SqlCeResultSet.ReadRelative 方法
按指定的距离从当前位置移动阅读器。
命名空间: System.Data.SqlServerCe
程序集: System.Data.SqlServerCe(在 system.data.sqlserverce.dll 中)
语法
声明
Public Function ReadRelative ( _
position As Integer _
) As Boolean
用法
Dim instance As SqlCeResultSet
Dim position As Integer
Dim returnValue As Boolean
returnValue = instance.ReadRelative(position)
public bool ReadRelative (
int position
)
public:
bool ReadRelative (
int position
)
public boolean ReadRelative (
int position
)
public function ReadRelative (
position : int
) : boolean
不适用。
参数
- position
阅读器要移动的位置数。
返回值
如果操作成功,则为 true;否则为 false。
备注
如果您传递的位置数是一个正整数,则此函数在结果集中向前移动阅读器。如果您传递的位置数是一个负整数,则此函数在结果集中向后移动阅读器。
示例
下面的示例创建一个 ResultSet 对象,然后调用包括 ReadRelative 在内的多个方法。
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();
}
平台
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
Windows Vista、Microsoft Windows XP SP2 和 Windows Server 2003 SP1 支持 Microsoft .NET Framework 3.0。
版本信息
.NET Framework
受以下版本支持:3.0
.NET Compact Framework
受以下版本支持:2.0
请参见
参考
SqlCeResultSet 类
SqlCeResultSet 成员
System.Data.SqlServerCe 命名空间