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No way of Invoking a generic method with multiple overload and out/byref parameters #641
Description
Environment
- Pythonnet version: 2.4.0.dev0
- Python version: 3.6.4
- Operating System: Windows 7 64
Details
-
Describe what you were trying to get done.
Invoke a generic method with multiple overload and out parameters
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What commands did you run to trigger this issue?
//C# SIDE
//...
public void GetProperty<T>(string propertyName, out T value){...} //<= The one i'm trying to get
public void GetProperty<T>(string propertyName, out T value, bool asRef){...}
public void GetProperty<T>(string propertyName, out T value, int index){...}
public void GetProperty<T>(string propertyName, out T value, int index, bool asRef){...}
public void GetProperty<T>(PropertyID propertyID, out T value, int index){...}
public void GetProperty<T>(PropertyID propertyID, out T value, bool asRef){...}
//...#PYTHON SIDE, What i've tested so far
object.GetProperty[System.Single]('PropertyName', None) #FAIL
object.GetProperty[System.Single]('PropertyName', System.Single(0).GetType()) #FAIL
object.GetProperty[System.Single]('PropertyName', System.Single(0).GetType().MakeByRefType()) #FAIL
object.GetProperty('PropertyName', None) #FAIL
object.GetProperty('PropertyName', System.Single(0).GetType()) #FAIL
object.GetProperty('PropertyName', System.Single(0).GetType().MakeByRefType()) #FAIL
object.GetProperty.Overloads[System.String, System.Single(0).GetType().MakeByRefType()]('PropertyName', None) #FAIL- Traceback:
Traceback (most recent call last):
File "C:\Users\{USER}\AppData\Local\Programs\Python\Python36\lib\runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "C:\Users\{USER}\AppData\Local\Programs\Python\Python36\lib\runpy.py", line 85, in _run_code
exec(code, run_globals)
File "D:/PythonWorkspace/{MODULE}\__main__.py", line 5, in <module>
test_pythonnet.launchTest()
File "D:/PythonWorkspace/{MODULE}\test_pythonnet.py", line 45, in launchTest
test = object.GetProperty[System.Single]('PropertyName', byref)
TypeError: No method matches given argumentsSo, i'm at a loss here, do i need to do all the reflection stuff by hand ?
Activity
den-run-ai commentedon Mar 5, 2018
@llezo you may want to have a look at this issue. I don't see any way to handle byref overloads reliably without re-writing the method resolution logic:
#265
RockHornetz commentedon Mar 5, 2018
That's what i thought.
I will try some hack on my side, because that sort of problem is everywhere on the DLLs i work with
Here is what i think i'll try:
What do you think?
den-run-ai commentedon Mar 5, 2018
@llezo i put something together here long ago, but be careful because in some edge cases this would pick the wrong overloaded method, e.g. when both byref and non-byref versions are present:
https://github.com/pythonnet/pythonnet/pull/227/files
RockHornetz commentedon Mar 5, 2018
Hmm it should do the trick but i'll keep an eye on what i'm calling.
Thanks !
williamsardar commentedon Apr 23, 2018
There is a more general issue here, that you can't choose a specific overload of a generic method. It always matches the first in MethodBinder.MatchParameters
public void GetProperty(string propertyName, T value){...} //<= The one i'm trying to get
public void GetProperty(double propertyName, T value){...}
Tobimaru commentedon Feb 24, 2019
Hi,
Is there any progress on resolving this issue? I have encountered a similar problem when trying out pythonnet with Infer.Net. So in my case I have on the C# side generic overloads that have signatures:
I'm trying to call the second overload in pythonnet as:
But when I check the type of
a, it givesVariable[System.Double[]]and notVariableArray[System.Double]. This makes sense since it's ambiguous without specifying the type of the output variable or specifying the type for the function. Since in python I can't pin the output variable to a specific type, I tried to resolve the ambiguity with:but then I get the exception:
It seems that there is pull-request (#227) ongoing, but it looks to have been work in progress for quite a while now. Is there someone working on resolving this issue? If not, is there a work-around that I could try?