比较数组与文本框以检查数据库中的重复值

Question

I had no idea of how to call out the method to check if the database has the same Station name if the user was creating it. I managed to store the column of the database to array but I still can't get a way to check. Can anybody help me with it? I kinda stuck now.

This is the code in the button handler that generate the creating of data into database.

 private void btnCreate_Click(object sender, EventArgs e)
    {
        using (testEntities Setupctx = new testEntities())
        {
            station creStation = new station();
            creStation.Station1 = txtStation.Text;
            creStation.Seats = cbSeats.SelectedItem.ToString();
                Setupctx.stations.AddObject(creStation);
                Setupctx.SaveChanges();
                txtStation.Text = "";
                cbSeats.SelectedIndex = -1;
                MessageBox.Show("New Station Has Been Created.");
        }
    }

This is the code that I store the column into the Array.

private string[] StationNameList()
    {
        using (testEntities Setupctx = new testEntities())
        {
            return Setupctx.stations.Select(x => x.Station1).OrderBy(x => x).ToArray();
        }
    }

Can anyone help? Your help will be greatly appreciated.

Answer 1

If you want to check if the station already exist in the data base then in btnCreate_Click before adding the station you may get a list of stations from your method StationNameList and then check if the station name entered in the textbox already exists in the list. You can do

 private void btnCreate_Click(object sender, EventArgs e)
    {
        using (testEntities Setupctx = new testEntities())
        {
         string[] stations = StationNameList();

         if(stations.Contains(txtStation.Text))
              {
              //already exists
              }
         else
              {
              //does not exists
              //your code to insert the new object
              }
        }
   }

Answer 2

Try this

        private void btnCreate_Click(object sender, EventArgs e)
    {
        using (testEntities Setupctx = new testEntities())
        {
            station creStation = new station(){Station1=txtStation.Text,Name=NameTextbox.text,Seats = cbSeats.SelectedItem.ToString()};
            if (!Setupctx.Stations.Any(st => st.Name == creStation.Name))
            {
                Setupctx.stations.AddObject(creStation);
                Setupctx.SaveChanges();
                txtStation.Text = "";
                cbSeats.SelectedIndex = -1;
                MessageBox.Show("New Station Has Been Created.");
            }
        }
    }

I hope this will help , and i expect you has Name property in Station class and is bind to some Textbox in UI.