Max value of a column using generics

Question

I am working on a project.It's following "Unit of work" pattern.I want to write a Dynamic method where I will pass the table name it will return the max value of primary key column or I will pass the table and column name it will return the max value of that column. It will look something like this--

public int GetMaxPK<T>()
{
    GetMaxId= ??
    return GetMaxId;
}

Is it possible? How can I do this? Or any suggestion?

Answer 1

In my Project,I wrote in mvc controller to get maxId like this--

public class PurchaseOrderController : Controller
{    
   private IPurchaseOrder interfaceRepository;

    public PurchaseOrderController()
    {
        if (interfaceRepository==null)
        {
            this.interfaceRepository= new Repository();
        }
    }
    int maxId=interfaceRepository.GetMaxPK(a=>a.POMSTID);
}

here

a=>a.POMSTID

is the colum selector that you want to query.Suppose you want to select column named "PODETID" then column selector will be like this--

a=>a.PODETID

now in interface --

    public interface IPurchaseOrder:IRepository<PURCHASEORDERMASTER>
    {

    }

Here "PURCHASEORDERMASTER" is my query table or TEntity.

public interface IRepository<TEntity> where TEntity : class
{
    int GetMaxPK(Func<TEntity, decimal> columnSelector);
}

now in the repository(or concrete) class(that inherit the interface) where you call the db you have to write like this--

public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
 {   

    public int GetMaxPK(Func<TEntity, decimal> columnSelector)
    {
        var GetMaxId = db.Set<TEntity>().Max(columnSelector);
        return GetMaxId;
    }
 }

here db is the database context and decimal is the data type of my query column.