Package.PrecedenceConstraints 属性

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

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 PrecedenceConstraints As PrecedenceConstraints 
    Get
用法
Dim instance As Package 
Dim value As PrecedenceConstraints 

value = instance.PrecedenceConstraints

public PrecedenceConstraints PrecedenceConstraints { get; }

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

abstract PrecedenceConstraints : PrecedenceConstraints 
override PrecedenceConstraints : PrecedenceConstraints

final function get PrecedenceConstraints () : PrecedenceConstraints

属性值

类型：Microsoft.SqlServer.Dts.Runtime.PrecedenceConstraints
The collection of the PrecedenceConstraint objects.

实现

IDTSSequence.PrecedenceConstraints

注释

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 优先约束.

示例

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\100\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

请参阅

参考

Package 类

Microsoft.SqlServer.Dts.Runtime 命名空间