DtsEventHandler.PrecedenceConstraints Property

Article
12/03/2008

Returns a collection of precedence constraints, if any, found on the executables in this container. This property 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.

Remarks

A PrecedenceConstraints collection is a collection of PrecedenceConstraint objects.

Example

The following code example creates a DtsEventHandler for the OnError event in the package. This DtsEventHandler container contains two executables and establishes a precedence constraint between them. The code example displays the number of precedence constraints in the container.

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

namespace Microsoft.SqlServer.SSIS.Samples
{
    class Program
    {
        static void Main(string[] args)
        {
            Package pkg = new Package();
            // Set up a DtsEventHandler for the OnError event of the package.
            DtsEventHandler dtsEH = (DtsEventHandler)pkg.EventHandlers.Add("OnError");

            // Show the name and type of the properties in DtsEventHandler
            // using the Properties collection.
            DtsProperties props = dtsEH.Properties;
            String name;
            TypeCode propType;
            foreach (DtsProperty prop in props)
            {
                propType = prop.Type;
                name = prop.Name;
                Console.WriteLine("Name {0}, Type {1}", name, propType);
            }

            // When an OnError Event occurs, the Executables collection contains
            // the items to run. For this example, there will be a SendMailtTask
            // and a BulkInsertTask with a precedence constraint between them.
            Executable dtsEH1 = dtsEH.Executables.Add("STOCK:SendMailTask");
            TaskHost th = (TaskHost)dtsEH1;
            SendMailTask smTask = (SendMailTask)th.InnerObject;
            smTask.Subject = "Send Mail task";
            
            // Add a second executable to the DtsEventHandler.
            Executable dtsEH2 = dtsEH.Executables.Add("STOCK:BulkInsertTask");
            TaskHost th2 = (TaskHost)dtsEH2;

            // Add a precedence constraint between the two tasks.
            PrecedenceConstraint pc = dtsEH.PrecedenceConstraints.Add(dtsEH1, dtsEH2);
            pc.Value = DTSExecResult.Completion;

            // Review the number of constraints in the DtsEventHandler collection.
            PrecedenceConstraints pcDTSEH = dtsEH.PrecedenceConstraints;
            Console.WriteLine("Number of precedence constraints in DtsEventHandler: {0}", dtsEH.PrecedenceConstraints.Count);

            // Review the number of executables in the DtsEventHandler collection.
            Console.WriteLine("Number of executables in DtsEventHandler: {0}", dtsEH.Executables.Count);

            // Remove the first executable in the DtsEventHandler collection.
            dtsEH.Executables.Remove(0);
            Console.WriteLine("New number of exeutables in DtsEventHandler: {0}", dtsEH.Executables.Count);
        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports Microsoft.SqlServer.Dts.Runtime
Imports Microsoft.SqlServer.Dts.Tasks.SendMailTask
Imports Microsoft.SqlServer.Dts.Tasks.BulkInsertTask
 
Namespace Microsoft.SqlServer.SSIS.Samples
    Class Program
        Shared  Sub Main(ByVal args() As String)
            Dim pkg As Package =  New Package() 
            ' Set up a DtsEventHandler for the OnError event of the package.
            Dim dtsEH As DtsEventHandler = CType(pkg.EventHandlers.Add("OnError"), DtsEventHandler)
 
            ' Show the name and type of the properties in DtsEventHandler
            ' using the Properties collection.
            Dim props As DtsProperties =  dtsEH.Properties 
            Dim name As String
            Dim propType As TypeCode
            Dim prop As DtsProperty
            For Each prop In props
                propType = prop.Type
                name = prop.Name
                Console.WriteLine("Name {0}, Type {1}", name, propType)
            Next
 
            ' When an OnError Event occurs, the Executables collection contains
            ' the items to run. For this example, there will be a SendMailtTask
            ' and a BulkInsertTask with a precedence constraint between them.
            Dim dtsEH1 As Executable =  dtsEH.Executables.Add("STOCK:SendMailTask") 
            Dim th As TaskHost = CType(dtsEH1, TaskHost)
            Dim smTask As SendMailTask = CType(th.InnerObject, SendMailTask)
            smTask.Subject = "Send Mail task"
 
            ' Add a second executable to the DtsEventHandler.
            Dim dtsEH2 As Executable =  dtsEH.Executables.Add("STOCK:BulkInsertTask") 
            Dim th2 As TaskHost = CType(dtsEH2, TaskHost)
 
            ' Add a precedence constraint between the two tasks.
            Dim pc As PrecedenceConstraint =  dtsEH.PrecedenceConstraints.Add(dtsEH1,dtsEH2) 
            pc.Value = DTSExecResult.Completion
 
            ' Review the number of constraints in the DtsEventHandler collection.
            Dim pcDTSEH As PrecedenceConstraints =  dtsEH.PrecedenceConstraints 
            Console.WriteLine("Number of precedence constraints in DtsEventHandler: {0}", dtsEH.PrecedenceConstraints.Count)
 
            ' Review the number of executables in the DtsEventHandler collection.
            Console.WriteLine("Number of executables in DtsEventHandler: {0}", dtsEH.Executables.Count)
 
            ' Remove the first executable in the DtsEventHandler collection.
            dtsEH.Executables.Remove(0)
            Console.WriteLine("New number of exeutables in DtsEventHandler: {0}", dtsEH.Executables.Count)
        End Sub
    End Class
End Namespace

Sample Output:

Name CreationName, Type String

Name DelayValidation, Type Boolean

Name Description, Type String

Name Disable, Type Boolean

Name Executables, Type Object

Name ExecutionDuration, Type Int32

Name ExecutionResult, Type Object

Name ExecutionStatus, Type Object

Name Variables, Type Object

Number of precedence constraints in DtsEventHandler: 1

Number of executables in DtsEventHandler: 2

New number of exeutables in DtsEventHandler: 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