Display all months from (today) and go back 14 months

Question

I have a requirement to return a rolling 14 months to the app. I'm creating an WebAPI

So, I need to go back 14 months from todays date.

I have this so far, but drawing a blank:

[HttpGet("[months]") //allows them to define the months to go back to
public ActionResults ReportingMonths(int months)
{
    var fromDate = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).AddMonths(months);



}

how can I loop through the from date and get all of the months that go back the number of months passed into the call?

Answer 1

do you need the Web API programming pattern too?

[Route("api/[controller]")]  
[ApiController]  
public class ReportsController : ControllerBase  
{  
  
    [HttpGet("{months}")]   
    public ActionResult ReportingMonths(int months = 14)  
    {  
        List<DateTime> dates = new List<DateTime>();  
        DateTime firstOfTheCurrentMonth = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1);  
  
        for (int i = 0; i < months; i++)  
        {  
            dates.Add(firstOfTheCurrentMonth.AddMonths(i * -1));  
        }  
  
        return Ok(dates);  
    }  
}  

If the {months} route parameter is missing then the default is 14; int months = 14.

https://localhost:7208/api/Reports  

If the {months} route parameter exits then the route parameter is used.

https://localhost:7208/api/Reports/2  

It might be a good idea to go through a Web API getting started tutorial and/or read the route reference documentation.

Tutorial: Create a web API with ASP.NET Core
Routing to controller actions in ASP.NET Core

Answer 2

You want a list of dates going back a variable number of months?

static void Main(string[] args)
{
    int months = 14;
    List<DateTime> dates = new List<DateTime>();
    DateTime firstOfTheCurrentMonth = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1);

    for (int i = 0; i < months; i++)
    {
        dates.Add(firstOfTheCurrentMonth.AddMonths(i * -1));
    }

    foreach(DateTime date in dates)
    {
        Console.WriteLine(date.ToShortDateString());
    }

}

Results

6/1/2022
5/1/2022
4/1/2022
3/1/2022
2/1/2022
1/1/2022
12/1/2021
11/1/2021
10/1/2021
9/1/2021
8/1/2021
7/1/2021
6/1/2021
5/1/2021

If you do not want to include this month then...

for (int i = 1; i <= months; i++)