Read-, ReadText-, Write- und WriteText-Methode – Beispiel (VB)

In diesem Beispiel wird veranschaulicht, wie der Inhalt eines Textfelds sowohl in einem Textstream als auch in einem Binärstream gelesen wird. Zu den angezeigten Eigenschaften und Methoden gehören Position, Size, Charset und SetEOS.

'BeginReadVB  
Private Sub cmdRead_Click()  
    On Error GoTo ErrorHandler  
  
    'Declare variables  
    Dim objStream As Stream  
    Dim varA As Variant  
    Dim bytA() As Byte  
    Dim i As Integer  
    Dim strBytes As String  
  
    'Instantiate and Open Stream  
    Set objStream = New Stream  
    objStream.Open  
  
    'Write the text content of a textbox to the stream  
    If Text1.Text = "" Then  
        Err.Raise 1, , "The text field is blank."  
    End If  
    objStream.WriteText Text1.Text  
  
    'Display the text contents and size of the stream  
    objStream.Position = 0  
    Debug.Print "Default text:"  
    Debug.Print objStream.ReadText  
    Debug.Print objStream.Size  
  
    'Switch character set and display  
    objStream.Position = 0  
    objStream.Charset = "Windows-1252"  
    Debug.Print "New Charset text:"  
    Debug.Print objStream.ReadText  
    Debug.Print objStream.Size  
  
    'Switch to a binary stream and display  
    objStream.Position = 0  
    objStream.Type = adTypeBinary  
    Debug.Print "Binary:"  
    Debug.Print objStream.Read  
    Debug.Print objStream.Size  
  
    'Load an array of bytes with the text box text  
    ReDim bytA(Len(Text1.Text))  
    For i = 1 To Len(Text1.Text)  
        bytA(i - 1) = CByte(Asc(Mid(Text1.Text, i, 1)))  
    Next  
  
    'Write the buffer to the binary stream and display  
    objStream.Position = 0  
    objStream.Write bytA()  
    objStream.SetEOS  
    objStream.Position = 0  
    Debug.Print "Binary after Write:"  
    Debug.Print objStream.Read  
    Debug.Print objStream.Size  
  
    'Switch back to a text stream and display  
    Debug.Print "Translated back:"  
    objStream.Position = 0  
    objStream.Type = adTypeText  
    Debug.Print objStream.ReadText  
    Debug.Print objStream.Size  
  
    ' clean up  
    objStream.Close  
    Set objStream = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not objStream Is Nothing Then  
        If objStream.State = adStateOpen Then objStream.Close  
    End If  
    Set objStream = Nothing  
  
    If Err <> 0 Then  
        MsgBox Err.Source & "-->" & Err.Description, , "Error"  
    End If  
End Sub  
'EndReadVB  

Weitere Informationen

Charset-Eigenschaft (ADO)
Position-Eigenschaft (ADO)
Read-Methode
ReadText-Methode
SetEOS-Methode
Size-Eigenschaft (ADO-Stream)
Stream-Objekt (ADO)
Write-Methode
WriteText-Methode