SqlCeCommand.ExecuteReader Method (CommandBehavior)

Článek
03/29/2011

Sends the CommandText to the Connection and builds a SqlCeDataReader by using one of the CommandBehavior values.

Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)

Syntax

'Declaration
Public Function ExecuteReader ( _
    behavior As CommandBehavior _
) As SqlCeDataReader
'Usage
Dim instance As SqlCeCommand
Dim behavior As CommandBehavior
Dim returnValue As SqlCeDataReader

returnValue = instance.ExecuteReader(behavior)

public SqlCeDataReader ExecuteReader(
    CommandBehavior behavior
)

public:
SqlCeDataReader^ ExecuteReader(
    CommandBehavior behavior
)

member ExecuteReader : 
        behavior:CommandBehavior -> SqlCeDataReader

public function ExecuteReader(
    behavior : CommandBehavior
) : SqlCeDataReader

Parameters

behavior
Type: System.Data.CommandBehavior
One of the CommandBehavior values.

Return Value

Type: System.Data.SqlServerCe.SqlCeDataReader
A SqlCeDataReader object.

Exceptions

Exception	Condition
InvalidOperationException	Cannot execute a command within a transaction context that differs from the context in which the connection was originally enlisted.

Remarks

The SqlCeDataReader supports a special mode that enables large binary values to be read efficiently. For more information, see the SequentialAccess setting for CommandBehavior.

While the SqlCeDataReader is in use, the associated SqlCeConnection is busy serving the SqlCeDataReader. In this state, until you call the Close method of the SqlCeDataReader, you can perform only the Close operation on the SqlCeConnection.

Examples

The following example creates a SqlCeCommand, and then executes it by passing an SQL SELECT statement and a SqlCeConnection object. CommandBehavior is set to CloseConnection.

Dim conn As New SqlCeConnection(connString)
Dim cmd As New SqlCeCommand("SELECT * FROM myTable", conn)

cmd.Connection.Open()
Dim rdr As SqlCeDataReader = Nothing

Try
    ' Execute the reader; make sure you alway close the 
    ' reader after you're done using it (ideally in the finally block)
    '
    rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)

    While rdr.Read()
        Console.WriteLine(rdr.GetString(0))
    End While
Finally
    ' Closing the reader will also close the associated connection
    '
    rdr.Close()
End Try

SqlCeConnection conn = new SqlCeConnection(connString);
SqlCeCommand cmd = new SqlCeCommand("SELECT * FROM myTable", conn);

cmd.Connection.Open();
SqlCeDataReader rdr = null;

try
{
    // Execute the reader; make sure you alway close the 
    // reader after you're done using it (ideally in the finally block)
    //
    rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

    while (rdr.Read())
    {
        Console.WriteLine(rdr.GetString(0));
    }
}
finally
{
    // Closing the reader will also close the associated connection
    //
    rdr.Close();
}

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