“Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created. You have either made changes to a table that can’t be re-created or enabled the option Prevent saving changes that require the table to be re-created.”

To avoid this warning message, go to the “tools” menu, then click “Options”

Click on the “Designer” node

Then  uncheck the “Prevent saving changes that require table re-creation” checkbox

And you are done, the message box will not appears anymore

my extension method

public static SPFolder GetParentFolder(this SPListItem spListItem)

{

if (spListItem == null)

return null;

SPFile spFile = spListItem.Web.GetFile(spListItem.Url);

if (spFile == null)

return null;

return spFile.ParentFolder;

}

Use

SPFolder parentFolder = sPListItem.GetParentFolder();

if (parentFolder != null)

{

// do some stuffs..

}