How to connect MySQL database? this code base,there were no erors. But can not insert data

using MySql.Data.MySqlClient;
using System.Data;

public String connectionString = @"server=localhost;port=3306;user id=root;database=Product;persistsecurityinfo=True;password=xxxxxx@;";


protected void btnInsert_Click(object sender, EventArgs e)
{
    MySqlConnection mySqlCon = new MySqlConnection(connectionString);

    try
    {
        using (mySqlCon)
        {
            mySqlCon.Open();

            MySqlCommand mySqlCmd = new MySqlCommand("Proc_Store_Products", mySqlCon);
            mySqlCmd.CommandType = CommandType.StoredProcedure;
            mySqlCmd.Parameters.AddWithValue("_productId", Convert.ToInt32(hfProductID.Value == "" ? "0" : hfProductID.Value));
            mySqlCmd.Parameters.AddWithValue("_productCode", txtproductCode.Text.Trim());
            mySqlCmd.Parameters.AddWithValue("_productName", txtproductName.Text.Trim());
            mySqlCmd.Parameters.AddWithValue("_price", Convert.ToDecimal(txtprice.Text.Trim()));
            mySqlCmd.Parameters.AddWithValue("_description", txtdescription.Text.Trim());

            mySqlCmd.ExecuteNonQuery();

            clear();
            lblSuccessMsg.Text = "Submitted Successfully";
        }


    }
    catch (Exception ex)
    {
        lblErrorMsg.Text = ex.Message;
    }

This is the SP code

DELIMITER $$ 
CREATE DEFINER=root@localhost PROCEDURE Proc_Store_Products(
    _productId int, 
    _productCode varchar(20), 
    _productName varchar(40), 
    _price decimal(18,2), 
    _stock int, 
    _description varchar(200)
) BEGIN
IF _productId = 0 then
    INSERT INTO productInfo(productCode,productName,price,stock,description) 
    VALUES(_productCode,_productName,_price,_stock,_description);

else
    UPDATE productInfo
    SET
    productCode = _productCode,
    productName = _productName,
    price = _price,
    stock = _stock,
    description = _description
    WHERE
    productId = _productId;

END IF;
END$$ DELIMITER ;

Copyright Notice：Content Author:「Dinuwan Kalubowila」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/56697936/how-to-connect-mysql-database-this-code-base-there-were-no-erors-but-can-not-i