The input string was not in correct format

Question

I'm new into c# programming and I can't get this code. The error I get is

input string was not in correct format.

I know it's a duplicate question, but what I have found so far, didnt' helped me much. I'm using the code below in order to insert some data into a mssql database.

public void btnAdauga_Click(object sender, EventArgs e)
{
    try
    {
        using (SqlConnection con = new SqlConnection(cs))
        {
            con.Open();
            SqlCommand cmd = new SqlCommand(insert, con);
            cmd.Parameters.AddWithValue("@IDAutocar", txtID.Text);
            cmd.Parameters.AddWithValue("@IDTipAutocar", txtIDTip.Text);
            cmd.Parameters.AddWithValue("@TipAutocar", int.Parse(cmbTip.SelectedValue.ToString()));
            int val = cmd.ExecuteNonQuery();
            MessageBox.Show(val + "Autocarul a fost adaugat cu succes!");
            con.Close();
            this.Dispose();
        }
    }

    catch (Exception er){MessageBox.Show(er.Message);}
}

The insert statement: string insert = "INSERT INTO Autocare (IDAutocar, IDTipAutocar, TipAutocar) VALUES (@IDAutocar, @IDTipAutocar, @TipAutocar)";

The error is at this line of code: cmd.Parameters.AddWithValue("@TipAutocar", int.Parse(cmbTip.SelectedValue.ToString())); Could anyone enlighten me what I am missing? Thanks

Answer 1

Try using Int.TryParse function instead of Int.Parse and handle parsing exceptions before that line. Like this:

        using (SqlConnection con = new SqlConnection(cs))
        {
            con.Open();
            SqlCommand cmd = new SqlCommand(insert, con);
            cmd.Parameters.AddWithValue("@IDAutocar", txtID.Text);
            cmd.Parameters.AddWithValue("@IDTipAutocar", txtIDTip.Text);

            int tipAutocar = 0;
            if (int.TryParse(cmbTip.SelectedValue.ToString(), out tipAutocar))
            {
                //if successful
                cmd.Parameters.AddWithValue("@TipAutocar", tipAutocar));
            }
            else
            {
                //if not successful, do sth else
            }

            int val = cmd.ExecuteNonQuery();
            MessageBox.Show(val + "Autocarul a fost adaugat cu succes!");
            con.Close();
            this.Dispose();
        }

Answer 2

If your combobox contains int values as strings, then use

int.Parse(cmbTip.Text);

If you want the index of the selected text, then use

int.Parse(cmbTip.SelectedIndex);

Answer 3

According to Yeldar suggestion, I have removed int.Parse and use only combo.SelectedValue and it worked!

Answer 4

1. Debug properly with breakpoints and step into the code, and in debug menu add the variables of interest in the "Watch" window or look for them in the "Locals" window while debugging. [for eg cmbTip.SelectedValue.ToString() ]
2. As pointed by others cmbTip.SelectedValue.ToString() could be the reason for the exception.
3. for cmbTip even after selecting the value the error persists, or the selectedValue comes as NULL, try to using SelectedText