Lists-Based Applications: The Music Store

The DataSet of the .NET Framework is a very impressive class. It allows you to create and manage any type of list, making it a central point for a list-based application, although it is highly used in formal database applications such as those intended for Microsoft SQL Server or Microsoft Access.

To support the creation and management of any type of list, the DataSet class has complete built-in mechanisms for creating tables, their associated columns, and to perform data entry. To demonstrate these functionalities of the DataSet, we are going to create a list-based application that can serve as another introduction to databases. The application simulates a music instrument store that processes orders for customers.

When a customer places an order in the store to purchase a product, the employee can select items by categories, specify the quantity, calculate the total order, and save it.

1. Start Microsoft Visual Studio .NET and create a new Windows Application named MusicStore2
2. To add a new form, on the main menu, click Project -> Windows Form...
3. Set the Name to DataCenter and press Enter
4. To add a new form, on the main menu, click Project -> Windows Form...
5. Set the Name to Categories and press Enter
6. Design the form as follows:
    

   Control Name Text Other Properties DataGrid     Auto Format: Professional 3 Label   New Category:   TextBox txtNewCategory     Button btnAdd Add   Button btnClose Close   Form     AcceptButton: btnAdd CancelButton: btnClose FormBorderStyle: FixedDialog MaximizeBox: False ShowInTaskbar: False StartPosition: CenterScreen

7. To add a new form, on the main menu, click Project -> Windows Form...
8. Set the Name to ItemTypes and press Enter
9. Design the form as follows:
    

   Control Name Text Other Properties DataGrid     Auto Format: Professional 3 Label   New Item Type:   TextBox txtNewItemType     Button btnAdd Add   Button btnClose Close   Form     AcceptButton: btnAdd CancelButton: btnClose FormBorderStyle: FixedDialog MaximizeBox: False ShowInTaskbar: False StartPosition: CenterScreen

10. To add a new form, on the main menu, click Project -> Windows Form...
11. Set the Name to NewStoreItem and press Enter
12. Design the form as follows:
     

    Control Name Text Other Properties Label   Category:   ComboBox cboCategories   DropDownStyle: DropDownList Sorted: True Button btnNewCategory New   Label   Item Type:   ComboBox cboItemTypes   DropDownStyle: DropDownList Sorted: True Button btnNewType New   Label   Item Name:   TextBox txtItemName     Label   Unit Price:   TextBox txtUnitPrice 0.00 AlignText: Right Label   Item #:   TextBox txtItemNumber     Button btnCreate Create   Button btnClose Close   Form     AcceptButton: btnCreate CancelButton: btnClose MaximizeBox: False StartPosition: CenterScreen

13. Double-click an unoccupied area of the form to access its Load event and implement its as follows:
     

    private void NewStoreItem_Load(object sender, System.EventArgs e) { // We will generate a random number for the store item DateTime tmeNow = DateTime.Now; Random rndNumber = new Random(tmeNow.Millisecond); string strNumber = rndNumber.Next(100000, 999999).ToString(); // Display the new number in the Part # text box this.txtItemNumber.Text = strNumber; // Disable the OK button to indicate that the item is not ready this.btnCreate.Enabled = false; }

14. Return to the NewStoreItem form
15. Double-click the top New button on the right side of the Category combo box and implement its event as follows:
     

    private void btnNewCategory_Click(object sender, System.EventArgs e) { Categories frmCat = new Categories(); frmCat.ShowDialog(); }

16. Return to the NewStoreItem form and double-click the lower New button
17. Implement the Click event as follows:
     

    private void btnNewType_Click(object sender, System.EventArgs e) { ItemTypes frmTypes = new ItemTypes(); frmTypes.ShowDialog(); }

18. To add a new form, on the main menu, click Project -> Add Windows Form...
19. Set the Name to PurchaseOrder and press Enter
20. Design the form as follows:
     

