[VB.NET] XML กับอัตราการแลกเปลี่ยนเงินตราเทียบกับสกุลเงินยูโร

thongkorn

โค้ดชุดนี้เป็นการคำนวณอัตราการแลกเปลี่ยนเงินตราเทียบกับสกุลเงินยูโรจาก European Central Bank (ECB) โค้ดจะทำการแยกแยะข้อมูล (Parser) ออกจากเอกสาร XML แล้วทำการจับคู่ (Pair) สกุลเงินกับอัตราแลกเปลี่ยน (2 Attribute) เพื่อนำไปคำนวณหาอัตราแลกเปลี่ยนระหว่างสกุลเงิน เช่น US Dollar มาเป็น Thai Baht ...

มาดูโค้ดกันเถอะ ...

1. Public Class frmExchangeCurrency
   
2. 
   
3.     '// Match the currency with the rate.
   
4.     '// From XML (eXtensible Markup Language)
   
5.     '// <Cube currency="USD" rate="1.0963"/>
   
6.     Private ReadOnly ExchangeRate As Dictionary(Of String, Decimal) = New Dictionary(Of String, Decimal)()
   
7. 
   
8.     Private Sub frmExchangeCurrency_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
   
9.         With Amount
   
10.             .DecimalPlaces = 2
    
11.             .ThousandsSeparator = True
    
12.         End With
    
13.         With cmbFrom
    
14.             .IntegralHeight = False
    
15.             .MaxDropDownItems = 10
    
16.         End With
    
17.         With cmbTo
    
18.             .IntegralHeight = False
    
19.             .MaxDropDownItems = 10
    
20.         End With
    
21.         lblUpDate.Text = ""
    
22.         lblExchange.Text = ""
    
23.     End Sub
    
24. 
    
25.     Private Sub btnParser_Click(sender As System.Object, e As System.EventArgs) Handles btnParser.Click
    
26.         lblExchange.Text = ""
    
27.         Call InitialListView()
    
28.         Call LoadCurrency()
    
29.     End Sub
    
30. 
    
31.     '// Initialize ListView Control
    
32.     Sub InitialListView()
    
33.         ExchangeRate.Clear()
    
34.         With lvwRate
    
35.             .Clear()
    
36.             .View = View.Details
    
37.             .GridLines = True
    
38.             .FullRowSelect = True
    
39.             .HideSelection = False
    
40.             .MultiSelect = False
    
41.             .Columns.Add("Currency", lvwRate.Width \ 2)
    
42.             .Columns.Add("Rate", lvwRate.Width \ 2 - 20)
    
43.         End With
    
44.     End Sub
    
45. 
    
46.     '// XML Parser.
    
47.     Private Sub LoadCurrency()
    
48.         '// Sample XML Format.
    
