DataGridView custom columns C#
Code sample for custom calendar and time column reading data with Entity Framework Core 3x. On a similar topic, for how to use a DataGridViewComboBox with Entity Framework Core see the following Technet article.
SQL-Server database script
The database script found in the Solution items folder must be executed first before running the code.
NuGet packages
Prior to running the project select restore Nuget packages from the root of Solution explorer.