EF Core string to datetime/datetimeoffset value converter example with CAST SQL generation

program.cs

using Microsoft.EntityFrameworkCore;

Console.WriteLine("Hello, World!");
using var x = new MyDbContext();
x.Database.EnsureCreated();

var paramValueDateTimeOffset = DateTimeOffset.Now.AddDays(-1);
var paramValueDateTime = DateTime.Now.AddDays(-1);

var query = x.CustomerLeases.Where(c => c.TextDateTime >= DateTimeOffset.Now
                                        && c.TextDateTime >= DateTime.Now
                                        && c.TextDateTime >= paramValueDateTimeOffset
                                        && c.TextDateTime >= paramValueDateTime
                                        );

// If you use date param inside the query it will not generate a SQL statement with CAST for the column
// But if you use the datetimeoffset parameter type it will generate the CAST statement for the column

/*
DECLARE @__paramValueDateTimeOffset_0 datetimeoffset = '2022-01-22T23:16:28.2471153+11:00';
DECLARE @__paramValueDateTime_1 nvarchar(48) = N'2022-01-22 23:16:28.2494416';

SELECT [c].[Id], [c].[TextDateTime]
FROM [CustomerLeases] AS [c]
WHERE (((CAST([c].[TextDateTime] AS datetimeoffset) >= SYSDATETIMEOFFSET()) AND 
([c].[TextDateTime] >= GETDATE())) AND (CAST([c].[TextDateTime] AS datetimeoffset) >= @__paramValueDateTimeOffset_0)) AND 
([c].[TextDateTime] >= @__paramValueDateTime_1)

*/

Console.WriteLine(query.ToQueryString());
var result = query.ToList();
Console.ReadLine();

public class MyDbContext : DbContext
{
    public DbSet<CustomerLease> CustomerLeases { get; set; }

    public MyDbContext()
    {
    }

    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlServer("data source=.;Initial Catalog = TestDb; Integrated Security = True;");

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder
            .Entity<CustomerLease>()
            .Property(c => c.TextDateTime)
            .HasConversion<string>();

        base.OnModelCreating(modelBuilder);
    }
}
public class CustomerLease
{
    public int Id { get; set; }
    public DateTime TextDateTime { get; set; }
}