    Control Name Text Other Properties GroupBox   Selection of Sale Item   Label   Category   Label   Types   Label   Available Items   Button btnNewItem New Item   ListBox lbxCategories     ListBox lbxItemTypes     ListBox lbxAvailableItems     GroupBox   Items Sold   Label   Item #   Label   Item Name   Label   Unit Price   Label   Qty   Label   Sub Total   TextBox txtItemNumber1     TextBox txtItemName1     TextBox txtUnitPrice1 0.00 AlignText: Right TextBox txtQuantity1 0 AlignText: Right TextBox txtSubTotal1 0.00 AlignText: Right TextBox txtItemNumber2     TextBox txtItemName2     TextBox txtUnitPrice2 0.00 AlignText: Right TextBox txtQuantity2 0 AlignText: Right TextBox txtSubTotal2 0.00 AlignText: Right TextBox txtItemNumber3     TextBox txtItemName3     TextBox txtUnitPrice3 0.00 AlignText: Right TextBox txtQuantity3 0 AlignText: Right TextBox txtSubTotal3 0.00 AlignText: Right TextBox txtItemNumber4     TextBox txtItemName4     TextBox txtUnitPrice4 0.00 AlignText: Right TextBox txtQuantity4 0 AlignText: Right TextBox txtSubTotal4 0.00 AlignText: Right TextBox txtItemNumber5     TextBox txtItemName5     TextBox txtUnitPrice5 0.00 AlignText: Right TextBox txtQuantity5 0 AlignText: Right TextBox txtSubTotal5 0.00 AlignText: Right TextBox txtItemNumber6     TextBox txtItemName6     TextBox txtUnitPrice6 0.00 AlignText: Right TextBox txtQuantity6 0 AlignText: Right TextBox txtSubTotal6 0.00 AlignText: Right GroupBox   Order Processing   Button btnCalculate Calculate Order   Button btnSave Add to Today's Orders   Button btnClose Close   Label   Total Order:   TextBox txtTotalOrder 0.00 AlignText: Right Form     CancelButton: btnClose MaximizeBox: False StartPosition: CenterScreen

21. Double-click the NewItem button
22. Implement its Click event as follows:
     

    private void btnNewItem_Click(object sender, System.EventArgs e) { NewStoreItem frm = new NewStoreItem(); frm.ShowDialog(); }

