IDTSVirtualInput90 Interface

Článek
12/03/2008

Represents the columns available to a component from the upstream component.

Namespace: Microsoft.SqlServer.Dts.Pipeline.Wrapper
Assembly: Microsoft.SqlServer.DTSPipelineWrap (in microsoft.sqlserver.dtspipelinewrap.dll)

Syntax

'Declaration
<GuidAttribute("B9A5E5EB-4BFC-48AF-95E9-6344C6794340")> _
<TypeLibTypeAttribute(4160)> _
Public Interface IDTSVirtualInput90
    Inherits IDTSObject90

[GuidAttribute("B9A5E5EB-4BFC-48AF-95E9-6344C6794340")] 
[TypeLibTypeAttribute(4160)] 
public interface IDTSVirtualInput90 : IDTSObject90

[GuidAttribute(L"B9A5E5EB-4BFC-48AF-95E9-6344C6794340")] 
[TypeLibTypeAttribute(4160)] 
public interface class IDTSVirtualInput90 : IDTSObject90

/** @attribute GuidAttribute("B9A5E5EB-4BFC-48AF-95E9-6344C6794340") */ 
/** @attribute TypeLibTypeAttribute(4160) */ 
public interface IDTSVirtualInput90 extends IDTSObject90

GuidAttribute("B9A5E5EB-4BFC-48AF-95E9-6344C6794340") 
TypeLibTypeAttribute(4160) 
public interface IDTSVirtualInput90 extends IDTSObject90

Remarks

The IDTSVirtualInput90 is retrieved by calling the GetVirtualInput method of an IDTSInput90 object. The VirtualInputColumnCollection property contains the columns that are available from the upstream components in the graph.

When programmatically building a data flow task, the virtual columns are selected for a component by calling the SetUsageType method of the CManagedComponentWrapperClass.

Developers writing custom data flow components use the virtual input to discover the available upstream columns, and, depending on the component, to add columns to the input based on the columns in the virtual collection.

Because the virtual input is a reflection of upstream columns, modifications to the virtual input or the columns in the virtual input collection do not have any impact on the IDTSOutput90 itself.

Example

The following code example shows how to use the virtual input to select the columns used by a component when programmatically building the data flow task.

public void SelectColumns(IDTSComponentMetaData90 md)
{
    // Create the design time instance of the component.
    CManagedComponentWrapper wrp = md.Instantiate();

    // Walk the input collection.
    foreach (IDTSInput90 input in md.InputCollection)
    {
        // Get the virtual input columns.
        IDTSVirtualInput90 vInput = input.GetVirtualInput();

        // For each virtual column, set its usagetype to READONLY.
        foreach (IDTSVirtualInputColumn90 vCol in vInput.VirtualInputColumnCollection)
            wrp.SetUsageType(input.ID, vInput, vCol.LineageID, DTSUsageType.UT_READONLY);
    }
}

Public Sub SelectColumns(ByVal md As IDTSComponentMetaData90) 
 Dim wrp As CManagedComponentWrapper = md.Instantiate 
 For Each input As IDTSInput90 In md.InputCollection 
   Dim vInput As IDTSVirtualInput90 = input.GetVirtualInput 
   For Each vCol As IDTSVirtualInputColumn90 In vInput.VirtualInputColumnCollection 
     wrp.SetUsageType(input.ID, vInput, vCol.LineageID, DTSUsageType.UT_READONLY) 
   Next 
 Next 
End Sub

The following code example shows a custom data flow component that selects all of the DT_STR columns from the virtual input when the input is connected to a path.

public override void OnInputPathAttached(int inputID)
{
    IDTSInput90 input = ComponentMetaData.InputCollection.GetObjectByID(inputID);
    IDTSVirtualInput90 vInput = input.GetVirtualInput();

    foreach (IDTSVirtualInputColumn90 vCol in vInput.VirtualInputColumnCollection)
    {
        if (vCol.DataType == DataType.DT_STR)
        {
            this.SetUsageType(inputID, vInput, vCol.LineageID, DTSUsageType.UT_READONLY);
        }
    }
}

Public Overrides Sub OnInputPathAttached(ByVal inputID As Integer) 
 Dim input As IDTSInput90 = ComponentMetaData.InputCollection.GetObjectByID(inputID) 
 Dim vInput As IDTSVirtualInput90 = input.GetVirtualInput 
 For Each vCol As IDTSVirtualInputColumn90 In vInput.VirtualInputColumnCollection 
   If vCol.DataType = DataType.DT_STR Then 
     Me.SetUsageType(inputID, vInput, vCol.LineageID, DTSUsageType.UT_READONLY) 
   End If 
 Next 
End Sub

Platforms

Development Platforms

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

Target Platforms

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

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