49.         '<Cube>
    
50.         '<Cube time="2023-04-10">
    
51.         '<Cube currency="USD" rate="1.0963"/>
    
52.         '<Cube currency="JPY" rate="117.66"/>
    
53.         '<Cube currency="BGN" rate="1.9558"/>
    
54.         '<Cube currency="CZK" rate="26.864"/>
    
55.         '<Cube currency="DKK" rate="7.4623"/>
    
56.         '<Cube currency="GBP" rate="0.87253"/>
    
57.         '<Cube currency="HUF" rate="350.70"/>
    
58.         '<Cube currency="PLN" rate="4.5473"/>
    
59.         '<Cube currency="RON" rate="4.8343"/>
    
60.         '<Cube currency="SEK" rate="10.9158"/>
    
61.         '<Cube currency="CHF" rate="1.0543"/>
    
62.         '<Cube currency="ISK" rate="155.90"/>
    
63.         '<Cube currency="NOK" rate="11.3118"/>
    
64.         '<Cube currency="HRK" rate="7.6130"/>
    
65.         '<Cube currency="RUB" rate="80.3923"/>
    
66.         '<Cube currency="TRY" rate="7.4472"/>
    
67.         '<Cube currency="AUD" rate="1.7139"/>
    
68.         '<Cube currency="BRL" rate="5.6585"/>
    
69.         '<Cube currency="CAD" rate="1.5257"/>
    
70.         '<Cube currency="CNY" rate="7.7366"/>
    
71.         '<Cube currency="HKD" rate="8.4975"/>
    
72.         '<Cube currency="IDR" rate="17229.09"/>
    
73.         '<Cube currency="ILS" rate="3.9280"/>
    
74.         '<Cube currency="INR" rate="83.4940"/>
    
75.         '<Cube currency="KRW" rate="1332.53"/>
    
76.         '<Cube currency="MXN" rate="25.8485"/>
    
77.         '<Cube currency="MYR" rate="4.7508"/>
    
78.         '<Cube currency="NZD" rate="1.8008"/>
    
79.         '<Cube currency="PHP" rate="55.453"/>
    
80.         '<Cube currency="SGD" rate="1.5521"/>
    
81.         '<Cube currency="THB" rate="35.860"/>
    
82.         '<Cube currency="ZAR" rate="20.0255"/>
    
83.         '</Cube>
    
84.         '</Cube>
    
85.         Try
    
86.             '// Provide Security in VS2010 and .Net Framework lower than 4.5
    
87.             System.Net.ServicePointManager.SecurityProtocol = DirectCast(3072, System.Net.SecurityProtocolType)
    
88.             Dim xmlDoc As New XmlDocument()
    
89.             xmlDoc.Load("http://www.ecb.int/stats/eurofxref/eurofxref-daily.xml")
    
90.             '// Update
    
91.             '<Cube time="2023-04-21">
    
92.             lblUpDate.Text = "Rates Updated: " & xmlDoc.DocumentElement.ChildNodes(2).ChildNodes(0).Attributes("time").Value.ToString
    
93.             For Each node As XmlNode In xmlDoc.DocumentElement.ChildNodes(2).ChildNodes(0).ChildNodes
    
94.                 '// Match currency and exchange rates.
    
95.                 '// <Cube currency="USD" rate="1.0963"/>
    
96.                 ExchangeRate.Add(node.Attributes("currency").Value, Decimal.Parse(node.Attributes("rate").Value))
    
97.                 Dim LV As ListViewItem
    
98.                 LV = lvwRate.Items.Add(node.Attributes("currency").Value)   '// Create main node.
    
99.                 LV.SubItems.Add(node.Attributes("rate").Value)
    
100.                 '// Add to ComboBox.
     
101.                 cmbFrom.Items.Add(node.Attributes("currency").Value)
     
102.                 cmbTo.Items.Add(node.Attributes("currency").Value)
     
103.             Next
     
104.             '// Sorting ListView from A to Z (Ascending)
     
105.             Me.lvwRate.Sorting = SortOrder.Ascending
     
106.             cmbFrom.SelectedIndex = 0
     
107.             cmbTo.SelectedIndex = 0
     
108. 
     
109.         Catch ex As Exception
     
110.             MessageBox.Show(ex.Message, "Read Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
     
111.         End Try
     
112.     End Sub
     
113. 
     
114.     Private Sub btnExchange_Click(sender As System.Object, e As System.EventArgs) Handles btnExchange.Click
     
115.         If cmbFrom.Items.Count = 0 AndAlso cmbTo.Items.Count = 0 Then Return
     
116.         '// Get pair value from ExchangeRate.
     
117.         Dim ExchangeCurrency As Double = (Amount.Value / ExchangeRate(cmbFrom.Text)) * ExchangeRate(cmbTo.Text)
     
118.         lblExchange.Text = Amount.Value & " " & cmbFrom.Text & " = " & ExchangeCurrency.ToString("#,##0.00") & " " & cmbTo.Text
     
119.     End Sub
     
120. 
     
121.     Private Sub btnExit_Click(sender As System.Object, e As System.EventArgs) Handles btnExit.Click
     
122.         Me.Close()
     
123.     End Sub
     
124. 
     
125.     Private Sub frmExchangeCurrency_FormClosed(sender As Object, e As System.Windows.Forms.FormClosedEventArgs) Handles Me.FormClosed
     
126.         Me.Dispose()
     
127.         GC.SuppressFinalize(Me)
     
128.         Application.Exit()
     
129.     End Sub
     
130. 
     
131. End Class

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