Current 属性

Gets the current Variable object from the collection.

命名空间:  Microsoft.SqlServer.Dts.Runtime
程序集:  Microsoft.SqlServer.ManagedDTS(在 Microsoft.SqlServer.ManagedDTS.dll 中)

语法

声明
Public ReadOnly Property Current As Variable
    Get
用法
Dim instance As VariableEnumerator
Dim value As Variable

value = instance.Current
public Variable Current { get; }
public:
property Variable^ Current {
    Variable^ get ();
}
member Current : Variable
function get Current () : Variable

属性值

类型:Microsoft.SqlServer.Dts.Runtime. . :: . .Variable
The current Variable object.

注释

After an enumerator is created, or after a call to the Reset method, the MoveNext method must be called to advance the enumerator to the first element of the collection before the enumerator can read the value of the Current property; otherwise, Current is undefined and an exception is thrown.

Current also throws an exception if the last call to MoveNext returned false, which indicates the end of the collection.

Current does not move the position of the enumerator, and consecutive calls to Current return the same object until either MoveNext or Reset is called.

An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is invalidated and becomes irrecoverable; thus, the next call to MoveNext or Reset throws an InvalidOperationException. However, if the collection is modified between calls to MoveNext and Current, Current returns the element that it is set to, even if the enumerator has been invalidated.

示例

The following code example adds a variable to the package. The code example uses various methods to locate the variable and print out the name, value, and namespace.

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SqlServer.Dts.Runtime;
namespace Adding_Variables
{
    class Program
    {
        static void Main(string[] args)
        {
            Application app = new Application();
            // Load a sample package that contains a variable that sets the File Name.
            Package pkg = app.LoadPackage(@"C:\Program Files\Microsoft SQL Server\100\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx", null);
            Variables pkgVars = pkg.Variables;
            Variable myVar = pkg.Variables.Add("myCustomVar", false, "User", "3");

            // See if the variable is in the collection now.
            Boolean hasMyVar = pkg.Variables.Contains("myCustomVar");
            Console.WriteLine("The variable was found? {0}", hasMyVar);

            // Loop over the collection using foreach keyword.
            foreach (Variable pkgVar in pkgVars)
            {
                // Only print variables from the User namespace.
                if (pkgVar.Namespace == "User")
                {
                Console.WriteLine("Variable: {0}, {1}", pkgVar.Name, pkgVar.Value.ToString());
                 }
            }
            Console.WriteLine("---------------------------");
            // Loop over the collection using the Enumerator. 
            VariableEnumerator myEnum = pkg.Variables.GetEnumerator();
            int i = 0;
            while ((myEnum.MoveNext()) && (myEnum.Current != null))
                // Again only show User namespace variables.
                if (myEnum.Current.Namespace == "User")
                {                
                    Console.WriteLine("[{0}] {1}, {2}", i++, myEnum.Current.Name, myEnum.Current.Namespace);
                }

            myEnum.Reset();
            Console.WriteLine("---------------------------");

            //Using the Item method syntax of [x], obtain the
            // first entry in the collection.
            myVar = pkgVars[0];
            Console.WriteLine("The name and namespace of the first variable is: {0}, {1}", myVar.Name, myVar.Namespace);
            String nameOfFirstItem = pkgVars[0].Name;
            Console.WriteLine("The name of the first variable is: {0}", nameOfFirstItem);
            //}
        }
    }
}
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SqlServer.Dts.Runtime

Namespace Adding_Variables
    Class Program
        Shared  Sub Main(ByVal args() As String)
            Dim app As Application =  New Application() 
            ' Load a sample package that contains a variable that sets the File Name.
            Dim pkg As Package =  app.LoadPackage("C:\Program Files\Microsoft SQL Server\100\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx",Nothing) 
            Dim pkgVars As Variables =  pkg.Variables 
            Dim myVar As Variable =  pkg.Variables.Add("myCustomVar",False,"User","3") 
 
            ' See if the variable is in the collection now.
            Dim hasMyVar As Boolean =  pkg.Variables.Contains("myCustomVar") 
            Console.WriteLine("The variable was found? {0}", hasMyVar)
 
            ' Loop over the collection using foreach keyword.
            Dim pkgVar As Variable
            For Each pkgVar In pkgVars
                ' Only print variables from the User namespace.
                If pkgVar.Namespace = "User" Then
                Console.WriteLine("Variable: {0}, {1}", pkgVar.Name, pkgVar.Value.ToString())
                End If
            Next
            Console.WriteLine("---------------------------")
            ' Loop over the collection using the Enumerator. 
            Dim myEnum As VariableEnumerator =  pkg.Variables.GetEnumerator() 
            Dim i As Integer =  0 
            While (myEnum.MoveNext()) &&(myEnum.Current <> Nothing)
                    Console.WriteLine("[{0}] {1}, {2}",i = Console.WriteLine("[{0}] {1}, {2}",i + 1
            End While
 
            myEnum.Reset()
            Console.WriteLine("---------------------------")
 
            'Using the Item method syntax of [x], obtain the
            ' first entry in the collection.
            myVar = pkgVars(0)
            Console.WriteLine("The name and namespace of the first variable is: {0}, {1}", myVar.Name, myVar.Namespace)
            Dim nameOfFirstItem As String =  pkgVars(0).Name 
            Console.WriteLine("The name of the first variable is: {0}", nameOfFirstItem)
            '}
        End Sub
    End Class
End Namespace

Sample Output:

The variable was found? True

Variable: myCustomVar, 3

---------------------------

[0] myCustomVar, User

---------------------------

The name and namespace of the first variable is: CancelEvent, System

The name of the first variable is: CancelEvent