Package.PrecedenceConstraints Property

Artikkeli
12/03/2008

Returns the collection of PrecedenceConstraint objects. This field is read-only.

Namespace: Microsoft.SqlServer.Dts.Runtime
Assembly: Microsoft.SqlServer.ManagedDTS (in microsoft.sqlserver.manageddts.dll)

Syntax

'Declaration
Public ReadOnly Property PrecedenceConstraints As PrecedenceConstraints

public PrecedenceConstraints PrecedenceConstraints { get; }

public:
virtual property PrecedenceConstraints^ PrecedenceConstraints {
    PrecedenceConstraints^ get () sealed;
}

/** @property */
public final PrecedenceConstraints get_PrecedenceConstraints ()

public final function get PrecedenceConstraints () : PrecedenceConstraints

Property Value

A PrecedenceConstraints collection that contains PrecedenceConstraint objects.

Remarks

Returns the collection of PrecedenceConstraint objects that contain information about conditions that must occur before a step can be released for execution. For more information about precedence constraints, see Precedence Constraints.

Example

The following code example adds two tasks to the package, and places a precedence constraing between them. It then counts the number of constraints in the package collection.

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

namespace DataFlow_Conceptual
{
    class Program
    {
        static void Main(string[] args)
        {
            Package p = new Package();
            // Add a File System task.
            Executable eFileTask1 = p.Executables.Add("STOCK:FileSystemTask");
            TaskHost thFileHost1 = eFileTask1 as TaskHost;

            // Add a second File System task.
            Executable eFileTask2 = p.Executables.Add("STOCK:FileSystemTask");
            TaskHost thFileHost2 = eFileTask2 as TaskHost;

            // Put a precedence constraint between the tasks.
            // Set the constraint to be that thFileTask2 cannot run
            // unless thFileTask1 completes.
            PrecedenceConstraint pcFileTasks = p.PrecedenceConstraints.Add((Executable)thFileHost1, (Executable) thFileHost2);
            pcFileTasks.Value = DTSExecResult.Completion;

            // Return and show the count of precedence constraints in the package.
            PrecedenceConstraints pCons = p.PrecedenceConstraints;
            Console.WriteLine("Precedence constraints in package = {0}",  pCons.Count);

        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SqlServer.Dts.Runtime
 
Namespace Package_API
    Class Program
        Shared  Sub Main(ByVal args() As String)
            Dim app As Application =  New Application() 
            Dim pkg As Package =  New Package() 
            pkg = app.LoadPackage("C:\Program Files\Microsoft SQL Server\90\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx", Nothing)
 
            ' Show the package type
            Console.WriteLine("The package type is {0}", pkg.PackageType)
        End Sub
    End Class
End Namespace

Sample Output:

Precedence constraints in package = 1

Thread Safety

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.

Platforms

Development Platforms

For a list of the supported platforms, see Hardware and Software Requirements for Installing SQL Server 2005.

Target Platforms