fix: try more options when failed to use netfx when import clr (#1791)

Author: HZBHZB1234

webview/platforms/edgechromium.py

@@ -6,7 +6,11 @@
 import winreg
 from threading import Semaphore
 
-import clr
+try:
+    import clr
+except Exception:
+    os.environ['PYTHONNET_RUNTIME'] = 'coreclr'
+    import clr
 
 from webview import Window, _state
 from webview import settings as webview_settings

webview/platforms/mshtml.py

@@ -5,7 +5,13 @@
 from ctypes import windll
 from threading import Semaphore
 
-import clr
+try:
+    import clr
+except Exception:
+    import os
+
+    os.environ['PYTHONNET_RUNTIME'] = 'coreclr'
+    import clr
 
 from webview import _state
 from webview.util import (

webview/platforms/winforms.py

@@ -10,7 +10,11 @@
 from platform import machine
 from threading import Event, Semaphore
 
-import clr
+try:
+    import clr
+except Exception:
+    os.environ['PYTHONNET_RUNTIME'] = 'coreclr'
+    import clr
 
 from webview import FileDialog, _state, settings, windows
 from webview.guilib import forced_gui_