Question

我正在使用Geared版 LiveCharts 构建WPF数据可视化工具。我有一个名为SectionsCollection的SectionsCollection对象，我需要在数据更改时重新加载。在重新分配到SectionsCollection之前，我运行以下代码段。

        try
        {
            if (SectionsCollection != null && SectionsCollection.Count > 0)
            {
                SectionsCollection.Clear();
            }
        }
        catch(Exception e)
        {
            Status += "Error in clearing SectionsCollection.\n"+e;
        }
        SectionsCollection = new SectionsCollection();

SectionsCollection.Clear();行间歇性地发生以下错误，标签 NullReferenceException发生。

Exception thrown: 'System.NullReferenceException' in LiveCharts.Wpf.dll

Additional information: Object reference not set to an instance of an object.

如果我检查SectionsCollection是否为空并且不为空，为什么会出现此错误？

VisualsCollection和SeriesCollection类型似乎也会出现此错误。

Answer 1

尝试添加标记以防止不需要的多个exec。在你的过程中：

 bool collIsBusy = false;
        try
        {
            if (SectionsCollection != null && SectionsCollection.Count > 0 && !collIsBusy)
            {
                collIsBusy = true; //flag to prevent throttling multiple executions
                SectionsCollection.Clear();
                collIsBusy = false;
            }
        }
        catch (Exception e)
        {
            Status += "Error in clearing SectionsCollection.\n" + e;
        }
        SectionsCollection = new SectionsCollection();

清除WPF LiveCharts中的SectionsCollection

1 个答案: