OleDbCommand 构造函数

定义

初始化 OleDbCommand 类的新实例。

重载

OleDbCommand()

初始化 OleDbCommand 类的新实例。

OleDbCommand(String)

使用查询的文本初始化 OleDbCommand 类的新实例。

OleDbCommand(String, OleDbConnection)

使用查询的文本和 OleDbConnection 初始化 OleDbCommand 类的新实例。

OleDbCommand(String, OleDbConnection, OleDbTransaction)

使用查询文本、OleDbConnection 以及 Transaction 初始化 OleDbCommand 类的新实例。

OleDbCommand()

Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs

初始化 OleDbCommand 类的新实例。

public:
 OleDbCommand();
public OleDbCommand ();
Public Sub New ()

示例

以下示例创建 并 OleDbCommand 设置其一些属性。

public void CreateReader(string connectionString, string queryString)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        OleDbCommand command = new OleDbCommand(queryString, connection);
        command.CommandTimeout = 20;

        connection.Open();
        OleDbDataReader reader = command.ExecuteReader();

        while (reader.Read())
        {
            Console.WriteLine(reader[0].ToString());
        }
        reader.Close();
    }
}
Public Sub CreateReader(ByVal connectionString As String, _
    ByVal queryString As String)

    Using connection As New OleDbConnection(connectionString)
        Dim command As New OleDbCommand(queryString, connection)
        command.CommandTimeout = 20

        connection.Open()

        Dim reader As OleDbDataReader = command.ExecuteReader()
        While reader.Read()
            Console.WriteLine(reader(0).ToString())
        End While
        reader.Close()
    End Using
End Sub

注解

基构造函数将所有字段初始化为其默认值。 下表显示了 实例 OleDbCommand的初始属性值。

属性 初始值
CommandText 空字符串 (“”)
CommandTimeout 30
CommandType Text
Connection null

另请参阅

适用于

OleDbCommand(String)

Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs

使用查询的文本初始化 OleDbCommand 类的新实例。

public:
 OleDbCommand(System::String ^ cmdText);
public OleDbCommand (string? cmdText);
public OleDbCommand (string cmdText);
new System.Data.OleDb.OleDbCommand : string -> System.Data.OleDb.OleDbCommand
Public Sub New (cmdText As String)

参数

cmdText
String

查询的文本。

示例

以下示例创建 并 OleDbCommand 设置其一些属性。

public void CreateMyOleDbCommand()
{
   string queryString = "SELECT * FROM Categories ORDER BY CategoryID";
   OleDbCommand command = new OleDbCommand(queryString);
   command.CommandTimeout = 20;
}
Public Sub CreateMyOleDbCommand()
    Dim queryString As String = "SELECT * FROM Categories ORDER BY CategoryID"
    Dim command As New OleDbCommand(queryString)
    command.CommandTimeout = 20
End Sub

注解

下表显示了 实例 OleDbCommand的初始属性值。

属性 初始值
CommandText cmdText
CommandTimeout 30
CommandType Text
Connection null

另请参阅

适用于

OleDbCommand(String, OleDbConnection)

Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs

使用查询的文本和 OleDbConnection 初始化 OleDbCommand 类的新实例。

public:
 OleDbCommand(System::String ^ cmdText, System::Data::OleDb::OleDbConnection ^ connection);
public OleDbCommand (string? cmdText, System.Data.OleDb.OleDbConnection? connection);
public OleDbCommand (string cmdText, System.Data.OleDb.OleDbConnection connection);
new System.Data.OleDb.OleDbCommand : string * System.Data.OleDb.OleDbConnection -> System.Data.OleDb.OleDbCommand
Public Sub New (cmdText As String, connection As OleDbConnection)

参数

cmdText
String

查询的文本。

connection
OleDbConnection

表示到数据源的连接的 OleDbConnection

示例

以下示例创建 并 OleDbCommand 设置其一些属性。

public void CreateReader(string connectionString, string queryString)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        OleDbCommand command = new OleDbCommand(queryString, connection);
        command.CommandTimeout = 20;

        connection.Open();
        OleDbDataReader reader = command.ExecuteReader();

        while (reader.Read())
        {
            Console.WriteLine(reader[0].ToString());
        }
        reader.Close();
    }
}
Public Sub CreateReader(ByVal connectionString As String, _
    ByVal queryString As String)

    Using connection As New OleDbConnection(connectionString)
        Dim command As New OleDbCommand(queryString, connection)
        command.CommandTimeout = 20

        connection.Open()

        Dim reader As OleDbDataReader = command.ExecuteReader()
        While reader.Read()
            Console.WriteLine(reader(0).ToString())
        End While
        reader.Close()
    End Using
End Sub

注解

下表显示了 实例 OleDbCommand的初始属性值。

属性 初始值
CommandText cmdText
CommandTimeout 30
CommandType Text
Connection 一个新的 OleDbConnection ,它是 参数的值 connection

可以通过设置相关属性来更改其中任何参数的值。

另请参阅

适用于

OleDbCommand(String, OleDbConnection, OleDbTransaction)

Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs
Source:
OleDbCommand.cs

使用查询文本、OleDbConnection 以及 Transaction 初始化 OleDbCommand 类的新实例。

public:
 OleDbCommand(System::String ^ cmdText, System::Data::OleDb::OleDbConnection ^ connection, System::Data::OleDb::OleDbTransaction ^ transaction);
public OleDbCommand (string? cmdText, System.Data.OleDb.OleDbConnection? connection, System.Data.OleDb.OleDbTransaction? transaction);
public OleDbCommand (string cmdText, System.Data.OleDb.OleDbConnection connection, System.Data.OleDb.OleDbTransaction transaction);
new System.Data.OleDb.OleDbCommand : string * System.Data.OleDb.OleDbConnection * System.Data.OleDb.OleDbTransaction -> System.Data.OleDb.OleDbCommand
Public Sub New (cmdText As String, connection As OleDbConnection, transaction As OleDbTransaction)

参数

cmdText
String

查询的文本。

connection
OleDbConnection

表示到数据源的连接的 OleDbConnection

transaction
OleDbTransaction

OleDbCommand 在其中执行的事务。

示例

以下示例创建 并 OleDbCommand 设置其一些属性。

public void CreateReader(string connectionString, string queryString)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        OleDbCommand command = new OleDbCommand(queryString, connection);
        command.CommandTimeout = 20;

        connection.Open();
        OleDbDataReader reader = command.ExecuteReader();

        while (reader.Read())
        {
            Console.WriteLine(reader[0].ToString());
        }
        reader.Close();
    }
}
Public Sub CreateReader(ByVal connectionString As String, _
    ByVal queryString As String)

    Using connection As New OleDbConnection(connectionString)
        Dim command As New OleDbCommand(queryString, connection)
        command.CommandTimeout = 20

        connection.Open()

        Dim reader As OleDbDataReader = command.ExecuteReader()
        While reader.Read()
            Console.WriteLine(reader(0).ToString())
        End While
        reader.Close()
    End Using
End Sub

注解

下表显示了 实例 OleDbCommand的初始属性值。

属性 初始值
CommandText cmdText
CommandTimeout 30
CommandType Text
Connection 一个新的 OleDbConnection ,它是 参数的值 connection

可以通过设置相关属性来更改其中任何参数的值。

另请参阅

适用于