Adding Data Flow Components Programmatically

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12/15/2008

更新： 2006 年 7 月 17 日

When you build a data flow, you start by adding components. Then you configure those components and connect them together to establish the flow of data at run time. This section describes adding a component to the data flow task, creating the design-time instance of the component, and then configuring the component. For information about how to connect components, see Connecting Data Flow Components Programmatically.

Adding a Component

Call the New method of the ComponentMetaDataCollection collection to create a new component and add it to the data flow task. This method returns the IDTSComponentMetaData90 interface of the component. However, at this point, the IDTSComponentMetaData90 does not contain information specific to any one component. Set the ComponentClassID property to identify the type of component. The data flow task uses the value of this property to create an instance of the component at run time.

The value specified in the ComponentClassID property can be the CLSID, PROGID, or CreationName property of the component. The CLSID is normally displayed in the Properties window as the value of the component's ComponentClassID property. For information about obtaining this property and other properties of available components, see Discovering Data Flow Components Programmatically.

Adding a Managed Component

You cannot use the CLSID or PROGID to add one the managed data flow components to the data flow, because these values point to a wrapper and not to the component itself. Instead you can use the CreationName property or the AssemblyQualifiedName property as shown in the following sample.

If you intend to use the AssemblyQualifiedName property, then you must add a reference in your Visual Studio project to the assembly that contains the managed component. These assemblies are not listed on the .NET tab of the Add Reference dialog box. Normally you must browse to locate the assembly in the C:\Program Files\Microsoft SQL Server\90\DTS\PipelineComponents folder.

The built-in managed data flow components include:

ADO.Net Source
XML Source
DataReader Destination
SQL Server 2005 Compact Edition Destination
Script Component

The following code sample shows both ways of adding a managed component to the data flow:

using System;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Pipeline;
using Microsoft.SqlServer.Dts.Pipeline.Wrapper;

namespace Microsoft.SqlServer.Dts.Samples
{
  class Program
  {
    static void Main(string[] args)
    {
      Microsoft.SqlServer.Dts.Runtime.Package package = new Microsoft.SqlServer.Dts.Runtime.Package();
      Executable e = package.Executables.Add("DTS.Pipeline.1");
      Microsoft.SqlServer.Dts.Runtime.TaskHost thMainPipe = (Microsoft.SqlServer.Dts.Runtime.TaskHost)e;
      MainPipe dataFlowTask = (MainPipe)thMainPipe.InnerObject;

      // The Application object will be used to obtain the CreationName
      //  of a PipelineComponentInfo from its PipelineComponentInfos collection.
      Application app = new Application();

      // Add a first ADO.Net source to the data flow.
      //  The CreationName property requires an Application instance.
      IDTSComponentMetaData90 component1 = dataFlowTask.ComponentMetaDataCollection.New();
      component1.Name = "DataReader Source";
      component1.ComponentClassID = app.PipelineComponentInfos["DataReader Source"].CreationName;

      // Add a second ADO.Net source to the data flow.
      //  The AssemblyQualifiedName property requires a reference to the assembly.
      IDTSComponentMetaData90 component2 = dataFlowTask.ComponentMetaDataCollection.New();
      component2.Name = "DataReader Source";
      component2.ComponentClassID = typeof(Microsoft.SqlServer.Dts.Pipeline.DataReaderSourceAdapter).AssemblyQualifiedName;
    }
  }
}

Imports Microsoft.SqlServer.Dts.Runtime
Imports Microsoft.SqlServer.Dts.Pipeline
Imports Microsoft.SqlServer.Dts.Pipeline.Wrapper

Module Module1

  Sub Main()

    Dim package As Microsoft.SqlServer.Dts.Runtime.Package = _
      New Microsoft.SqlServer.Dts.Runtime.Package()
    Dim e As Executable = package.Executables.Add("DTS.Pipeline.1")
    Dim thMainPipe As Microsoft.SqlServer.Dts.Runtime.TaskHost = _
      CType(e, Microsoft.SqlServer.Dts.Runtime.TaskHost)
    Dim dataFlowTask As MainPipe = CType(thMainPipe.InnerObject, MainPipe)

