Session.ExecuteScalarAsync(String, QueryParameterCollection, CancellationToken) Method

Asynchronously executes the specified SQL query and returns the first column of the first row in the result set returned by the query.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v21.1.dll

NuGet Package: DevExpress.Xpo

Declaration

C#

public Task<object> ExecuteScalarAsync(
    string sql,
    QueryParameterCollection parameters,
    CancellationToken cancellationToken = default(CancellationToken)
)

VB.NET

Public Function ExecuteScalarAsync(
    sql As String,
    parameters As QueryParameterCollection,
    cancellationToken As CancellationToken = Nothing
) As Task(Of Object)

Parameters

Name	Type	Description
sql	String	Specifies an SQL statement.
parameters	QueryParameterCollection	Specifies query parameter values.

Optional Parameters

Name	Type	Default	Description
cancellationToken	CancellationToken	*null*	A CancellationToken object that delivers a cancellation notice to the running operation.

Returns

Type	Description
Task<Object>	A Task<TResult> that returns the first column of the first row in the query’s result set. A null reference (Nothing in Visual Basic) if the result set does not contain columns. DBNull.Value if the first column does not contain a value.

Remarks

Use the ExecuteScalarAsync method to query data stores for a single or aggregate value, without having to retrieve a result set.

Use QueryParameterCollection to pass strongly-typed parameters. See examples here: Always Encrypted (SQL Server only).

The connection provider automatically generates sequential parameter names (p0, p1, p2 …). To specify custom parameter names, use the overloaded ExecuteScalarAsync(String, String[], QueryParameterCollection, CancellationToken) method.

To learn more about executing SQL statements in XPO, refer to Direct SQL Queries.

Note

The ExecuteScalarAsync method sends statements directly, so the correct statement syntax and parameter names format depends on a particular database server.