Yоu аre develоping аn аpplicatiоn that allows the user to complete sandwich orders. The user must first select a type and side, then enter the quantity of sandwiches and price per sandwich. Finally, the user must click the calculate button. Given the provided template, write the code to meet these requirements: The user should be able to change the sandwich and amount controls until clicking calculate. When the user clicks Calculate: a. Validate a numeric value that was entered and display any errors using a message box. b. Use selected radio button and combo-box values to concatenate and display a summary. c. Use entered textbox values to calculate and display cost. When the user clicks Clear, clear the textbox, label value and radio-button, combo-box selection. When the user clicks Exit, terminate the application. Directions: Please copy the supplied code below into your answer to this question. Use the spaces to write the missing code and complete the program. namespace MidtermExam{ public partial class frmOrder : Form { // Class-level declarations // Declare decimal constant for Sales Tax Rate of 6% (1 point) // Declare integer variable for Quantity (1 point) // Declare decimal variables for Price, Tax, SubTotal and Cost (1 point) public frmOrder() { InitializeComponent(); } private void btnCalculate_Click(object sender, EventArgs e) { // This procedure calculates the total cost and displays them to the user. // Get the quantity of sandwiches as input from the user. // and Verify that the value is integer and not less than zero. (1 point) if ( ) { // Get the price of each sandwich as input from the user. // and Verify that the value is decimal and not less than zero. (1 point) if ( ) { // Display the Sandwich summary, which is type concatenated with side. (1 point) // Call the Calculate() function and display Cost formated as currency. (1 point) } else { // Display Price error message (1 point) } } else { // Display Quantity error message (1 point) } } private void btnClear_Click(object sender, EventArgs e) { // This procedure resets the controls to default values. (1 point) } private void btnExit_Click(object sender, EventArgs e) { // Close the form. (1 point) } public decimal Calculate() { // This function performs calculations and returns total cost. // Calculate SubTotal = Quantity x Price (1 point) // Calculate Tax = SubTotal x TaxRate (1 point) // Calculate Cost = SubTotal + Tax (1 point) // Return the Cost. (1 point) } }}