How to access at run-time the value of an IEnumerable<T>

Jose Daniel Navarro Brito 61

Good day all:

I'm developing a WEB API that returns a paged response to a jQuerydatatable end point. Because the code repeats itself, I encapsulated all the logic in the generic procedure below. The code works perfectly when I pass the class (entity) I want the SQL stored procedure to page. The issue is that I want to access the value of two of the properties return by the IEnumerable <T> namely TotalCount and FilteredCount which are always returned by the stored procedure

public async Task<OutgoingResponseToEndPointDatatable<T>> SendingDataBackToEndPointJqueryDatatable(OncomingEndPointDatatableRequest request, string NameOfStoredProcedure)

{

 var parameters = new StoredProcedureParameters()

 {

     PageNo = Convert.ToInt32(request.start / request.length),

     PageSize = request.length,

     SortColumn = request.Order[0].Column,

     SortDirection = request.Order[0].Dir,

     SearchValue = request.Search != null ? request.Search.Value.Trim() : ""

 };

 IEnumerable<T> outcome= await  _db.LoadPaginationSearchAndSortingStoredProcedure<T, dynamic>(storedProcedure: NameOfStoredProcedure, parameters: parameters);

How I can refer to the int values of the TotalCount and FitredCount properties return by the procedure above? I tried using var properies=trypeof(T). GetProperties but an object is return and I want to access to the int values not the object.

1 answer

Bruce (SqlWork.com) 68,486

implement an interface (or base class) implemented by the sp return classes

	public interface IQueryResult
	{
		int TotalCount {get; set;}
		int FilteredCount {get; set;}
	}

then require the interface in the method definition

public T Test<T>(T p) where T: IQueryResult
{
}

Jose Daniel Navarro Brito 61

Hi Bruce:

Thanks for your response, I found your idea but I thinks that you need a bit more information so you can guide me more properly.

I have already an Interface

interface  IJQueryDatatableInterface<T>
{ 
    Task<OutgoingResponseToEndPointDatatable<T>> SendingDataBackToEndPointJqueryDatatable(OncomingEndPointDatatableRequest request, string NameOfStoredProcedure);
    Task <IEnumerable<T>> LoadPaginationSearchAndSortingStoredProcedure(string NameOfStoredProcedure, StoredProcedureParameters sp_parameters);
}

This class below implements the above interface as follows:

public class QueryDatatable<T>: IJQueryDatatableInterface<T> where T : class
  {
      private readonly ISqlDatabaseAccess _db;
      public QueryDatatable(ISqlDatabaseAccess db)
      {           
          _db = db;
      }
  
      public async Task<OutgoingResponseToEndPointDatatable<T>> SendingDataBackToEndPointJqueryDatatable(OncomingEndPointDatatableRequest request, string NameOfStoredProcedure)
      {
          var parameters = new StoredProcedureParameters()
          {
              PageNo = Convert.ToInt32(request.start / request.length),
              PageSize = request.length,
              SortColumn = request.Order[0].Column,
              SortDirection = request.Order[0].Dir,
              SearchValue = request.Search != null ? request.Search.Value.Trim() : ""
          };
          IEnumerable<T> outcome= await  _db.LoadPaginationSearchAndSortingStoredProcedure<T, dynamic>(storedProcedure: NameOfStoredProcedure, parameters: parameters);                       
          List<T> listado = outcome.ToList();

Why like this ? ..I intend to pass a class or entity as a parameter to the SQL Stored procedure pagination, search and sort method ....in other words, I pass the entity and select the stored procedure that page, filter and sort that particular entity reason why I implement:

public class QueryDatatable<T>: IJQueryDatatableInterface<T> where T : class

public class QueryDatatable<T>: IJQueryDatatableInterface<T> where T : class

Finally the minimun API call the above method as follows

app.MapPost("/ProjectReportView3", async (IJQueryDatatableInterface<ProgressreportView> data, OncomingEndPointDatatableRequest request) =>
{
    var contractors = await data.SendingDataBackToEndPointJqueryDatatable(request,NameOfStoredProcedure: "dbo.sp_ProgressreportView");
    if (contractors == null)
        return Results.NotFound("Sorry, there are not records");
    return Results.Ok(contractors);
}).WithName("PagedReportView3");

As you can see the <T> class or entity is pass to the method and the stored procedure do the paging, search of the entity, This is the class

public class ProgressreportView
{
    public decimal? Plot { get; set; }
    public string? Status { get; set; }
    public DateOnly ReportDate { get; set; }
    public string? Contractor { get; set; }
    public string? Projectname { get; set; }
    public string? Tipologyname { get; set; }
    public string? Inspector { get; set; }
    public int? FilteredCount { get; set; }
    public int? TotalCount { get; set; } 
}

The stored procedure method return all these fields, the issue is that they are returned as together as an array . As per the code snippet below, I have to "separate"the RecordsTotal and RecordsFiltered from the array to in order to return the correct reponse to the end point Jquery datatable.

return new OutgoingResponseToEndPointDatatable<T> ()
 {
     Draw = request.draw,
     RecordsTotal = dataArray[0].TotalCount,
     RecordsFiltered = dataArray[0].FilteredCount,
     Data = dataArray.ToList(),
    
 };

I failed to comprehend how the IQueryresult interface can be implemented?. Can you guide me after this explanation please?

Bruce (SqlWork.com) 68,486

just require and implement:

interface  IJQueryDatatableInterface<T> where T: IQueryResult
{ 
    Task<OutgoingResponseToEndPointDatatable<T>> SendingDataBackToEndPointJqueryDatatable(OncomingEndPointDatatableRequest request, string NameOfStoredProcedure);
    Task <IEnumerable<T>> LoadPaginationSearchAndSortingStoredProcedure(string NameOfStoredProcedure, StoredProcedureParameters sp_parameters);
}

implement in response class:

public class ProgressreportView : IQueryResult
{
    public decimal? Plot { get; set; }
    public string? Status { get; set; }
    public DateOnly ReportDate { get; set; }
    public string? Contractor { get; set; }
    public string? Projectname { get; set; }
    public string? Tipologyname { get; set; }
    public string? Inspector { get; set; }
    public int FilteredCount { get; set; } = 0;
    public int TotalCount { get; set; } = 0;
}

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How to access at run-time the value of an IEnumerable<T>

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