Visual C++ .NET Examples: Georgetown Cleaning Services

	Visual C++ .NET Examples: Georgetown Cleaning Services

Introduction

Some times if you are asked to create an application for a store that sells a specific number of items based on a fixed list, you may ask for the list of items so you can create its elements in the application. Here is an example:

For such an application, when the list of items changes, you may have to modify the application, recompile, and redistribute (or re-install it). One solution to this problem would consist of providing placeholders for an employee to fill out and process the order with them. Another problem that can be common with this type of application is that, while the form may be crowded with too many objects, most of the time, some items are rarely ordered.

In this exercise, to make this type of application a little more flexible, we will use a few combo boxes that allow the user to simply select the items that are valid for the order.

Practical Learning: Introducing Buttons

Start a new Windows Forms Application named GCS2
Set the form's icon to Drive:\Program Files\Microsoft Visual Studio .NET 2003\Common7\Graphics\icons\Misc\BULLSEYE.ICO
On the main menu, click Project -> Add Resource...
In the Add Resource dialog box, double-click Icon
In the Class View, click IDI_ICON1
In the Properties window, change the filename to Calculate.ico and change the ID to IDI_CALCULATE
Right-click a white area in the drawing section and click New Image Type...
In the New Icon Image Type dialog box, double-click 16x16, 16 Colors
Design it as follows:
Right-click a white area in the drawing section, position the mouse on Current Icon Image Types, and click 32x32, 16 Colors
Right-click a white area in the drawing section and click Delete Image Type
Save the icon
On the main menu, click Project -> Add Resource...
In the Add Resource dialog box, click Icon and click New
In the Class View, click IDI_ICON2
In the Properties window, change the filename to SubTotal.ico and change the ID to IDI_SUBTOTAL
Right-click a white area in the drawing section and click New Image Type...
In the New Icon Image Type dialog box, double-16x16, 16 Colors
Design the icon as follows:
Right-click a white area in the drawing section, position the mouse on Current Icon Image Types, and click 32x32, 16 Colors
Right-click a white area in the drawing section and click Delete Image Type
Save the icon

Return to the form (Form1.h [Design]) and design it as follows:

Control	Name	Text	Additional Properties
GroupBox		Order Identification
Label		Customer Name:
TextBox	txtCustomerName
Label		Date Left:
DateTimePicker	dtpDateLeft		Format: Custom Custom Format: dddd dd MMM yyyy
Label		Time Left:
DateTimePicker	dtpTimeLeft		Format: Time
Label		Date Expected:
DateTimePicker	dtpDateExpected		Format: Custom Custom Format: dddd dd MMM yyyy
Label		Time Expected:
DateTimePicker	dtpTimeExpected		Format: Time
GroupBox		Order Processing
Label		Item Type
Label		Unit Price
Label		Qty
Label		Sub Total
Label		Shirts
TextBox	txtShirtsUnitPrice	0.95	TextAlign: Right
TextBox	txtShirtsQuantity	0	TextAlign: Right
Button	btnCalcShirts		Image: SubTotal.ico
TextBox	txtShirtsSubTotal	0.00	TextAlign: Right
Label		Pants
TextBox	txtPantsUnitPrice	2.75	TextAlign: Right
TextBox	txtPantsQuantity		TextAlign: Right
Button	btnCalcPants		Image: SubTotal.ico
TextBox	txtPantsSubTotal	0.00	TextAlign: Right
ComboBox	cboItem1	None
TextBox	txtItem1UnitPrice	0.00	TextAlign: Right
TextBox	txtItem1Quantity	0	TextAlign: Right
Button	btnCalcItem1		Image: SubTotal.ico
TextBox	txtItem1SubTotal	0.00	TextAlign: Right
ComboBox	cboItem2	None
TextBox	txtItem2UnitPrice	0.00	TextAlign: Right
TextBox	txtItem2Quantity	0	TextAlign: Right
Button	btnCalcItem2		Image: SubTotal.ico
TextBox	txtItem2SubTotal	0.00	TextAlign: Right
ComboBox	cboItem3	None
TextBox	txtItem3UnitPrice	0.00	TextAlign: Right
TextBox	txtItem3Quantity	0	TextAlign: Right
Button	btnCalcItem3		Image: SubTotal.ico
TextBox	txtItem3SubTotal	0.00	TextAlign: Right
ComboBox	cboItem4	None
TextBox	txtItem4UnitPrice	0.00	TextAlign: Right
TextBox	txtItem4Quantity	0	TextAlign: Right
Button	btnCalcItem4		Image: SubTotal.ico
TextBox	txtItem4UnitPrice	0.00	TextAlign: Right
Button	btnCalculate	Calculate
GroupBox		Order Summary
Label		Order Total:
TextBox	txtOrderTotal	0.00	TextAlign: Right
Label		TaxRate
TextBox	txtTaxRate	5.75	TextAlign: Right
Label		%
Label		Tax Amount
TextBox	txtTaxAmount	0.00	TextAlign: Right
Label		Order Price
TextBox	txtOrderPrice	0.00	TextAlign: Right

