IDbDataAdapter.SelectCommand 属性

定义

命名空间:

System.Data

程序集:

System.Data.Common.dll

程序集:

System.Data.dll

程序集:

netstandard.dll

获取或设置用于在数据源中选择记录的 SQL 语句。

public:
 property System::Data::IDbCommand ^ SelectCommand { System::Data::IDbCommand ^ get(); void set(System::Data::IDbCommand ^ value); };

public System.Data.IDbCommand? SelectCommand { get; set; }

public System.Data.IDbCommand SelectCommand { get; set; }

member this.SelectCommand : System.Data.IDbCommand with get, set

Public Property SelectCommand As IDbCommand

属性值

IDbCommand

在 IDbCommand 过程中使用的 Update(DataSet)，它从数据源中选择记录以便放入数据集中。

示例

以下示例创建继承 OleDbDataAdapter 类的实例，并设置 SelectCommand 和 InsertCommand 属性。 它假定你已经创建了一个 OleDbConnection 对象。

public static OleDbDataAdapter CreateCustomerAdapter(
    OleDbConnection connection)
{
    OleDbDataAdapter adapter = new OleDbDataAdapter();
    OleDbCommand command;

    // Create the SelectCommand.
    command = new OleDbCommand("SELECT * FROM Customers " +
        "WHERE Country = ? AND City = ?", connection);

    command.Parameters.Add("Country", OleDbType.VarChar, 15);
    command.Parameters.Add("City", OleDbType.VarChar, 15);

    adapter.SelectCommand = command;

    // Create the InsertCommand.
    command = new OleDbCommand(
        "INSERT INTO Customers (CustomerID, CompanyName) " +
        "VALUES (?, ?)", connection);

    command.Parameters.Add(
        "CustomerID", OleDbType.Char, 5, "CustomerID");
    command.Parameters.Add(
        "CompanyName", OleDbType.VarChar, 40, "CompanyName");

    adapter.InsertCommand = command;
    return adapter;
}

Public Shared Function CreateCustomerAdapter( _
    connection As OleDbConnection) As OleDbDataAdapter 

    Dim adapter As New OleDbDataAdapter()
    Dim command As OleDbCommand

    ' Create the SelectCommand.
    command = New OleDbCommand("SELECT * FROM Customers " & _
        "WHERE Country = ? AND City = ?", connection)

    command.Parameters.Add("Country", OleDbType.VarChar, 15)
    command.Parameters.Add("City", OleDbType.VarChar, 15)

    adapter.SelectCommand = command

    ' Create the InsertCommand.
    command = New OleDbCommand( _
        "INSERT INTO Customers (CustomerID, CompanyName) " & _
        "VALUES (?, ?)", connection)

    command.Parameters.Add( _
        "CustomerID", OleDbType.Char, 5, "CustomerID")
    command.Parameters.Add( _
        "CompanyName", OleDbType.VarChar, 40, "CompanyName")

    adapter.InsertCommand = command
    Return adapter
End Function

注解

分配给以前创建的IDbCommand时SelectCommand，IDbCommand不会克隆。 维护 SelectCommand 对以前创建 IDbCommand 对象的引用。

SelectCommand如果未返回任何行，则不会向其中DataSet添加任何表，并且不会引发异常。