How can I make a MVC lambda filter

Question

I’m making a simple filter, and show the data on the page.

The code I’m using is this:

mt.ModelItens = db.Forecast
                  .Where(f => (f.CanalForecast.area == idArea && f.CanalForecast.despesa == idDespesa))
                  .ToPagedList(mt.ModelPaging.page, mt.ModelPaging.pageSizeSelected);

This code works very well if the two fields are selected, because if only one is selected it shows nothing.

Referent here:

.Where(f => (f.CanalForecast.area == idArea && f.CanalForecast.despesa == idDespesa))

My problem is that I want it to work by selecting an ex. field (Area) and also by selecting the two fields (Area and Expense).

I don’t know if I got past the real problem now.

Answer 1

Better you target this search by testing what is filled:

var query = db.Forecast;
if (idArea != null) {
    query = query.Where(f => f.CanalForecast.area == idArea);
}

if (idDespesa != null) {
    query = query.Where(f => f.CanalForecast.despesa == idDespesa);
}

mt.ModelItens = query
                .OrderByDescending(entity => entity.idForecast)
                .ToPagedList(mt.ModelPaging.page, mt.ModelPaging.pageSizeSelected);