Lightstreamer PCL (Portable Class Library) Client 3.1.0
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IUpdateInfo.GetOldValue Method (int)

Gets the value for a field as it was before the reception of this update. If the current update is the first one, then all old values are null. 

If the "COMMAND logic" behaviour is enabled, then the value is meant as relative to the same key; as a consequence, on ADD commands all old values are null. 

 

C++
string GetOldValue(int fieldPos);
C#
string GetOldValue(int fieldPos);
Visual Basic
Function GetOldValue(fieldPos As Integer) As string
Parameters 
Description 
int fieldPos 
a 1-based field position within the Schema of fields in the related table. 

the previous field value, according to the above specifications; null is a legal value too.

Exceptions 
Description 
ArgumentException 
the specified field position does not represent a subscribed field.