Click each combo box. Access its Items property and fill it up as follows:
Click OK and save All

Application Implementation

As a dry cleaning applications, there are some behaviors we will apply. About dates, if a customer leaves his or her clothes in the morning before 9AM, we will promise that the clothes can be ready on the same day after 5PM. If a customer leaves the clothes after 9AM, they will be ready only the following day.

To process an order, we provided the clerk with 4 combo boxes to select some of the most regularly ordered cleaning items. The combo boxes also allow the user to type an item that is not in the list. Also, because we can't or we won't predict the prices of these items, we let the user specify their price.

Once an order is ready, we will calculate it using classic operations.

Practical Learning: Implementing the Application

On the form, double-click the Time Left control and implement its ValueChanged event as follows:

System::Void dtpTimeLeft_ValueChanged(System::Object *  sender, System::EventArgs *  e)
{
	 DateTime dateLeft = this->dtpDateLeft->Value;
	 DateTime timeLeft = this->dtpTimeLeft->Value;

	 DateTime time9AM   = DateTime(timeLeft.Year, timeLeft.Month, timeLeft.Day, 9, 0, 0);

	 // If the customer leaves clothes before 9AM...
	 if( timeLeft <= time9AM )
	 {
		 // ... then they should be ready the same day after 5PM
		 this->dtpDateExpected->Value = dateLeft;
		 this->dtpTimeExpected->Value = DateTime(dateLeft.Year, dateLeft.Month, dateLeft.Day, 17, 0, 0);
	 }
	 else
	 {
		 // If the clothese were left after 9AM, they will be availablethe following morning at 8AM
		 this->dtpDateExpected->Value = DateTime(dateLeft.Year, dateLeft.Month, dateLeft.Day + 1); 
		 this->dtpTimeExpected->Value = DateTime(dateLeft.Year, dateLeft.Month, dateLeft.Day + 1, 8, 0, 0);
	 }
}

Return to the form. Double-click the button on the right side of the Shirts text box and implement its Click event as follows:

System::Void btnCalcShirts_Click(System::Object *  sender, System::EventArgs *  e)
{
	 int quantity = 1;
	 double unitPrice, subTotal;

	 // Retrieve the number of this item
	 // Just in case the user types an invalid value, we are using a try...catch
	 try {
		 quantity  = this->txtShirtsQuantity->Text->ToInt16(0);
	 }
	 catch(FormatException *)
	 {
		 MessageBox::Show(S"The value you entered for the number of shirts is not valid"
			              S"\nPlease try again");
	 }

	 // Retrieve the unit price of this item
	 // Just in case the user types an invalid value, we are using a try...catch
	 try {
		 unitPrice = this->txtShirtsUnitPrice->Text->ToDouble(0);
	 }
	 catch(FormatException *)
	 {
		 MessageBox::Show(S"The value you entered for the price of shirts is not valid"
			              S"\nPlease try again");
	 }

	 // Calculate the sub-total for this item
	 subTotal  = quantity * unitPrice;

	 // Display the sub-total in the corresponding text box
	 this->txtShirtsSubTotal->Text = subTotal.ToString(S"F");
}

Return to the form. Double-click the button on the right side of the Pants text bix and implement its Click event as follows:

System::Void btnCalcPants_Click(System::Object *  sender, System::EventArgs *  e)
{
	 int quantity = 1;
	double unitPrice, subTotal;

	try {
		quantity  = this->txtPantsQuantity->Text->ToInt16(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered for the number of pants is not valid"
			             S"\nPlease try again");
	}

	try {
		unitPrice = this->txtPantsUnitPrice->Text->ToDouble(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered for the price of pants is not valid"
			             S"\nPlease try again");
	}

	subTotal  = quantity * unitPrice;

	this->txtPantsSubTotal->Text = subTotal.ToString("F");
}

Return to the form. Double-click the button for the first combo box
Return to the form. Double-click the button for the second combo box
Return to the form. Double-click the button for the third combo box
Return to the form. Double-click the button for the fourth combo box

