SqlCeResultSet.ReadLast 方法

将阅读器放在 ResultSet 中的最后一条记录处。

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 ReadLast As Boolean
用法
Dim instance As SqlCeResultSet
Dim returnValue As Boolean

returnValue = instance.ReadLast()

public bool ReadLast()

public:
bool ReadLast()

member ReadLast : unit -> bool 

public function ReadLast() : boolean

返回值

类型：System.Boolean
如果操作成功，则为 true；否则为 false。

示例

下面的示例创建一个 ResultSet 对象，然后调用包括 ReadLast 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();
}

请参阅

参考

SqlCeResultSet 类

System.Data.SqlServerCe 命名空间