    ' The Application object will be used to obtain the CreationName
    '  of a PipelineComponentInfo from its PipelineComponentInfos collection.
    Dim app As New Application()

    ' Add a first ADO.Net source to the data flow.
    '  The CreationName property requires an Application instance.
    Dim component1 As IDTSComponentMetaData90 = _
      dataFlowTask.ComponentMetaDataCollection.New()
    component1.Name = "DataReader Source"
    component1.ComponentClassID = app.PipelineComponentInfos("DataReader Source").CreationName

    ' Add a second ADO.Net source to the data flow.
    '  The AssemblyQualifiedName property requires a reference to the assembly.
    Dim component2 As IDTSComponentMetaData90 = _
      dataFlowTask.ComponentMetaDataCollection.New()
    component2.Name = "DataReader Source"
    component2.ComponentClassID = _
      GetType(Microsoft.SqlServer.Dts.Pipeline.DataReaderSourceAdapter).AssemblyQualifiedName

  End Sub

End Module

Creating the Design-time Instance of the Component

Call the Instantiate method to create the design time instance of the component identified by the ComponentClassID property. This method returns the CManagedComponentWrapper object, which is the managed wrapper for the IDTSDesigntimeComponent90 interface.

Whenever possible, you should modify a component by using the methods of the design-time instance instead of by modifying the component metadata directly. Although there are items in the metadata that you must set directly, such as connections, generally it is inadvisable to modify the metadata directly because you bypass the ability of the component to monitor and validate changes.

Assigning Connections

Some components, such as the OLE DB Source component, require a connection to external data and use an existing ConnectionManager object in the package for this purpose. The Count property of the RuntimeConnectionCollection collection indicates the number of run-time ConnectionManager objects required by the component. If the count is greater than zero, the component requires a connection. Assign a connection manager from the package to the component by specifying the ConnectionManager and Name properties of the first connection in the RuntimeConnectionCollection. Note that the name of the connection manager in the run-time connection collection must match the name of the connection manager referenced from the package.

Setting the Values of Custom Properties

After creating the design-time instance of the component, call the ProvideComponentProperties method. This method is similar to a constructor because it initializes a newly created component by creating its custom properties and its input and output objects. Do not call ProvideComponentProperties more than one time on a component, because the component may reset itself and lose any modifications previously made to its metadata.

The CustomPropertyCollection of the component contains a collection of IDTSCustomProperty90 objects specific to the component. Unlike other programming models, where the properties of an object are always visible on the object, components only populate their custom property collections when you call the ProvideComponentProperties method. After you call method, use the SetComponentProperty method of the design-time instance of the component to assign values to its custom properties. This method accepts a name/value pair that identifies the custom property and provides its new value.

Initializing Output Columns

After you add a component to the task and configure it, initialize the collection of columns in the IDTSOutput90 of the object. This step is especially relevant for source components, but may not initialize the columns for transformation and destination components because they generally depend on the columns that they receive from upstream components.

Call the ReinitializeMetaData method to initialize the columns in the outputs of a source component. Because components do not automatically connect to external data sources, call the AcquireConnections method before calling ReinitializeMetaData to provide the component access to its external data source and the ability to populate its column metadata. Finally, call the ReleaseConnections method to release the connection.

Next Step

After adding and configuring the component, the next step is to create paths between components, which is discussed in the topic Connecting Data Flow Components Programmatically.

Sample

The following code sample adds the OLE DB Source component to a data flow task, creates a design-time instance of the component, and configures the component's properties. This example requires an additional reference to the assembly Microsoft.SqlServer.DTSRuntimeWrap.

using System;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Runtime.Wrapper;
using Microsoft.SqlServer.Dts.Pipeline;
using Microsoft.SqlServer.Dts.Pipeline.Wrapper;

namespace Microsoft.SqlServer.Dts.Samples
{
  class Program
  {
    static void Main(string[] args)
    {
      Runtime.Package package = new Runtime.Package();
      Executable e = package.Executables.Add("DTS.Pipeline.1");
      Runtime.TaskHost thMainPipe = e as Runtime.TaskHost;
      MainPipe dataFlowTask = thMainPipe.InnerObject as MainPipe;
      
