IChangeDataRetriever.LoadChangeData Method

When overridden in a derived class, this method retrieves item data for a change.

Namespace: Microsoft.Synchronization
Assembly: Microsoft.Synchronization (in microsoft.synchronization.dll)

Syntax

'Declaration
Function LoadChangeData ( _
    loadChangeContext As LoadChangeContext _
) As Object
'Usage
Dim instance As IChangeDataRetriever
Dim loadChangeContext As LoadChangeContext
Dim returnValue As Object

returnValue = instance.LoadChangeData(loadChangeContext)

Object LoadChangeData (
    LoadChangeContext loadChangeContext
)

Object^ LoadChangeData (
    LoadChangeContext^ loadChangeContext
)

Object LoadChangeData (
    LoadChangeContext loadChangeContext
)

function LoadChangeData (
    loadChangeContext : LoadChangeContext
) : Object

Parameters

• loadChangeContext
  Metadata that describes the change for which data should be retrieved.

Return Value

The item data for the change.

Remarks

The source provider determines the type of object that is returned by this method. The object can be as simple as a boxed value type or as complex as a class that contains methods for advanced data retrieval.

Example

The following example shows how to implement the LoadChangeData method to retrieve the data for a specified set of change units. This example returns the data as a sparsely-populated array of strings.

Public Function LoadChangeData(ByVal loadChangeContext As LoadChangeContext) As Object Implements IChangeDataRetriever.LoadChangeData
    ' Sanity check to ensure the data array is not overrun.
    If Contact.ChangeUnitFieldCount < loadChangeContext.ItemChange.ChangeUnitChanges.Count Then
        Throw New ArgumentOutOfRangeException("LoadChangeData received too many change unit changes.")
    End If

    ' Get the ID of the item to return.
    Dim itemId As SyncId = loadChangeContext.ItemChange.ItemId

    ' Create a string array to hold the data for each change unit. Some of the elements of this array
    ' may be empty.
    Dim contactData As String() = New String(Contact.ChangeUnitFieldCount - 1) {}

    ' Enumerate the change units to retrieve.
    For iChange As Integer = 0 To loadChangeContext.ItemChange.ChangeUnitChanges.Count - 1
        ' Retrieve data for the specified change unit and put the data into the appropriate
        ' place in the string array.
        Dim icu As Integer = loadChangeContext.ItemChange.ChangeUnitChanges(iChange).ChangeUnitId.GetByteId()
        contactData(icu) = _ContactStore.GetContactData(itemId, loadChangeContext.ItemChange.ChangeUnitChanges(iChange).ChangeUnitId)
    Next
    Return contactData
End Function

public object LoadChangeData(LoadChangeContext loadChangeContext)
{
    // Sanity check to ensure the data array is not overrun.
    if (Contact.ChangeUnitFieldCount < loadChangeContext.ItemChange.ChangeUnitChanges.Count)
    {
        throw new ArgumentOutOfRangeException("LoadChangeData received too many change unit changes.");
    }

    // Get the ID of the item to return.
    SyncId itemId = loadChangeContext.ItemChange.ItemId;

    // Create a string array to hold the data for each change unit. Some of the elements of this array
    // may be empty.
    string[] contactData = new string[Contact.ChangeUnitFieldCount];

    // Enumerate the change units to retrieve.
    for (int iChange = 0; iChange < loadChangeContext.ItemChange.ChangeUnitChanges.Count; iChange++)
    {
        // Retrieve data for the specified change unit and put the data into the appropriate
        // place in the string array.
        int icu = loadChangeContext.ItemChange.ChangeUnitChanges[iChange].ChangeUnitId.GetByteId();
        contactData[icu] = _ContactStore.GetContactData(itemId,
            loadChangeContext.ItemChange.ChangeUnitChanges[iChange].ChangeUnitId);
    }
    return contactData;
}

See Also

Reference

IChangeDataRetriever Interface
IChangeDataRetriever Members
Microsoft.Synchronization Namespace