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Devart.Data.Oracle Namespace / OracleLob Class / CanSeek Property
Example

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    CanSeek Property
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    Gets a value indicating whether forward and backward seek operations can be performed.
    Syntax
    'Declaration
     
    Public Overrides ReadOnly Property CanSeek As Boolean
    public override bool CanSeek {get;}

    Property Value

    true if the OracleLob stream supports seeking; false if a OracleLob is closed, disposed, or Null.
    Remarks
    Use this property to find out if a OracleLob supports Seek operation. OracleLob does not support seeking if it has Null value as well as if it has been disposed or closed.
    Example
    static void ReverseBlob() 
    { 
            byte[] byteArray = { (byte)'A', (byte)'B', (byte)'C' }; 
            OracleLob blobFrom = new OracleLob(OracleDbType.Blob);
            blobFrom.Write(byteArray, 0, byteArray.Length);
            //blobFrom.ToString() = "ABC" 
    
            OracleLob blobTo = new OracleLob(OracleDbType.Blob); 
            ........
            //reverse OracleLob 
            if (blobFrom.CanSeek && blobFrom.CanRead && blobTo.CanWrite) 
                    for (blobFrom.Seek(-1, System.IO.SeekOrigin.End); ;blobFrom.Position -= 2) 
                    { 
                            blobTo.WriteByte((byte)blobFrom.ReadByte()); 
                            if (blobFrom.Position == 1) break; 
                    } 
            //blobTo.ToString() = "CBA"; 
    }
    Private Sub ReverseBlob()
            Dim byteArray As Byte() = New Byte() {AscW("A"c), AscW("B"c), AscW("C"c)}
            Dim blobFrom As New OracleLob(OracleDbType.Blob)
            blobFrom.Write(byteArray, 0, byteArray.Length)
            ' blobFrom.ToString() = "ABC"
    
            Dim blobTo As New OracleLob(OracleDbType.Blob)
            ........
            ' reverse OracleLob
            If ((blobFrom.CanSeek AndAlso blobFrom.CanRead) AndAlso blobTo.CanWrite) Then
                    blobFrom.Seek(CLng(-1), System.IO.SeekOrigin.End)
                    Do While True
                            blobTo.WriteByte(CByte(blobFrom.ReadByte))
                            If (blobFrom.Position = 1) Then
                                    Return
                            End If
                            blobFrom.Position = blobFrom.Position - 2
                    Loop
            End If
            ' blobTo.ToString() = "CBA";
    End Sub
    Requirements

    Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

    See Also