SqlCeDataReader Class
Provides a way of reading a forward-only stream of data rows from a data source. This class cannot be inherited.
Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)
Syntax
'Declaration
Public Class SqlCeDataReader _
Inherits DbDataReader
'Usage
Dim instance As SqlCeDataReader
public class SqlCeDataReader : DbDataReader
public ref class SqlCeDataReader : public DbDataReader
type SqlCeDataReader =
class
inherit DbDataReader
end
public class SqlCeDataReader extends DbDataReader
Remarks
To create a SqlCeDataReader, you must call the ExecuteReader method of the SqlCeCommand object, rather than directly using a constructor.
While the SqlCeDataReader is in use, the associated SqlCeConnection is busy serving the SqlCeDataReader. In this state, you can create multiple readers in the same connection.
Changes made to a result set by another process or thread while the data is being read may be visible to the user of the SqlCeDataReader; however, the precise behavior is dependent on when these occur.
IsClosed and RecordsAffected are the only properties you can call after the SqlCeDataReader is closed. Although the RecordsAffected property can be accessed at any time while the SqlCeDataReader exists, always call Close before returning the value of RecordsAffected to ensure an accurate return value.
Examples
The following example creates a SqlCeConnection, a SqlCeCommand, and a SqlCeDataReader. The example reads through the data and writes it out to the console, and then closes the SqlCeDataReader and the SqlCeConnection.
Dim conn As SqlCeConnection = Nothing
Dim cmd As SqlCeCommand = Nothing
Dim rdr As SqlCeDataReader = Nothing
Try
' Open the connection and create a SQL command
'
conn = New SqlCeConnection("Data Source = AdventureWorks.sdf")
conn.Open()
cmd = New SqlCeCommand("SELECT * FROM DimEmployee", conn)
rdr = cmd.ExecuteReader()
' Iterate through the results
'
While rdr.Read()
Dim employeeID As Integer = rdr.GetInt32(0) ' or: rdr["EmployeeKey"];
Dim lastName As String = rdr.GetString(5) ' or: rdr["FirstName"];
End While
' Always dispose data readers and commands as soon as practicable
'
rdr.Close()
cmd.Dispose()
Finally
' Close the connection when no longer needed
'
conn.Close()
End Try
SqlCeConnection conn = null;
SqlCeCommand cmd = null;
SqlCeDataReader rdr = null;
try
{
// Open the connection and create a SQL command
//
conn = new SqlCeConnection("Data Source = AdventureWorks.sdf");
conn.Open();
cmd = new SqlCeCommand("SELECT * FROM DimEmployee", conn);
rdr = cmd.ExecuteReader();
// Iterate through the results
//
while (rdr.Read())
{
int employeeID = rdr.GetInt32(0); // or: rdr["EmployeeKey"];
string lastName = rdr.GetString(5); // or: rdr["FirstName"];
}
// Always dispose data readers and commands as soon as practicable
//
rdr.Close();
cmd.Dispose();
}
finally
{
// Close the connection when no longer needed
//
conn.Close();
}
Inheritance Hierarchy
System. . :: . .Object
System. . :: . .MarshalByRefObject
System.Data.Common. . :: . .DbDataReader
System.Data.SqlServerCe..::..SqlCeDataReader
System.Data.SqlServerCe. . :: . .SqlCeResultSet
Thread Safety
Any public static (Shared in Microsoft Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.