gistfile1.cs

private void SoftDelete(DbEntityEntry entry)
{
	Type entryEntityType = entry.Entity.GetType();

	string tableName = GetTableName(entryEntityType);
	string primaryKeyName = GetPrimaryKeyName(entryEntityType);

	string sql =
		string.Format(
			"UPDATE {0} SET IsDeleted = 1 WHERE {1} = @id",
				tableName, primaryKeyName);

	Database.ExecuteSqlCommand(
		sql,
		new SqlParameter("@id", entry.OriginalValues[primaryKeyName]));

	// prevent hard delete            
	entry.State = EntityState.Detached;
}