nested types, etc. in Python, too. See IronPython's documentation for details.

Export Timesheets Into a Text File

The following example shows how to export timesheets into a text file:

clr.AddReference("mscorlib")
from System.IO import StreamWriter, File
from System import DateTime

timesheets = Context.SelectWithParams({
  "Query": "From T In Timesheet Where T.BeginTime >= @BeginTime And T.EndTime <= @EndTime Select T",
  "@BeginTime": DateTime(2010, 1, 1),
  "@EndTime": DateTime(2010, 1, 31) })

writer = StreamWriter("c:\\temp\\export.txt")
try:
  for timesheet in timesheets:
    writer.WriteLine(timesheet.BeginTime.ToString() + ";" 
      + timesheet.EndTime.ToString() + ";"
      + timesheet.Description)
finally:
  writer.Dispose()

print File.ReadAllText("c:\\temp\\export.txt")

print "Done!"

Import Countries From REST Service

The following example shows how to import countries from a REST service:

clr.AddReference("System")
from System.Net import WebRequest
from System.IO import StreamReader
from TimeCockpit.Data.QueryLanguage import QueryParameter

def download_text(url):
  req = WebRequest.Create(url)
  resp = req.GetResponse()
  try:
    respStream = resp.GetResponseStream()
    try:
      streamReader = StreamReader(respStream)
      return streamReader.ReadToEnd()
    finally:
      streamReader.Close()
  finally:
    respStream.Close()

countries = {}
content = download_text("http://download.geonames.org/export/dump/countryInfo.txt")
for line in content.splitlines():
  if not line.startswith("#"):
    columns = line.split("\t")
    countries[columns[0]] = {"IsoCode": columns[0], "EnglishName": columns[4], "Currency": columns[10], "Continent": columns[8], "GermanName": columns[4]}

for country in countries:
  germanCountryInfo = download_text("http://ws.geonames.org/countryInfoCSV?lang=de&country=%(countryIsoCode)s" % { "countryIsoCode": country })
  if len(germanCountryInfo) > 0:
    germanLines = germanCountryInfo.splitlines()
    if len(germanLines) >= 2:
      countries[country]["GermanName"] = germanLines[1].split("\t")[4]

  dbCountry = Context.SelectSingleWithParams({"Query": "From C In Country Where C.IsoCode = @IsoCode Select C", "@IsoCode": country})
  if dbCountry == None:
    dbCountry = Context.CreateCountry()
    dbCountry.IsoCode = country
  dbCountry.Name = countries[country]["EnglishName"]
  dbCountry.Currency = countries[country]["Currency"]
  dbCountry.GermanName = countries[country]["GermanName"]
  Context.SaveObject(dbCountry)

print "Done!"