JAK: Vyhled�n� a nahrazen� speci�ln�ch znak� v souboru XML pomoc� jazyka Visual Basic.NET

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Zjist�te, zda je po�adov�na zvl�tn� znak nahrazen�

Nen� po�adov�no: Soubory XML v nich� jsou Data na�tena z datab�ze

Po�adov�no: Soubor XML s speci�ln� znaky

Nahrazen� zvl�tn�ch znak�

1. Vytvo�te soubor XML.
2. Vytvo�en� aplikace Visual Basic.NET aplikac� a potom vlo�te k�d.

Vytvo�it soubor XML

<?xml version="1.0" standalone="yes"?>
<Customers>
<Customer>
<CustomerID>BLAUS</CustomerID>
<CompanyName>Blauer See Delikatessen</CompanyName>
<ContactName>Hanna Moos</ContactName>
<Region>test<ing</Region>
</Customer>
<Customer>
<CustomerID>SPLIR</CustomerID>
<CompanyName>Split Rail Beer & Ale</CompanyName>
<ContactName>Art raunschweiger</ContactName>
<Region>WY</Region>
</Customer>
</Customers>
				

Vytvo�te jazyka Visual Basic.NET projektu

1. Vytvo�en� nov�ho jazyka Visual Basic.S͍ Windows aplikace.
2. Pomoc� operace p�eta�en� a p�esun Textov� poledva Tla��tko Ovl�dac� prvky a Objekt DataGrid.
3. Nastavit V�ce��dkov� sleva Vlastnost Textov� pole k PRAVDA.
4. Importujte n�sleduj�c� obory:

   Imports System.Xml
   Imports System.IO
   Imports System.Data.SqlClient
   					

5. Po n�sleduj�c� ��st

   Inherits System.Windows.Forms.Form

   Zkop�rujte a vlo�te n�sleduj�c� p��klad k�du:

    Dim filepath As String = "C:\customers.xml"
   Private Sub ReplaceSpecialChars(ByVal linenumber As Long)
           Dim strm As StreamReader
           Dim strline As String
           Dim strreplace As String
   
           Dim tempfile As String = "C:\temp.xml"
           Try
               FileCopy(filepath, tempfile)
           Catch ex As Exception
               MessageBox.Show(ex.Message)
           End Try
   
           Dim strmwriter As New StreamWriter(filepath)
           strmwriter.AutoFlush = True
   
           strm = New StreamReader(tempfile)
   
   
           Dim i As Long = 0
           While i < linenumber - 1
               strline = strm.ReadLine
               strmwriter.WriteLine(strline)
               i = i + 1
           End While
   
           strline = strm.ReadLine
           Dim lineposition As Int32
           lineposition = InStr(strline, "&")
           If lineposition > 0 Then
               strreplace = "&amp;"
           Else
               lineposition = InStr(2, strline, "<")
               If lineposition > 0 Then
                   strreplace = "<"
               End If
           End If
           strline = Mid(strline, 1, lineposition - 1) + strreplace + Mid(strline, lineposition + 1)
           strmwriter.WriteLine(strline)
   
           strline = strm.ReadToEnd
           strmwriter.WriteLine(strline)
   
           strm.Close()
           strm = Nothing
   
           strmwriter.Flush()
           strmwriter.Close()
           strmwriter = Nothing
   
       End Sub
   
       Public Function LoadXMLDoc() As XmlDocument
           Dim xdoc As XmlDocument
           Dim lnum As Long
           Dim pos As Long
           Dim Newxml As String
           Try
               xdoc = New XmlDocument()
               xdoc.Load(filepath)
           Catch ex As XmlException
               MessageBox.Show(ex.Message)
               lnum = ex.LineNumber
               ReplaceSpecialChars(lnum)
   
               xdoc = LoadXMLDoc()
   
           End Try
           Return (xdoc)
       End Function
   					

6. Zkop�rujte a vlo�te n�sleduj�c� k�d do Klepn�te na tla��tko ud�losti Button1:

   Dim xmldoc As New XmlDocument()
           xmldoc = LoadXMLDoc()
           Dim nextnode As XmlNode
           nextnode = xmldoc.FirstChild.NextSibling
           TextBox1.Text = nextnode.OuterXml
   					

7. Zkop�rujte a vlo�te n�sleduj�c� k�d do Klepn�te na tla��tko ud�losti Button2:

   Dim ds As New DataSet()
           Dim xdoc As New XmlDocument()
           Dim cnNwind As New SqlConnection("Data source=myservername;user id=myuser;Password=mypassword;Initial catalog=Northwind;")
           Dim daCustomers As New SqlDataAdapter("Select customerid,companyname,contactname, region from customers where region='WY'", cnNwind)
           Dim filepath As String
           Try
               daCustomers.Fill(ds, "Customers")
               DataGrid1.DataSource = ds.Tables(0)
               ds.WriteXml("C:\Dataset.xml")
               xdoc.Load("C:\Dataset.xml")
               Dim nextnode As XmlNode
               nextnode = xdoc.FirstChild.NextSibling
               TextBox1.Text = nextnode.OuterXml.ToString
           Catch ex As Exception
               MessageBox.Show(ex.Message)
           End Try
   					

8. Zm�nit n�zev serveru, u�ivatelsk� jm�no a heslo p�ipojen� k serveru se spu�t�nou slu�bou Microsoft SQL Server.
9. Vytvo�te projekt a spus�te jej.
10. Klepn�te na tla��tko Button1.
    
    Jsou v souladu s chybami, kter� obdr��te Popis chyb, kter� jsou vysv�tleny v "po�adov�no: soubor XML s Speci�ln� znaky"��sti. XML data se zobraz� v Textov� pole; ampersand je nahrazen.
11. Klepn�te na tla��tko Button2.
    
    V Objekt DataGrid, Firma obsahuje ampersand a Textov� pole Zobrazuje data XML s

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