Select Data from combo box and shows the information to it in List Box c#

Question

I encountered some problem whereby when the user selects the selected name inside the combo box, the data linked with the names selected will show out in the list box. I have problem making into this method. The error falls here.

int selectLocStation = Convert.ToInt32(cbLocStation.SelectedValue);

Error: Unable to cast object of type'<>f_AnonymousType2'2 [System.String.System.Int32]'to type 'System.IConvertible'.

private void cbLocStation_SelectedIndexChanged(object sender, EventArgs e)
    {
        using (satsEntities Setupctx = new satsEntities())
        {
            int selectLocStation = Convert.ToInt32(cbLocStation.SelectedValue);

            var query = (from db in Setupctx.requiredtimings
                         join timing t in Setupctx.timings on db.RequiredTimingID equals t.TimingID
                         where db.RequiredLocationStationID == selectLocStation
                         select new
                         {
                             t.Time2
                         }).ToList();

            List<TimeSpan> lstSelectedTime = new List<TimeSpan>();

            foreach (var a in query)
            {
                lstSelectedTime.Add((TimeSpan)a.Time2);
            }

            lstTime.DataSource = lstSelectedTime;
        }
    }

This is what I do to store data inside the combo box.

using (satsEntities Setupctx = new satsEntities())
        {
            var DeleteRT = (from DelRT in Setupctx.requiredtimings
                            join locationstationname ls in Setupctx.locationstationnames on DelRT.RequiredLocationStationID equals ls.locationstationID
                            select new { ls.locStatname, DelRT.RequiredLocationStationID }).Distinct().ToList();

            cbLocStation.DataSource = DeleteRT.ToList();
            cbLocStation.DisplayMember = "locStatname";
            cbLocStation.ValueMember = "RequiredLocationStationID";

Any help will be greatly appreciated.

Answer 1

  private void Edit_TS_Load(object sender, EventArgs e)
    {
        using (satsEntities Setupctx = new satsEntities())
        {
            var DeleteRT = (from DelRT in Setupctx.requiredtimings
                           join locationstationname ls in Setupctx.locationstationnames on DelRT.RequiredLocationStationID equals ls.locationstationID
                           select new {ls.locStatname, DelRT.RequiredLocationStationID}).Distinct().ToList();

            cbLocStation.DataSource = DeleteRT.ToList();
            cbLocStation.DisplayMember = "locStatname";
            cbLocStation.ValueMember = "RequiredLocationStationID";

        }
    }

Answer is here!

Answer 2

if to string is available I would try this

int selectLocStation = Convert.ToInt32(cbLocStation.SelectedValue.ToString());

or this

int selectLocStation =Int32.Parse(cbLocStation.SelectedValue.ToString());

you can also try this

DataRowView drow = (DataRowView)cbLocStation.SelectedItem;
string str = drow.Row.ItemArray[0].ToString();

check if string has numbers and the convert it to int

you can also add databind

BindingContext oBC = new BindingContext();
    cbLocStation.BindingContext = oBC;
    cbLocStation.DataBindings.Add(new Binding("SelectedValue", DeleteRT, "RequiredLocationStationID", false, DataSourceUpdateMode.OnPropertyChanged));

Answer 3

you are trying to convert the anonymous type from the query into timespan which is not possible since it doesn't implement the IConvertible. you can write a wrapper class and select that class in the query.

var query = (from db in Setupctx.requiredtimings
                         join timing t in Setupctx.timings on db.RequiredTimingID equals t.TimingID
                         where db.RequiredLocationStationID == selectLocStation
                         select new WrapperClass
                         {
                             Time = t.Time2
                         }).ToList();

public class WrapperClass
        {
            public DateTime Time { get; set; }
        }

where time is a DateTime you have defined in the wrapper class