      // Add an OLEDB connection manager to the package.
      ConnectionManager cm = package.Connections.Add("OLEDB");
      cm.Name = "OLEDB ConnectionManager";
      cm.ConnectionString = "Data Source=(local);" + 
        "Initial Catalog=AdventureWorks;Provider=SQLOLEDB.1;" + 
        "Integrated Security=SSPI;"
      
      // Add an OLE DB source to the data flow.
      IDTSComponentMetaData90 component = 
        dataFlowTask.ComponentMetaDataCollection.New();
      component.Name = "OLEDBSource";
      component.ComponentClassID = "DTSAdapter.OleDbSource.1";
      // You can also use the CLSID of the component instead of the PROGID.
      //component.ComponentClassID = "{2C0A8BE5-1EDC-4353-A0EF-B778599C65A0}";

      // Get the design time instance of the component.
      CManagedComponentWrapper instance = component.Instantiate();

      // Initialize the component
      instance.ProvideComponentProperties();

      // Specify the connection manager.
      if (component.RuntimeConnectionCollection.Count > 0)
      {
        component.RuntimeConnectionCollection[0].ConnectionManager = 
          DtsConvert.ToConnectionManager90(package.Connections[0]);
      }

      // Set the custom properties.
      instance.SetComponentProperty("AccessMode", 2);
      instance.SetComponentProperty("SqlCommand", 
        "Select * from Production.Product");

      // Reinitialize the metadata.
      instance.AcquireConnections(null);
      instance.ReinitializeMetaData();
      instance.ReleaseConnections();

      // Add other components to the data flow and connect them.
    }
  }
}

Imports Microsoft.SqlServer.Dts.Runtime
Imports Microsoft.SqlServer.Dts.Runtime.Wrapper
Imports Microsoft.SqlServer.Dts.Pipeline
Imports Microsoft.SqlServer.Dts.Pipeline.Wrapper

Module Module1

  Sub Main()

    Dim package As Microsoft.SqlServer.Dts.Runtime.Package = _
      New Microsoft.SqlServer.Dts.Runtime.Package()
    Dim e As Executable = package.Executables.Add("DTS.Pipeline.1")
    Dim thMainPipe As Microsoft.SqlServer.Dts.Runtime.TaskHost = _
      CType(e, Microsoft.SqlServer.Dts.Runtime.TaskHost)
    Dim dataFlowTask As MainPipe = CType(thMainPipe.InnerObject, MainPipe)

    ' Add an OLEDB connection manager to the package.
    Dim cm As ConnectionManager = package.Connections.Add("OLEDB")
    cm.Name = "OLEDB ConnectionManager"
    cm.ConnectionString = "Data Source=(local);" & _
      "Initial Catalog=AdventureWorks;Provider=SQLOLEDB.1;" & _
      "Integrated Security=SSPI;"

    ' Add an OLE DB source to the data flow.
    Dim component As IDTSComponentMetaData90 = _
      dataFlowTask.ComponentMetaDataCollection.New()
    component.Name = "OLEDBSource"
    component.ComponentClassID = "DTSAdapter.OleDbSource.1"
    ' You can also use the CLSID of the component instead of the PROGID.
    'component.ComponentClassID = "{2C0A8BE5-1EDC-4353-A0EF-B778599C65A0}";

    ' Get the design time instance of the component.
    Dim instance As CManagedComponentWrapper = component.Instantiate()

    ' Initialize the component.
    instance.ProvideComponentProperties()

    ' Specify the connection manager.
    If component.RuntimeConnectionCollection.Count > 0 Then
      component.RuntimeConnectionCollection(0).ConnectionManager = _
        DtsConvert.ToConnectionManager90(package.Connections(0))
    End If

    ' Set the custom properties.
    instance.SetComponentProperty("AccessMode", 2)
    instance.SetComponentProperty("SqlCommand", _
      "Select * from Production.Product")

    ' Reinitialize the metadata.
    instance.AcquireConnections(vbNull)
    instance.ReinitializeMetaData()
    instance.ReleaseConnections()

    ' Add other components to the data flow and connect them.

  End Sub

End Module

Change History

Release	History
2006 年 7 月 17 日	Changed content: Replaced code examples with longer samples. Added new section on managed components.

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