npgsql string to numeric

Question

This is the code:

autoInsert.Parameters.Add(new NpgsqlParameter("price", NpgsqlDbType.Numeric));
autoInsert.Parameters[0].Value = txt_price.Text;
        con.Open();
        autoInsert.ExecuteNonQuery();
        con.Close();

When I execute the query it shows the error: "Input string was not in a correct format." How do I convert that string to Numeric. txt_price is textbox.

Answer 1

In passing Numeric you've assured Npgsql that you were passing a number. Then you passed a string.

If you're already sure, due to other code, that there's a decimal value in txt_price and there couldn't possibly be anything else, then use:

autoInsert.Parameters[0].Value = decimal.Parse(txt_price.Text);

Otherwise, combine it with the code to ensure this, before you do anything else:

decimal price;
if(!decimal.TryParse(txt_price.Text, out price))
{
   //code to display message that txt_price doesn't have a valid value.
   return;
}
using(var con = /*your code that constructs the connection*/)
{
  using(autoInsert = /*your code that returns to command*/)
  {
    autoInsert.Parameters.Add(new NpgsqlParameter("price", NpgsqlDbType.Numeric));
    autoInsert.Parameters[0].Value = price;
    con.Open();
    autoInsert.ExecuteNonQuery();
    con.Close();
  }
}