Checkbox in DataGridView doesnt Check

Question

I create a DataGridView as follows

 private void IniciarGV()
    {
        using (var db = new Entities())
        {

            var ListaPantallas = (from a in db.PANTALLAS
                                  select a).ToList();


            if (ListaPantallas != null)
            {

                gvPermisos.DataSource = ListaPantallas;
                gvPermisos.Columns["idPantalla"].Visible = false;
                gvPermisos.Columns["nombrepantalla"].HeaderText = "Nombre";
                //gvPermisos.Columns.Add(new DataGridViewCheckBoxColumn());
                DataGridViewCheckBoxColumn checkBoxColumn = new DataGridViewCheckBoxColumn();
                checkBoxColumn.HeaderText = "Seleccione";
                checkBoxColumn.Width = 50;
                checkBoxColumn.Name = "checkBoxColumn";
                gvPermisos.Columns.Insert(0, checkBoxColumn);
                //gvPermisos.EndEdit();

            }

            db.Dispose();
        }
    }

After that a i retrieve the privileges with the same method linq

var TraerPermisos = (from a in db.PERMISOS
                                 where a.IDUSUARIO == UsuarioEditar.idUsuario
                                 select a).ToList();

After i go through the gridview to match the privileges with the ids that i wanted to check so the user can edit them, but for some reason they always appear unmarked

so far this is what i encounter in every forum or google, but it doesnt seem to work

 foreach (PERMISOS item in TraerPermisos)
            {
                foreach (DataGridViewRow row in gvPermisos.Rows)
                {
                    var ValorPermisoEnGV = Convert.ToBoolean(row.Cells["checkBoxColumn"].Value);
                    var ValorPantalla = decimal.Parse(row.Cells["idPantalla"].Value.ToString());
                    if (ValorPantalla == item.IDPANTALLA)
                    {
                        row.Cells["checkBoxColumn"].Value = true;
                    }
                }
            }

this what my form looks like

I load the privileges on start

 public ManejarUsuario()
    {
        InitializeComponent();
        IniciarComboBox();
        IniciarGV();
        if (UsuarioEditar.idUsuario != 0)
        {
            CargarDatos();
            btnCrearUsuario.Text = "Editar";
            CargarPrivilegios();
        }
    }

Sorry about the long post, i've tried so many options but none seems to work

Answer 1

Life would be a lot easier if you just put a Boolean in the data driving the grid. First, let's make a holder class for your info

class Perms{
  public int IdPantalla { get; set; }
  public string NombrePantalla { get; set; }
  public bool HasPermission { get; set; }
}

Then let's have the query produce a list of these instead:

//get all the IDPANTALLA this user has and put in a hash set
var TraerPermisos = (from a in db.PERMISOS
    where a.IDUSUARIO == UsuarioEditar.idUsuario
    select a.IDPANTALLA).ToHashSet();

//make a list of objects that includes a bool of whether the user has that permission 
//note you should have this be a class level variable for ease of use later/elsewhere 
ListaPantallas = (from a in db.PANTALLAS
    select new Perms { 
      IdPantalla a.IdPantalla, 
      HasPermission = TraerPermisos.Contains(a.idPantalla) , 
      NombrePantalla = a.nombrepantalla 
    }).ToList();

Then set up the grid:

gvPermisos.DataSource = ListaPantallas;
gvPermisos.Columns["IdPantalla"].Visible = false;
gvPermisos.Columns[ "NombrePantalla"].HeaderText = "Nombre";
gvPermisos.Columns[ "HadPermission"].HeaderText = "Seleccione";

The grid will find the bool property in the list and wire it up for you as a check column. It doesn't need you to make a column for it. Anything you tick is then stored in the underlying list as a true/false and you can eg foreach(var x in ListaPantallas) if(x.HasPermission...

When manipulating data in a DGV that is bound to a data source, manipulate the source. Also consider to make Perms implements INotifyPropertyChanged (and consider switching to using a binding list)