Sitecore Tip: Updating Datasources After Upgrading to Sitecore 7

UpdatingDatasources.cs

///
/// Updates the datasource for a rendering from an item path to using the
/// Sitecore ID for the item. The benefit is that this will allow datasources
/// to be able to be freely moved from one area of the content tree to another
/// while enabling the rendering to still function as expected.
///
///The Sitecore.Data.Items.Item to update the datasources for.
public void UpdateDataSourcePathToId(Sitecore.Data.Items.Item itemToProcess)
{
    if (null != itemToProcess)
    {
        // First we need to get the LayoutDefinition from the item using the predefined constant Sitecore.FieldIDs.LayoutField
        LayoutDefinition layout = LayoutDefinition.Parse(itemToProcess[Sitecore.FieldIDs.LayoutField]);

        if (layout != null)
        {
            // We want to go through all of the devices for the layout
            foreach (DeviceDefinition device in layout.Devices)
            {
                if (null != device.Renderings)
                {
                    foreach (RenderingDefinition definition in device.Renderings)
                    {
                        // Since we want to change paths to IDs, we make sure we have an existing
                        // datasource and that it is not already a Sitecore ID
                        if (!string.IsNullOrEmpty(definition.Datasource)
                        & amp; & !Sitecore.Data.ID.IsID(definition.Datasource))
{
                            // Check to see if we can get the item, we are assuming a path to an item and
                            // not a query
                            Item datasourceItem = Sitecore.Context.Database.Items.GetItem(definition.Datasource);

                            if (null != datasourceItem)
                            {
                                RenderingUtil.UpdateRenderingDatasource(layout, definition, itemToProcess, datasourceItem.ID.ToString());
                            }
                        }
                    }
                }
            }
        }
    }
}

UpdatingDatasources2.cs

/// 
/// Updates a datasource for a specific item in Sitecore.
/// 
///The Sitecore.Layouts.LayoutDefinition used by the item.
///The current Sitecore.Layouts.RenderingDefinition being processed for which the datasource will be updated.
///The Sitecore.Data.Items.Item to process.
///The new value to use for the datasource represented as a string.
public static void UpdateRenderingDatasource(Sitecore.Layouts.LayoutDefinition layout, Sitecore.Layouts.RenderingDefinition rendering, Sitecore.Data.Items.Item itemToUpdate, string newDatasourceValue)
{
    if (null != rendering & amp; & null != itemToUpdate
          & amp; & !string.IsNullOrEmpty(newDatasourceValue))
            {
        // We store this to use in logging
        string originalDatasourceValue = rendering.Datasource;

        // We only want to update values that have actually changed
        if (!originalDatasourceValue.Equals(newDatasourceValue, StringComparison.OrdinalIgnoreCase))
        {
            // We need to change the datasource and get the full XML for the layout in order to perform the update
            rendering.Datasource = newDatasourceValue;
            string updatedLayoutInformation = layout.ToXml();

            using (new Sitecore.SecurityModel.SecurityDisabler())
            {
                // We need to disable security since it may be run outside of admin context and begin editing the item  
                itemToUpdate.Editing.BeginEdit();

                try
                {
                    itemToUpdate.Fields[Sitecore.FieldIDs.LayoutField].Value = updatedLayoutInformation;
                    itemToUpdate.Editing.EndEdit();
                    Sitecore.Diagnostics.Log.Info(string.Format("UpdateRenderingDatasource: Datasource updated on item: {0} from {1} to {2}", itemToUpdate.Paths.FullPath, originalDatasourceValue, newDatasourceValue), typeof(RenderingUtil));
                }
                catch (Exception xcp)
                {
                    itemToUpdate.Editing.CancelEdit();
                    Sitecore.Diagnostics.Log.Error("UpdateRenderingDatasource: Failed to update datasource.", xcp, typeof(RenderingUtil));
                }
            }
        }
        else
        {
            Sitecore.Diagnostics.Log.Warn("UpdateRenderingDatasource: Datasource value is unchanged.", typeof(RenderingUtil));
        }
    }
            else
            {
        Sitecore.Diagnostics.Log.Warn("UpdateRenderingDatasource: Unable to process datasource change.  The item to update or rendering is null or a new datasource value has not been specified.", typeof(RenderingUtil));
    }
}