Find specific character in string property from list of objects

Question

I need to filter a list of objects according to whether a specific property (String type) contains the character 'S' (or 'N') in position 19.

I have this in C#:

IQueryable<Tabla5> lstTipoGasto = objServiceClient.ListaTabla5(int.Parse(number)).AsQueryable();
Tabla5 objTipoGasto = new Tabla5();
objTipoGasto.NombreNom5 = "Seleccione..";
objTipoGasto.CodigoNom5 = -1;
objTipoGasto.TextNom5 = "...";
List<Tabla5> lst = lstTipoGasto.ToList();
lst.Add(objTipoGasto);
lstTipoGasto = lst.AsQueryable();

var lista = lstTipoGasto.AsEnumerable().ToList().Where(x => x.AgregaTabl.Contains("S"))
    .Select(x => new 
    { 
        x.CodigoNom5, 
        x.NombreNom5, 
        x.TextNom5, 
        x.AgregaTabl 
    }).OrderBy(x => x.CodigoNom5).ToList();

uddlTipoGasto.DataSource = lista;            
uddlTipoGasto.DisplayMember = "NombreNom5";
uddlTipoGasto.ValueMember = "CodigoNom5";
uddlTipoGasto.ValueMember = "TextNom5";

I get an exception. Any ideas why?

What is the exception message? Also your code doesn't check the character at position 19 right now. — Rahul Singh, Aug 03 '15 at 14:34
It doesn't seem like you're checking position 19, you're just using `Contains()`.. — haim770, Aug 03 '15 at 14:36
The exception is (in spanish): Referencia a objeto no establecida como instancia de un objeto. — Rafael Giraldo, Aug 03 '15 at 14:39
The original query: `var lista = lstTipoGasto.AsEnumerable().ToList().Where(x => x.AgregaTabl.Substring(18, 1).Equals("S")).Select(x => new { x.CodigoNom5, x.NombreNom5, x.TextNom5, x.AgregaTabl }).OrderBy(x => x.CodigoNom5).ToList();` — Rafael Giraldo, Aug 03 '15 at 14:42

Shar1er80 · Accepted Answer · 2015-08-03T15:37:44.203

Try...

var lista = lstTipoGasto.AsEnumerable()
    .ToList()
    .Where(x => x.AgregaTabl.Length > 18 && 
           (x.AgregaTabl[18] == 'S' || x.AgregaTabl[18] == 'N'))
    .Select(x => new 
    { 
        x.CodigoNom5, 
        x.NombreNom5, 
        x.TextNom5, 
        x.AgregaTabl 
    }).OrderBy(x => x.CodigoNom5).ToList();

Instead of checking if x.AgregaTabl.Contains("S"), you check that x.AgregaTabl.Length > 18 so we know that it has at least 19 characters, then we check (x.AgregaTabl[18] == 'S' || x.AgregaTabl[18] == 'N') to see if the 19th character is 'S' or 'N' (Note: x.AgregaTabl[18] accesses the 19th character due to 0-based indices).

Find specific character in string property from list of objects

1 Answers1