CanSeek Property

In This Topic

Gets a value indicating whether forward and backward seek operations can be performed.

Syntax

Visual Basic
C#

'Declaration
 
Public Overrides ReadOnly Property CanSeek As Boolean

public override bool CanSeek {get;}

Property Value

true if the SQLiteBlob stream supports seeking; false if a SQLiteBlob is closed, disposed, or Null.

Remarks

Use this property to find out if a SQLiteBlob supports Seek operation. SQLiteBlob does not support seeking if it has Null value as well as if it has been disposed or closed.

Example

csharp

void ReverseBlob()
{
  byte[] byteArray = { (byte)'A', (byte)'B', (byte)'C' };
  SQLiteBlob blobFrom = new SQLiteBlob(byteArray);
  //blobFrom.ToString() = "ABC"

  SQLiteBlob blobTo = new SQLiteBlob();
  ........
  //reverse SQLiteBlob
  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";
}

Visual Basic

Private Sub ReverseBlob()
  Dim byteArray As Byte() = New Byte() {AscW("A"c), AscW("B"c), AscW("C"c)}
  Dim blobFrom As New SQLiteBlob(byteArray)
  ' blobFrom.ToString() = "ABC"

  Dim blobTo As New SQLiteBlob
  ......
  ' reverse SQLiteBlob
  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

Reference

SQLiteBlob Class
SQLiteBlob Members

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