SqlCeResultSet.ReadAbsolute Method
Moves the reader to a specific record in the ResultSet.
Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)
Syntax
'Declaration
Public Function ReadAbsolute ( _
position As Integer _
) As Boolean
'Usage
Dim instance As SqlCeResultSet
Dim position As Integer
Dim returnValue As Boolean
returnValue = instance.ReadAbsolute(position)
public bool ReadAbsolute(
int position
)
public:
bool ReadAbsolute(
int position
)
member ReadAbsolute :
position:int -> bool
public function ReadAbsolute(
position : int
) : boolean
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.
Remarks
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.
Examples
The following example creates a ResultSet object and then calls several methods, including ReadAbsolute.
Dim conn As SqlCeConnection = Nothing
Try
File.Delete("Test.sdf")
Dim engine As New SqlCeEngine("Data Source = Test.sdf")
engine.CreateDatabase()
conn = New SqlCeConnection("Data Source = Test.sdf")
conn.Open()
Dim cmd As SqlCeCommand = conn.CreateCommand()
cmd.CommandText = "CREATE TABLE myTable (col1 INT)"
cmd.ExecuteNonQuery()
cmd.CommandText = "SELECT * FROM myTable"
Dim rs As SqlCeResultSet = cmd.ExecuteResultSet(ResultSetOptions.Updatable Or ResultSetOptions.Scrollable)
Dim rec As SqlCeUpdatableRecord = rs.CreateRecord()
' Insert 10 records
'
Dim i As Integer
For i = 0 To 9
rec.SetInt32(0, i)
rs.Insert(rec)
Next i
' Scroll through the results
'
If True = rs.ReadFirst() Then
MessageBox.Show("col1 = " & rs.GetInt32(0)) 'ordinal
End If
If True = rs.ReadRelative(5) Then
MessageBox.Show("col1 = " & rs.GetInt32(0)) 'ordinal
End If
If True = rs.ReadLast() Then
MessageBox.Show("col1 = " & rs.GetInt32(0)) 'ordinal
End If
If True = rs.ReadPrevious() Then
MessageBox.Show("col1 = " & rs.GetInt32(0)) 'ordinal
End If
If True = rs.ReadAbsolute(5) Then
MessageBox.Show("col1 = " & rs.GetInt32(0)) 'ordinal
End If
Catch e As Exception
MessageBox.Show(e.Message)
Finally
conn.Close()
End Try
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();
}