SPChangeToken.ToString Method
Returns the serialized string that represents the change token.
Namespace: Microsoft.SharePoint
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Syntax
<SharePointPermissionAttribute(SecurityAction.Demand, ObjectModel := True)> _
Public Overrides Function ToString As String
Dim instance As SPChangeToken
Dim returnValue As String
returnValue = instance.ToString()
[SharePointPermissionAttribute(SecurityAction.Demand, ObjectModel = true)]
public override string ToString()
Return Value
Type: System.String
A string that contains the serialized representation of the change token.
Remarks
You can use this method to serialize a change token before persisting it to permanent storage. To reconstruct the token, pass the serialized string representation to the SPChangeToken(String) constructor.
Examples
The following example consists of two routines, one to serialize a change token and save it on disk, the other to reconstruct a token that has been saved.
Sub SaveChangeToken(ByVal token As SPChangeToken, ByVal fileName As String)
Using fs As FileStream = File.Create(fileName)
' Serialize the token.
Dim bw As BinaryWriter = New BinaryWriter(fs)
Dim s As String = token.ToString()
bw.Write(s)
' Flush and close.
bw.Flush()
bw.Close()
End Using
End Sub
Function GetChangeToken(ByVal fileName As String) As SPChangeToken
Dim token As SPChangeToken = Nothing
' If we have a token, use it.
If File.Exists(fileName) Then
Using fs As FileStream = File.OpenRead(fileName)
Dim br As BinaryReader = New BinaryReader(fs)
Try
Dim s As String = br.ReadString()
' Construct a change token from a serialized string
token = New SPChangeToken(s)
Catch e As EndOfStreamException
' No serialized string, so do nothing.
Finally
br.Close()
End Try
End Using
End If
Return token
End Function
static void SaveChangeToken(SPChangeToken token, string fileName)
{
using (FileStream fs = File.Create(fileName))
{
// Serialize the token.
BinaryWriter bw = new BinaryWriter(fs);
string s = token.ToString();
bw.Write(s);
// Flush and close.
bw.Flush();
bw.Close();
}
}
static SPChangeToken GetChangeToken(string fileName)
{
SPChangeToken token = null;
// If we have a token, use it.
if (File.Exists(fileName))
{
using (FileStream fs = File.OpenRead(fileName))
{
BinaryReader br = new BinaryReader(fs);
try
{
string s = br.ReadString();
// Construct a change token from a serialized string.
token = new SPChangeToken(s);
}
catch (EndOfStreamException e)
{
// No serialized string, so do nothing.
}
finally
{
br.Close();
}
}
}
return token;
}