I want to make it so if a person presses enter twice it clears the text box and label box rather than add to the resultvalue

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Ccalculator
{
    public partial class Form1 : Form
    {
        Decimal ResultValue = 0;
        String operatorperformed = "";
        bool IsOperatorPerformed = false;

        public Form1()
        {
            InitializeComponent();
        }

        private void button_Click(object sender, EventArgs e)
        {
            if(textBox1.Text == "0"||IsOperatorPerformed)
            {
                textBox1.Clear();
            }

            Button button = (Button)sender;
            if (textBox1.Text == ".")
            {
                if (!textBox1.Text.Contains("."))
                {
                    textBox1.Text = textBox1.Text + button.Text;
                }
            }else
            textBox1.Text = textBox1.Text + button.Text;
        }

        private void buttonBackSpace_Click(object sender, EventArgs e)
        {
            int i = textBox1.Text.Length;
            textBox1.Text = textBox1.Text.Substring(0, i - 1);
        }

        private void Button_Operator(object sender, EventArgs e)
        {
            Button button = (Button)sender;
            if (ResultValue != 0)
            {
                buttonEqualsTo.PerformClick();
                operatorperformed = button.Text;
                label1.Text = ResultValue + " " +
                    operatorperformed;
                IsOperatorPerformed = true;
            }
            else
            {
                operatorperformed = button.Text;
                ResultValue = Decimal.Parse(textBox1.Text);
                label1.Text = ResultValue + " " + operatorperformed;
                IsOperatorPerformed = true;
            }
        }

        private void buttonEqualsTo_Click(object sender, EventArgs e)
        {
            switch (operatorperformed)
            {
                case "+":
                    textBox1.Text = (ResultValue + Decimal.Parse
                        (textBox1.Text)).ToString();
                    break;
                case "-":
                    textBox1.Text = (ResultValue - Decimal.Parse
                        (textBox1.Text)).ToString();
                    break;
                case "/":
                    textBox1.Text = (ResultValue / Decimal.Parse
                        (textBox1.Text)).ToString();
                    break;
                case "x":
                    textBox1.Text = (ResultValue * Decimal.Parse
                        (textBox1.Text)).ToString();
                    break;
            }
            ResultValue = Decimal.Parse(textBox1.Text);
            label1.Text = "";
        }

        private void buttonC_Click(object sender, EventArgs e)
        {
            textBox1.Clear();
            label1.Text = "";
        }

        private void butCE_Click(object sender, EventArgs e)
        {
            textBox1.Clear();
        }
    }
}