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SqlCeResultSet.ReadAbsolute Method

Visual Studio 2010

Moves the reader to a specific record in the ResultSet.

Namespace:  System.Data.SqlServerCe
Assembly:  System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)
C#
C++
F#
JScript
VB
Copy 
public bool ReadAbsolute(
	int position
)

Parameters

position
Type: System.Int32
The position to which to move the reader.

Return Value

Type: System.Boolean
True if the operation succeeded; otherwise, false.

ReadAbsolute is 0-based; calling ReadAbsolute(0) will return the first row of the ResultSet.

This method reads the value of the row based on the row position saved by a bookmark. For example, suppose you have a table with 10 rows, and you open two ResultSets: rs1 and rs2. You call ReadAbsolue(5) on rs1 and change the value of this row to -1. The row's position has now changed to the first position in the list of rows, and row 4 is in the 5th position. However, if you now call ReadAbsolute(5) on rs2, a value of -1 is returned. ResultSet rs2 maintains a bookmark to the original 5th row and continues to read that row, despite its position changing.

If you pass a positive integer to this function, the reader is moved from the first record forward the specified number of records. If you pass a negative integer to this function, the reader is moved from the last record back the specified number of records.

The following example creates a ResultSet object and then calls several methods, including ReadAbsolute.

C#
VB
Copy 
SqlCeConnection conn = null;

try
{
    File.Delete("Test.sdf");

    SqlCeEngine engine = new SqlCeEngine("Data Source = Test.sdf");
    engine.CreateDatabase();

    conn = new SqlCeConnection("Data Source = Test.sdf");
    conn.Open();

    SqlCeCommand cmd = conn.CreateCommand();
    cmd.CommandText = "CREATE TABLE myTable (col1 INT)";
    cmd.ExecuteNonQuery();

    cmd.CommandText = "SELECT * FROM myTable";

    SqlCeResultSet rs = cmd.ExecuteResultSet(ResultSetOptions.Updatable | 
        ResultSetOptions.Scrollable);

    SqlCeUpdatableRecord rec = rs.CreateRecord();

    // Insert 10 records
    //
    for (int i = 0; i < 10; i++)
    {
        rec.SetInt32(0, i);
        rs.Insert(rec);
    }

    // Scroll through the results
    //
    if (true == rs.ReadFirst())
    {
        MessageBox.Show("col1 = " + rs.GetInt32(0 /*ordinal*/));
    }

    if (true == rs.ReadRelative(5))
    {
        MessageBox.Show("col1 = " + rs.GetInt32(0 /*ordinal*/));
    }

    if (true == rs.ReadLast())
    {
        MessageBox.Show("col1 = " + rs.GetInt32(0 /*ordinal*/));
    }

    if (true == rs.ReadPrevious())
    {
        MessageBox.Show("col1 = " + rs.GetInt32(0 /*ordinal*/));
    }

    if (true == rs.ReadAbsolute(5))
    {
        MessageBox.Show("col1 = " + rs.GetInt32(0 /*ordinal*/));
    }
}
catch (Exception e)
{
    MessageBox.Show(e.Message);
}
finally
{
    conn.Close();
}
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