AttributeError when modifying vector layer symbology with PyQGIS

Question

In QGIS 3.22 I'm facing a problem with QgsMapLayer. I want to use it on QGIS in order to modify the symbology of line, point & polygon in each layer but every time it gives me an error on using the library of PyQGIS.

This is the script I'm using:

from PyQt5.QtGui import *
from qgis.core import * 

lyr = QgsVectorLayer("PATH", 'ligne', 'ogr')
QgsProject.instance().addMapLayer(lyr)
sym = QgsLineSymbol.createSimple({'Line_style': 'dash', 'Color': 'red'})
symbol = lyr.QgsMapLayer.createMapRenderer().symbols(QgsRenderContext())
sym = symbols[0]
lyr.triggerRepaint()

And here is the error message:

AttributeError: 'QgsVectorLayer' object has no attribute 'QgsMapLayer'

Is there is any solution for that?

Answer 1

I don't fully understand what you are trying to do but try this:

lyr = QgsVectorLayer("PATH", 'ligne', 'ogr')
QgsProject.instance().addMapLayer(lyr)

sym = QgsLineSymbol.createSimple({'line_style':'dash', 'color':'red'})
lyr.renderer().setSymbol(sym)
lyr.triggerRepaint()

line_style and color are case-sensitive. Don't use Line_style and Color.