练习 - 使用 Concurrent 函数测试性能

已完成

可通过本实操练习探索如何使用 Concurrent 函数来增强性能。

1. 登录 Power Apps。

2. 从主屏幕左侧的导航菜单中依次选择 +创建 > 空白应用 > 创建（从空白画布应用下）。

3. 使用适当的标题为您的应用命名，然后选择创建。

4. 首先，我们来构建两个集合，但不 使用 Concurrent 函数。 插入按钮控件，命名为 btnCollection，将其 Text 属性设置为 "Collection"，将其 OnSelect 属性设置为此公式：

   Set(varStart,Now());
   ClearCollect(colFruit,
   {Name: "banana", Category: "fruit",AvgCost: .49},
   {Name: "peach", Category: "fruit",AvgCost: 1.12},
   {Name: "strawberry", Category: "fruit",AvgCost: 2.99},
   {Name: "apple", Category: "fruit",AvgCost: 0.98},
   {Name: "orange", Category: "fruit",AvgCost: 1.49},
   {Name: "pear", Category: "fruit",AvgCost: 0.97},
   {Name: "cantaloupe", Category: "fruit",AvgCost: 3.99},
   {Name: "pineapple", Category: "fruit",AvgCost: 2.49},
   {Name: "cherry", Category: "fruit",AvgCost: 4.99},
   {Name: "mango", Category: "fruit",AvgCost: .99}
   );
   ClearCollect(colVegetable,
   {Name: "carrot", Category: "vegetable",AvgCost: .95},
   {Name: "lettuce", Category: "vegetable",AvgCost: 1.69},
   {Name: "potato", Category: "vegetable",AvgCost: 5.14},
   {Name: "zuccini", Category: "vegetable",AvgCost: 1.99},
   {Name: "broccoli", Category: "vegetable",AvgCost: 1.49},
   {Name: "cabbage", Category: "vegetable",AvgCost: 2.48},
   {Name: "celery", Category: "vegetable",AvgCost: 1.65},
   {Name: "asparagus", Category: "vegetable",AvgCost: 2.99},
   {Name: "kale", Category: "vegetable",AvgCost: 1.99},
   {Name: "cauliflower", Category: "vegetable",AvgCost: 3.24});
   Set(varSpeedCollect, Text(DateDiff(varStart, Now(), TimeUnit.Milliseconds)));
   

5. 插入一个文本标签，将其 BorderThickness 属性设为 3，将其重命名为 lblSpeedCollect，然后将其 Text 属性设为：

   varSpeedCollect
   

6. 按住 Alt 键并选择 Collection 按钮。 txtSpeedCollect 标签会以毫秒为单位显示运行流程所用的时间。

   

7. 现在，我们在应用中添加 Concurrent 功能，并比较性能。 插入另一按钮控件，命名为 btnConcurrent，将其 Text 属性设为“Concurrent”，将其 OnSelect 属性设为此公式：

   Set(varStart,Now());
   Concurrent(
   ClearCollect(collectFruit,
   {Name: "banana", Category: "fruit",AvgCost: .49},
   {Name: "peach", Category: "fruit",AvgCost: 1.12},
   {Name: "strawberry", Category: "fruit",AvgCost: 2.99},
   {Name: "apple", Category: "fruit",AvgCost: 0.98},
   {Name: "orange", Category: "fruit",AvgCost: 1.49},
   {Name: "pear", Category: "fruit",AvgCost: 0.97},
   {Name: "cantaloupe", Category: "fruit",AvgCost: 3.99},
   {Name: "pineapple", Category: "fruit",AvgCost: 2.49},
   {Name: "cherry", Category: "fruit",AvgCost: 4.99},
   {Name: "mango", Category: "fruit",AvgCost: .99}
   ),
   ClearCollect(collectVegetable,
   {Name: "carrot", Category: "vegetable",AvgCost: .95},
   {Name: "lettuce", Category: "vegetable",AvgCost: 1.69},
   {Name: "potato", Category: "vegetable",AvgCost: 5.14},
   {Name: "zucchini", Category: "vegetable",AvgCost: 1.99},
   {Name: "broccoli", Category: "vegetable",AvgCost: 1.49},
   {Name: "cabbage", Category: "vegetable",AvgCost: 2.48},
   {Name: "celery", Category: "vegetable",AvgCost: 1.65},
   {Name: "asparagus", Category: "vegetable",AvgCost: 2.99},
   {Name: "kale", Category: "vegetable",AvgCost: 1.99},
   {Name: "cauliflower", Category: "vegetable",AvgCost: 3.24}));
   Set(varSpeedConcurrent, Text(DateDiff(varStart, Now(), TimeUnit.Milliseconds)));
   

8. 插入另一文本标签，将其 BorderThickness 属性设为 3，重命名为 lblSpeedConcurrent，然后将其 Text 属性设为：

   varSpeedConcurrent
   

9. 按住 Alt 键并选择 Concurrent 按钮。 系统将创建两个相同的集合，您应该可以注意到，构建时间减少了一半。

   

您可以看到，添加 Concurrent 函数可增强构建集合的性能。 您可以使用此函数同时运行多个流程，请注意，您无法预测 Concurrent 函数中公式开始和结束的顺序， 只要您的结果不依赖于 Concurrent 函数中的其他结果，所有任务都可以同时运行。 此方法可以显著提升您的应用性能。