The DialogHost. Show() method affects the rendering speed of the UI when multiple rows are selected in the DataGrid

Bug explanation

After using the DialogHost. Show() method, if multiple rows (over 10000 rows) are selected in the DataGrid, it will seriously affect the rendering speed of the UI. At present, I have found this issue on many computers. If the DataGrid data exceeds tens of thousands of rows, when performing a select all operation, the UI may even lag for more than ten seconds. The same amount of data results in a fast rendering speed before using the DialogHost. Show() method. Visual Studio performance probe analysis was used and it was found that the stuck time was used for GC.

Version

4.9.0

使用 DialogHost.Show() 和包含超过 10,000 行的 WPF DataGrid 重现变慢问题，并比较显示对话框前后全选的行为。使用 Visual Studio 性能分析器确认与 GC 相关的渲染延迟。当大规模选择操作不再产生所报告的数秒 UI 延迟时，即视为完成。