Delete all entities in Entity Framework

This will perform much, much better than anything involving deleting individual entity objects, assuming the underlying database is MSSQL.

foreach (var tableName in listOfTableNames)
{
    context.ExecuteStoreCommand("TRUNCATE TABLE [" + tableName + "]");
}

Of course, if your tables have foreign-key relationships, you’ll need to set up your list of table names in the proper order so that you clear foreign-key tables before you clear any primary-key tables that they might depend upon.