在执行另一个按钮之前，如何验证按钮是否被单击

Question

就像标题所说我试图确保在执行第二个按钮之前单击一个按钮。这就是我所拥有的，现在我相信calculateButtonWasClicked = true;超出第二个按钮范围，因此它总是评估为false。有一个更好的方法吗？提前谢谢！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Windows;

namespace priceQuote
{
    public partial class Default : System.Web.UI.Page
    {

        //Declaring Variable
        public bool calculateButtonWasClicked = false;

        protected void Page_Load(object sender, EventArgs e)
        {
            //Disabling the unobtrusive data validation
            UnobtrusiveValidationMode = System.Web.UI.UnobtrusiveValidationMode.None;
    }


        protected void calculateButton_Click(object sender, EventArgs e)
        {
            //Declaring Variables
            decimal salesPrice;
            decimal discountPercent;

            //Attempting to convert user input into decimal data types
            decimal.TryParse(salesPriceBox.Text, out salesPrice);
            decimal.TryParse(discountBox.Text, out discountPercent);

            //Calculating discount amount and assigning the value to a label
            decimal discountAmount = salesPrice * (discountPercent * .01m);
            discountAmountLabel.Text = discountAmount.ToString("c");

            //Calculating total amount and assigning the value to a label
            decimal total = salesPrice - discountAmount;
            totalLabel.Text = total.ToString("c");

            //Changing variable from false to true
            calculateButtonWasClicked = true;
        }

        protected void confirmButton_Click(object sender, EventArgs e)
        {
            if (calculateButtonWasClicked)
            {
                Session["salesPrice"] = salesPriceBox.Text;
                Session["discountAmount"] = discountAmountLabel.Text;
                Session["total"] = totalLabel.Text;

                //Redirecting to new page
                Response.Redirect("~/confirmation.aspx");
            }
            else
            {
                calculateWarningLabel.Text = "Amounts need to be calculated first. Please click calculate button.";
            }
        }

    }
}