VariableEnumerator.Current Property

Article
12/15/2008

Gets the current Variable object from the collection.

Espace de noms: Microsoft.SqlServer.Dts.Runtime
Assembly: Microsoft.SqlServer.ManagedDTS (in microsoft.sqlserver.manageddts.dll)

Syntaxe

'Déclaration
Public ReadOnly Property Current As Variable

public Variable Current { get; }

public:
property Variable^ Current {
    Variable^ get ();
}

/** @property */
public Variable get_Current ()

public function get Current () : Variable

Valeur de propriété

The current Variable object.

Notes

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.

Exemple

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\90\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\90\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

Sécurité des threads

Any public static (Shared in Microsoft Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Plateformes

Plateformes de développement

Pour obtenir la liste des plateformes prises en charge, consultez Configuration matérielle et logicielle requise pour l'installation de SQL Server 2005.

Plateformes cibles