PrecedenceConstraints.Item[Object] Propriété

public:
 property Microsoft::SqlServer::Dts::Runtime::PrecedenceConstraint ^ default[System::Object ^] { Microsoft::SqlServer::Dts::Runtime::PrecedenceConstraint ^ get(System::Object ^ index); };

public Microsoft.SqlServer.Dts.Runtime.PrecedenceConstraint this[object index] { get; }

member this.Item(obj) : Microsoft.SqlServer.Dts.Runtime.PrecedenceConstraint

Default Public ReadOnly Property Item(index As Object) As PrecedenceConstraint

Paramètres

Valeur de propriété

PrecedenceConstraint

Objet PrecedenceConstraint de la collection.

Exemples

L’exemple de code suivant crée deux contraintes de priorité. Il utilise Contains ensuite pour vérifier l’existence d’une contrainte spécifique, compte le nombre de contraintes avant et après l’utilisation de la Remove méthode, et montre comment utiliser l’itération GetEnumerator sur la collection, à l’aide de la Item[] syntaxe de pConsts[i].ID retour ID de la contrainte.

using System;  
using System.Collections.Generic;  
using System.Text;  
using Microsoft.SqlServer.Dts.Runtime;  
using Microsoft.SqlServer.Dts.Tasks.FileSystemTask;  
using Microsoft.SqlServer.Dts.Tasks.BulkInsertTask;  

namespace PrecedenceConst  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            Package pkg = new Package();  
            // Add a File System task.  
            Executable eFileTask1 = pkg.Executables.Add("STOCK:FileSystemTask");  
            TaskHost thFileTask1 = eFileTask1 as TaskHost;  

            // Add a second File System task.  
            Executable eFileTask2 = pkg.Executables.Add("STOCK:FileSystemTask");  
            TaskHost thFileTask2 = eFileTask2 as TaskHost;  

            // Add a Bulk Insert task.  
            Executable eBulkInsert = pkg.Executables.Add("STOCK:BulkInsertTask");  
            TaskHost thBulkInsert = eBulkInsert as TaskHost;  

            // Add a precedence constraint between eFileTask1 and eFileTask2.  
            // Set the constraint to be that eFileTask2 cannot run   
            // until eFileTask1 completes.  
            PrecedenceConstraint pcFileTasks = pkg.PrecedenceConstraints.Add(eFileTask1, eFileTask2);  
            pcFileTasks.Name = "constraint between File System Tasks";  

            // Add another precedence constraint. Add it between eFileTask2 and BulkInsert.  
            // Again, set the constraint to be that BulkInsert cannot run   
            // until eFileTask2 completes.  
            PrecedenceConstraint pcFiletoBulk = pkg.PrecedenceConstraints.Add(eFileTask2, eBulkInsert);  
            pcFileTasks.Name = "constraint between File System and Bulk Insert Tasks";  

            // Obtain the precedence constraint collection.  
            PrecedenceConstraints pConsts = pkg.PrecedenceConstraints;  
            Boolean containsConstraint = pkg.PrecedenceConstraints.Contains("constraint between File System and Bulk Insert Tasks");  
            Console.WriteLine("Contains the constraint between File System and Bulk Insert Tasks? {0}", containsConstraint);  

            // Create the enumerator.  
            PrecedenceConstraintEnumerator myEnumerator = pConsts.GetEnumerator();  
            // Iterate over the collection, and remove the Bulk Insert task.  
            int i = 0;  
            while ((myEnumerator.MoveNext()) && (myEnumerator.Current != null))  
            {  
                Console.WriteLine("ID {0}", pConsts[i].ID);  
            }  

            Console.WriteLine("Number of constraints {0}", pConsts.Count);  
            // Remove the second contstraint.  
            pConsts.Remove(1);  
            // Verify that one has been removed.  
            Console.WriteLine("Number of constraints {0}", pConsts.Count);  

