SqlCeDataReader Class

Article
10/22/2007

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

public class SqlCeDataReader extends DbDataReader

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.

Example

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 Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Platforms

Windows CE, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows XP Professional x64 Edition, Windows XP SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

Version Information

.NET Compact Framework

Supported in: 2.0, 1.0

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