Calling a function with a variable filename in App_Code

Question

User1555333800 posted

Our departments have their own selections of reports.
We need, based on departmentId, to call a list of functions corresponding to their report selections.

Is there a way to call a Function in a file in the App_Code directory when the filename is a variable from a db query?
The function has the same name "ReportData" in all reportfiles

foreach (var filename in listoffilenames_read_from_db_query)
{
var result = filename .ReportData(departmentId);
...
}

Answer 1

User-821857111 posted

You can do this using Reflection. I am assuming that you have a setup along these lines:

App_Code
    Admin.cshtml //reports for Admin
    Sales.cshtml //reports for Sales
    etc

Lets also say you have a function named Test in your reports, and the report takes some parameters:

@functions {
    public static string Test(DateTime startDate, DateTime endDate)
    {
        return "Hello from Admin";
        }
}

You can call this in the following way:

var fileName = "Admin";
var methodName = "Test";
var userParams = new object[] { DateTime.Now.AddDays(-7), DateTime.Now };

var assemblies = AppDomain.CurrentDomain.GetAssemblies().Where(a => a.FullName.StartsWith("App_Code"));
if (assemblies.Any())
{
    var assembly = assemblies.FirstOrDefault(a => a.DefinedTypes.Any(d => d.Name == fileName));
    var method = assembly.DefinedTypes.First(d => d.Name == fileName).DeclaredMethods.FirstOrDefault(m => m.Name == methodName);
    var message = method.Invoke(null, userParams);
}

Answer 2

User1555333800 posted

Thank You, Mike. 
This was new to me!

Learning something new every day!