PauseDrawing

汇总

使用 PauseDrawing 类暂停地图视图绘制，并在上下文管理器（ with 语句）中运行工具。

讨论

使用 PauseDrawing 类作为上下文管理器，暂停地图视图的绘制。 该类是一个上下文管理器，用于在对图层进行更新或运行地理处理工具时暂停地图视图的绘制。 地理处理工具的输出将被添加到 内容 窗格中，但在上下文管理器退出前不会绘制在地图视图中。 即使在 PauseDrawing 上下文管理器中调用 RefreshLayer 函数，地图视图也不会进行刷新，直到退出 with 块为止。

语法

PauseDrawing()

代码示例

PauseDrawing 示例 1

当使用更新游标应用更新时，可使用 PauseDrawing 类作为上下文管理器。

import arcpy
from random import randint

featureclass_1 = r"c:\data\myGDB.gdb\fc1"
featureclass_2 = r"c:\data\myGDB.gdb\fc2"

with arcpy.PauseDrawing():
    with arcpy.da.UpdateCursor(featureclass_1, "class_field") as cursor:
        for row in cursor:
            classification = randint(1, 5)
            row[0] = classification
            cursor.updateRow(row)

    with arcpy.da.UpdateCursor(featureclass_2, "class_field") as cursor:
        for row in cursor:
            classification = randint(1, 5)
            row[0] = classification
            cursor.updateRow(row)
    arcpy.RefreshLayer((featureclass_1, featureclass_2))

# The map view will refresh now that the PauseDrawing context manager has closed.

PauseDrawing 示例 2

当插入新要素并运行地理处理工具时，使用 PauseDrawing 类作为上下文管理器。

import arcpy
from random import randint

featureclass_1 = r"c:\data\myGDB.gdb\fc1"
featureclass_2 = r"c:\data\myGDB.gdb\fc2"

calculation_code_block = """
from random import randint
def f():
    return randint(1, 5)
"""

with arcpy.PauseDrawing():
    # Use cursors to copy geometries from one feature layer to another
    with arcpy.da.InsertCursor(featureclass_1, ["SHAPE@"]) as icur:
        with arcpy.da.SearchCursor(featureclass_2, "SHAPE@") as scur:
            for row in scur:
                icur.insertRow((row[0]))

    # Use CalculateField to update the class field
    arcpy.management.CalculateField(
        in_table=featureclass_1,
        field="class",
        expression="f()",
        expression_type="PYTHON3",
        code_block=calculation_code_block
        )

# The map view will refresh now that the PauseDrawing context manager has closed.