SqlCeDataReader.Read 方法

将 SqlCeDataReader 移到下一个记录。

命名空间：  System.Data.SqlServerCe
程序集：  System.Data.SqlServerCe（在 System.Data.SqlServerCe.dll 中）

语法

声明
Public Overrides Function Read As Boolean
用法
Dim instance As SqlCeDataReader
Dim returnValue As Boolean

returnValue = instance.Read()

public override bool Read()

public:
virtual bool Read() override

abstract Read : unit -> bool 
override Read : unit -> bool 

public override function Read() : boolean

返回值

类型：System.Boolean
如果存在多个行，则为 true；否则为 false。

实现

IDataReader.Read()

注释

SqlCeDataReader 的默认位置在第一条记录前面。若要开始访问数据，必须先调用 Read。SqlCeResultSet 的默认位置在第一条记录。在创建 SqlCeResultSet 之后立即调用 SqlCeResultSet.Read 方法会将游标移至第二条记录。SqlCeDataReader.Read 的行为不同于 SqlCeResultSet.Read 的行为。

在使用 SqlCeDataReader 时，相关联的 SqlCeConnection 正忙于为它服务，直到调用 Close 才停止。

示例

下面的示例创建一个 SqlCeConnection、一个 SqlCeCommand 和一个 SqlCeDataReader。该示例读取全部数据，并将数据写到控制台。最后，该示例先关闭 SqlCeDataReader，然后关闭 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();
}

请参阅

参考

SqlCeDataReader 类

System.Data.SqlServerCe 命名空间