ConnectionEnumerator.Current 属性

定义

命名空间:

Microsoft.SqlServer.Dts.Runtime

程序集:

Microsoft.SqlServer.ManagedDTS.dll

从 ConnectionManager 集合中获取当前的 Connections 对象。

public:
 property Microsoft::SqlServer::Dts::Runtime::ConnectionManager ^ Current { Microsoft::SqlServer::Dts::Runtime::ConnectionManager ^ get(); };

public Microsoft.SqlServer.Dts.Runtime.ConnectionManager Current { get; }

member this.Current : Microsoft.SqlServer.Dts.Runtime.ConnectionManager

Public ReadOnly Property Current As ConnectionManager

属性值

ConnectionManager

ConnectionManager 对象。

示例

下面的代码示例创建一个枚举器，然后使用 Current 和 MoveNext 方法在集合上导航。

using System;  
using System.Collections.Generic;  
using System.Text;  
using Microsoft.SqlServer.Dts.Runtime;  

namespace ConnMgr_GetEnum_Current  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            // The package is one of the SSIS Samples.  
            string mySample = @"C:\Program Files\Microsoft SQL Server\100\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx";  
            // Create the application, and load the sample.  
            Application app = new Application();  
            Package pkg = app.LoadPackage(mySample, null);  

            // Get the Connections collection from the package.  
            Connections conns = pkg.Connections;  

            //Create the Enumerator.  
            ConnectionEnumerator myEnumerator = conns.GetEnumerator();  
            Console.WriteLine("The collection contains the following values:");  
            int i = 0;  
            while ((myEnumerator.MoveNext()) && (myEnumerator.Current != null))  
                Console.WriteLine("[{0}] {1}", i++, myEnumerator.Current.Name);  
        }  
    }  
}  

Imports System  
Imports System.Collections.Generic  
Imports System.Text  
Imports Microsoft.SqlServer.Dts.Runtime  

Namespace ConnMgr_GetEnum_Current  
    Class Program  
        Shared  Sub Main(ByVal args() As String)  
            ' The package is one of the SSIS Samples.  
            Dim mySample As String =  "C:\Program Files\Microsoft SQL Server\100\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx"   
            ' Create the application, and load the sample.  
            Dim app As Application =  New Application()   
            Dim pkg As Package =  app.LoadPackage(mySample,Nothing)   

            ' Get the Connections collection from the package.  
            Dim conns As Connections =  pkg.Connections   

            'Create the Enumerator.  
            Dim myEnumerator As ConnectionEnumerator =  conns.GetEnumerator()   
            Console.WriteLine("The collection contains the following values:")  
            Dim i As Integer =  0   
            While (myEnumerator.MoveNext()) &&(myEnumerator.Current <> Nothing)  
            Console.WriteLine("[{0}] {1}",i = Console.WriteLine("[{0}] {1}",i + 1  
            End While  
        End Sub  
    End Class  
End Namespace  

示例输出：

该集合包含以下值：

[0] localhost。AdventureWorks

[1] Product1 的事务摘要

注解

创建枚举器或调用 Reset 方法后， MoveNext 必须调用该方法，以便先将枚举器提升到集合的第一个元素，然后再读取属性的值 Current ;否则， Current 未定义并引发异常。

Current如果最后一次调用返回false，则还会引发异常，该调用MoveNext指示集合的末尾。

Current 不会移动枚举器的位置，并且连续调用以 Current 返回同一对象，直到 MoveNext 调用或 Reset 调用。

只要集合保持不变，枚举器就仍有效。 如果对集合进行了更改（如添加、修改或删除元素），则枚举器将失效并变为不可恢复;因此，下一次调用 MoveNext 或 Reset 引发一个 InvalidOperationException。 如果在调用和Current调用MoveNext之间修改集合，Current则返回它设置为的元素，即使枚举器已失效。