SqlCommand.ExecuteScalarAsync Method (CancellationToken)
An asynchronous version of ExecuteScalar, which executes the query asynchronously and returns the first column of the first row in the result set returned by the query. Additional columns or rows are ignored.
The cancellation token can be used to request that the operation be abandoned before the command timeout elapses. Exceptions will be reported via the returned Task object.
Assembly: System.Data (in System.Data.dll)
Calling ExecuteScalarAsync more than once for the same instance before task completion.
Context Connection=true is specified in the connection string.
SQL Server returned an error while executing the command text.
A timeout occurred during a streaming operation. For more information about streaming, see SqlClient Streaming Support.
For more information about asynchronous programming in the .NET Framework Data Provider for SQL Server, see Asynchronous Programming.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.