使用listview从数据库的表中删除行

Question

I want to know how to delete a row from a table in the database using listview and button.

My code

private void deleteitems()
{
    //DELETE FROM Tbl_Cashier WHERE RecpieId = @RecpieId AND IngredientId = @IngredientId
    string query = "delete from Tbl_Cashier where Cashier_ID = '" + listView1.SelectedIndices+"' ";

    using (SqlConnection connection = new SqlConnection(connectionString1))
    using (SqlCommand command = new SqlCommand(query, connection))
    {
        connection.Open();
        command.Parameters.Remove(listView1.SelectedIndices);

        command.ExecuteNonQuery();
        connection.Close();
    }

    MessageBox.Show("You will see the new data with your next restart of the application", "INFO", MessageBoxButtons.OK, MessageBoxIcon.Information);
}

I am getting this error:

An unhandled exception of type 'System.InvalidCastException' occurred in System.Data.dll

Additional information: The SqlParameterCollection only accepts non-null SqlParameter type objects, not SelectedIndexCollection objects.

Answer 1

You should remove this line:
command.Parameters.Remove(listView1.SelectedIndicies)

And then you should loop over the selection-indicies and fire a query for each selected item, like this:

private void deleteitems()
{    
    using (SqlConnection connection = new SqlConnection(connectionString1))
    {
        connection.Open();
        foreach(var index in listView1.SelectedIndicies)
        {
            // Modify this to get the 'cashier_id' from you listView at the specified row index...
            // You should also consider using a prepared query...
            string query = "delete from Tbl_Cashier where Cashier_ID = '" + index +"' ";
            using (SqlCommand command = new SqlCommand(query, connection))
            {
                // consider checking the return value here if the delete command was successful
                command.ExecuteNonQuery();
            }
        }
    }
    MessageBox.Show("You will see the new data with your next restart of the application", "INFO", MessageBoxButtons.OK, MessageBoxIcon.Information);
}

** not tested **

Answer 2

When you mentioned "a Row", we can assume that you only wish to delete one row from your database table.

Another important assumption is that the first column of your listview contains the Cashier_ID of your database table.

Thus, here's what you need to do:

private void DeleteSelectedItemFromListView() {

        var cashierId = listView1.FocusedItem.Text;

        string query = "delete from Tbl_Cashier where Cashier_ID=@id;";

        using (SqlConnection con = new SqlConnection(connectionString1)) {

            try {

                con.Open();

                using (SqlTransaction trans = con.BeginTransaction()) {

                    using (SqlCommand com = new SqlCommand(query, con, trans)) {

                        com.Parameters.AddWithValue("id", cashierId);

                        var should_be_one = com.ExecuteNonQuery();

                        if (should_be_one == 1) {

                            trans.Commit();

                        } else {

                            trans.Rollback();

                            throw new Exception("An attempt to delete multiple rows was detected");
                        }

                    }

                }


            } catch (Exception ex) {
                MessageBox.Show(ex.Message);
            } finally {
                con.Close();
            }

        }

    }

However, if you wish to delete several items from your listview (multiple selected items), that's a different story.