23. Double-click the Calculate Order button and implement its Click event as follows:
     

    private void btnCalculate_Click(object sender, System.EventArgs e) { decimal item1UnitPrice= 0.00M, item2UnitPrice= 0.00M, item3UnitPrice= 0.00M, item4UnitPrice= 0.00M, item5UnitPrice= 0.00M, item6UnitPrice= 0.00M; int quantity1 = 0, quantity2 = 0, quantity3 = 0, quantity4 = 0, quantity5 = 0, quantity6 = 0; decimal item1SubTotal= 0.00M, item2SubTotal= 0.00M, item3SubTotal= 0.00M, item4SubTotal= 0.00M, item5SubTotal= 0.00M, item6SubTotal= 0.00M; decimal totalOrder; try { item1UnitPrice = decimal.Parse(this.txtUnitPrice1.Text); } catch(FormatException ) { MessageBox.Show("Invalid Unit Price"); this.txtUnitPrice1.Text = "0.00"; this.txtUnitPrice1.Focus(); } try { quantity1 = int.Parse(this.txtQuantity1.Text); } catch(FormatException ) { MessageBox.Show("Invalid Quantity"); this.txtQuantity1.Text = "0"; this.txtQuantity1.Focus(); } try { item2UnitPrice = decimal.Parse(this.txtUnitPrice2.Text); } catch(FormatException ) { MessageBox.Show("Invalid Unit Price"); this.txtUnitPrice2.Text = "0.00"; this.txtUnitPrice2.Focus(); } try { quantity2 = int.Parse(this.txtQuantity2.Text); } catch(FormatException ) { MessageBox.Show("Invalid Quantity"); this.txtQuantity2.Text = "0"; this.txtQuantity2.Focus(); } try { item3UnitPrice = decimal.Parse(this.txtUnitPrice3.Text); } catch(FormatException ) { MessageBox.Show("Invalid Unit Price"); this.txtUnitPrice3.Text = "0.00"; this.txtUnitPrice3.Focus(); } try { quantity3 = int.Parse(this.txtQuantity3.Text); } catch(FormatException ) { MessageBox.Show("Invalid Quantity"); this.txtQuantity3.Text = "0"; this.txtQuantity3.Focus(); } try { item4UnitPrice = decimal.Parse(this.txtUnitPrice4.Text); } catch(FormatException ) { MessageBox.Show("Invalid Unit Price"); this.txtUnitPrice4.Text = "0.00"; this.txtUnitPrice4.Focus(); } try { quantity4 = int.Parse(this.txtQuantity4.Text); } catch(FormatException ) { MessageBox.Show("Invalid Quantity"); this.txtQuantity4.Text = "0"; this.txtQuantity4.Focus(); } try { item5UnitPrice = decimal.Parse(this.txtUnitPrice5.Text); } catch(FormatException ) { MessageBox.Show("Invalid Unit Price"); this.txtUnitPrice5.Text = "0.00"; this.txtUnitPrice5.Focus(); } try { quantity5 = int.Parse(this.txtQuantity5.Text); } catch(FormatException ) { MessageBox.Show("Invalid Quantity"); this.txtQuantity5.Text = "0"; this.txtQuantity5.Focus(); } try { item6UnitPrice = decimal.Parse(this.txtUnitPrice6.Text); } catch(FormatException ) { MessageBox.Show("Invalid Unit Price"); this.txtUnitPrice6.Text = "0.00"; this.txtUnitPrice6.Focus(); } try { quantity6 = int.Parse(this.txtQuantity6.Text); } catch(FormatException ) { MessageBox.Show("Invalid Quantity"); this.txtQuantity6.Text = "0"; this.txtQuantity6.Focus(); } item1SubTotal = item1UnitPrice * quantity1; item2SubTotal = item2UnitPrice * quantity2; item3SubTotal = item3UnitPrice * quantity3; item4SubTotal = item4UnitPrice * quantity4; item5SubTotal = item5UnitPrice * quantity5; item6SubTotal = item6UnitPrice * quantity6; totalOrder = item1SubTotal + item2SubTotal + item3SubTotal + item4SubTotal + item5SubTotal + item6SubTotal; this.txtSubTotal1.Text = item1SubTotal.ToString("F"); this.txtSubTotal2.Text = item2SubTotal.ToString("F"); this.txtSubTotal3.Text = item3SubTotal.ToString("F"); this.txtSubTotal4.Text = item4SubTotal.ToString("F"); this.txtSubTotal5.Text = item5SubTotal.ToString("F"); this.txtSubTotal6.Text = item6SubTotal.ToString("F"); this.txtTotalOrder.Text = totalOrder.ToString("F"); }

24. Display the first form (Form1.cs [Design]) and design it as follows:
     

    Control Name Text Button btnNewItem New Store Item Button btnNewOrder New Purchase Order Button btnClose Close

25. Double-click the New Store Item button and implement its event as follows:
     

    private void btnNewItem_Click(object sender, System.EventArgs e) { NewStoreItem frm = new NewStoreItem(); frm.ShowDialog(); }

26. Return to the form. Double-click the New Purchase Order and implement its event as follows:
     

    private void btnNewOrder_Click(object sender, System.EventArgs e) { PurchaseOrder frm = new PurchaseOrder(); frm.ShowDialog(); }

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

    private void btnClose_Click(object sender, System.EventArgs e) { Close(); }

28. Save all

Application Data Entry

To perform data entry, we will apply the concepts reviewed for data records.

Practical Learning: Introducing Data Entry

Saving the Items and the Orders

Based on the close relationship between the DataSet class and XML, we will save our records as XML.

Practical Learning: Opening an XML File