            Console.WriteLine();  
        }  
    }  
}  

Imports System  
Imports System.Collections.Generic  
Imports System.Text  
Imports Microsoft.SqlServer.Dts.Runtime  
Imports Microsoft.SqlServer.Dts.Tasks.FileSystemTask  
Imports Microsoft.SqlServer.Dts.Tasks.BulkInsertTask  

Namespace PrecedenceConst  
    Class Program  
        Shared  Sub Main(ByVal args() As String)  
            Dim pkg As Package =  New Package()   
            ' Add a File System task.  
            Dim eFileTask1 As Executable =  pkg.Executables.Add("STOCK:FileSystemTask")   
            Dim thFileTask1 As TaskHost =  eFileTask1 as TaskHost   

            ' Add a second File System task.  
            Dim eFileTask2 As Executable =  pkg.Executables.Add("STOCK:FileSystemTask")   
            Dim thFileTask2 As TaskHost =  eFileTask2 as TaskHost   

            ' Add a Bulk Insert task.  
            Dim eBulkInsert As Executable =  pkg.Executables.Add("STOCK:BulkInsertTask")   
            Dim thBulkInsert As TaskHost =  eBulkInsert as TaskHost   

            ' Add a precedence constraint between eFileTask1 and eFileTask2.  
            ' Set the constraint to be that eFileTask2 cannot run   
            ' until eFileTask1 completes.  
            Dim pcFileTasks As PrecedenceConstraint =  pkg.PrecedenceConstraints.Add(eFileTask1,eFileTask2)   
            pcFileTasks.Name = "constraint between File System Tasks"  

            ' Add another precedence constraint. Add it between eFileTask2 and BulkInsert.  
            ' Again, set the constraint to be that BulkInsert cannot run   
            ' until eFileTask2 completes.  
            Dim pcFiletoBulk As PrecedenceConstraint =  pkg.PrecedenceConstraints.Add(eFileTask2,eBulkInsert)   
            pcFileTasks.Name = "constraint between File System and Bulk Insert Tasks"  

            ' Obtain the precedence constraint collection.  
            Dim pConsts As PrecedenceConstraints =  pkg.PrecedenceConstraints   
            Dim containsConstraint As Boolean =  pkg.PrecedenceConstraints.Contains("constraint between File System and Bulk Insert Tasks")   
            Console.WriteLine("Contains the constraint between File System and Bulk Insert Tasks? {0}", containsConstraint)  

            ' Create the enumerator.  
            Dim myEnumerator As PrecedenceConstraintEnumerator =  pConsts.GetEnumerator()   
            ' Iterate over the collection, and remove the Bulk Insert task.  
            Dim i As Integer =  0   
            While (myEnumerator.MoveNext()) &&(myEnumerator.Current <> Nothing)  
                Console.WriteLine("ID {0}", pConsts(i).ID)  
            End While  

            Console.WriteLine("Number of constraints {0}", pConsts.Count)  
            ' Remove the second contstraint.  
            pConsts.Remove(1)  
            ' Verify that one has been removed.  
            Console.WriteLine("Number of constraints {0}", pConsts.Count)  

            Console.WriteLine()  
        End Sub  
    End Class  
End Namespace  

Exemple de sortie :

Contient la contrainte entre le système de fichiers et les tâches d’insertion en bloc ? True

ID {BA42AF32-3AC1-4CB6-85A2-289760ADBFA4}

ID {BA42AF32-3AC1-4CB6-85A2-289760ADBFA4}

Nombre de contraintes 2

Nombre de contraintes 1

Remarques

Si l’appel à la Contains méthode retourne true, vous pouvez accéder à l’élément spécifié dans la collection à l’aide de la syntaxe PrecedenceConstraints[index]. Toutefois, si la Contains méthode retourne false, cette propriété lève une exception. En C#, cette propriété est l'indexeur correspondant à la classe PrecedenceConstraints.

S’applique à