Implement their Click events as follows:

System::Void btnCalcItem1_Click(System::Object *  sender, System::EventArgs *  e)
{
	int quantity = 1;
	double unitPrice, subTotal;

	try {
		quantity  = this->txtItem1Quantity->Text->ToInt16(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered is not valid"
			             S"\nPlease try again");
	}

	try {
		unitPrice = this->txtItem1UnitPrice->Text->ToDouble(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered for the price is not valid"
			             S"\nPlease try again");
	}

	subTotal  = quantity * unitPrice;

	this->txtItem1SubTotal->Text = subTotal.ToString("F");
}

private: System::Void btnCalcItem2_Click(System::Object *  sender, System::EventArgs *  e)
{
	int quantity = 1;
	double unitPrice, subTotal;

	try {
		quantity  = this->txtItem2Quantity->Text->ToInt16(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered is not valid"
			             S"\nPlease try again");
	}

	try {
		unitPrice = this->txtItem2UnitPrice->Text->ToDouble(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered for the price is not valid"
			             S"\nPlease try again");
	}

	subTotal  = quantity * unitPrice;

	this->txtItem2SubTotal->Text = subTotal.ToString("F");
}

private: System::Void btnCalcItem3_Click(System::Object *  sender, System::EventArgs *  e)
{
	int quantity = 1;
	double unitPrice, subTotal;

	try {
		quantity  = this->txtItem3Quantity->Text->ToInt16(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered is not valid"
			             S"\nPlease try again");
	}

	try {
		unitPrice = this->txtItem3UnitPrice->Text->ToDouble(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered for the price is not valid"
			             S"\nPlease try again");
	}

	subTotal  = quantity * unitPrice;

	this->txtItem3SubTotal->Text = subTotal.ToString("F");
}

private: System::Void btnCalcItem4_Click(System::Object *  sender, System::EventArgs *  e)
{
	int quantity = 1;
	double unitPrice, subTotal;

	try {
		quantity  = this->txtItem4Quantity->Text->ToInt16(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered is not valid"
			             S"\nPlease try again");
	}

	try {
		unitPrice = this->txtItem4UnitPrice->Text->ToDouble(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The value you entered for the price is not valid"
			             S"\nPlease try again");
	}

	subTotal  = quantity * unitPrice;

	this->txtItem4SubTotal->Text = subTotal.ToString("F");
}

Return to the form. Double-click the Calculate button and implement its Click event as follows:

System::Void btnCalculate_Click(System::Object *  sender, System::EventArgs *  e)
{
	double priceShirts, pricePants,
		   priceItem1, priceItem2, priceItem3, priceItem4,
		   totalOrder;
	double taxRate, taxAmount;
	double netPrice;

	// Just in case the user forgot to calculate the sub totals, do it now
	this->btnCalcShirts_Click(sender, e);
	this->btnCalcPants_Click(sender, e);
	this->btnCalcItem1_Click(sender, e);
	this->btnCalcItem2_Click(sender, e);
	this->btnCalcItem3_Click(sender, e);
	this->btnCalcItem4_Click(sender, e);

	// Retrieve the value of the sub-total for each category of items
	priceShirts  = this->txtShirtsSubTotal->Text->ToDouble(0);
	pricePants   = this->txtPantsSubTotal->Text->ToDouble(0);
	priceItem1 = this->txtItem1SubTotal->Text->ToDouble(0);
	priceItem2 = this->txtItem2SubTotal->Text->ToDouble(0);
	priceItem3 = this->txtItem3SubTotal->Text->ToDouble(0);
	priceItem4 = this->txtItem4SubTotal->Text->ToDouble(0);

	// Calculate the total
	totalOrder = priceShirts + pricePants + 
		         priceItem1 + priceItem2 + priceItem3 + priceItem4;

	// Retrieve the value of the tax rate
	try {
		taxRate = this->txtTaxRate->Text->ToDouble(0);
	}
	catch(FormatException *)
	{
		MessageBox::Show(S"The tax rate you entered is invalid"
			             S"\nPlease try again");
	}

	// Calculate the amount owed for the taxes
	taxAmount = totalOrder * taxRate / 100;
	// Add the tax amount to the total order
	netPrice  = totalOrder + taxAmount;
			
	// Display the values of the order summary
	this->txtOrderTotal->Text = totalOrder.ToString("C");
	this->txtTaxAmount->Text  = taxAmount.ToString("C");
	this->txtOrderPrice->Text   = netPrice.ToString("C");
}

Execute the application to test the form
Close the form and return to your programming environment


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