Read、ReadText、Write、WriteText メソッドの例 (VB)

この例では、テキスト ボックスの内容をテキスト Stream とバイナリ Stream の両方に読み込む方法について説明します。 説明する他のプロパティとメソッドは、Position、Size、Charset、SetEOS などです。

'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  

参照

Charset プロパティ (ADO)
Position プロパティ (ADO)
Read メソッド
ReadText メソッド
SetEOS メソッド
Size プロパティ (ADO Stream)
Stream オブジェクト (ADO)
Write メソッド
WriteText メソッド