Flutter – Unable to get correct correct Provider from BlocProvider

I have a page which contains a button. When the user presses the button, a dialog box shows up which contains a bunch of textfields, etc. There is a toggle in that dialog box which changes the GridView based on what the user toggles.

The set up is:
In my main class, I have:

void main() {
  Bloc.observer = const GlobalApplicationObserver();
  ExpenditureRepository expenditureRepository = ExpenditureRepository();
  //runApp(MyApp());
  runApp(MaterialApp(
      home: MultiBlocProvider(
    providers: [
      // BlocProvider<OnboardingBloc>(
      //     create: (BuildContext context) => OnboardingBloc()),
      BlocProvider<FinanceBloc>(
          create: (BuildContext context) => FinanceBloc(expenditureRepository)),
    ],
    child: OnboardingPageWidget(),
  )));
}

In my OnboardingPageWidget (a stateful widget, I have, I have a button):

Center(
child: IconButton(
style: TextButton.styleFrom(
backgroundColor: Colors.black,
foregroundColor: Colors.white),
onPressed: () => showDialog<String>(
context: context,
builder: (BuildContext _) => expenditureForm
.showAddExpenditureDialogBox(context, true),
),
tooltip: 'Click to add an expense!',
icon: const Icon(Icons.add),
))

And in my showAddExpenditureDialogBox method, it consists of:

class ExpenditureForm {
  AlertDialog showAddExpenditureDialogBox(
      BuildContext context, isFixedExpenditure) {
    final amountTextEditingController = TextEditingController();
    final IncomeOrExpenseToggle incomeExpense = IncomeOrExpenseToggle(context);
    final List<String> list = <String>['Travel', 'Food', 'Bill'];
    final nameOfExpenditureTextEditingController = TextEditingController();
    String categoryOfExpenditure = "Travel";

    return AlertDialog(
      title: const Text('Expenditure'),
      content: const Text('Input details about it!'),
      actions: <Widget>[
        Column(
          children: [
            Container(child: Center(child: incomeExpense)),

            Row(
              children: [
                Expanded(
                  flex: 3,
                  child: Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: TextField(
                      controller: nameOfExpenditureTextEditingController,
                      decoration: InputDecoration(hintText: 'Name of expense'),
                    ),
                  ),
                ),
                Expanded(
                  flex: 1,
                  child: Container(
                    width: MediaQuery.of(context).size.width * 0.3,
                    child: TextField(
                      controller: amountTextEditingController,
                      decoration: InputDecoration(hintText: 'Amount - £'),
                    ),
                  ),
                ),
              ],
            ),

            //This is practising drop down menus
            DropdownMenu<String>(
              initialSelection: list.first,
              onSelected: (value) => {categoryOfExpenditure = value!},
              dropdownMenuEntries:
                  list.map<DropdownMenuEntry<String>>((String value) {
                return DropdownMenuEntry<String>(value: value, label: value);
              }).toList(),
            ),
            // SizedBox(
            //   child: BlocBuilder<FinanceBloc, FinanceState>(
            //       buildWhen: (previous, current) => current is TypeToggledState,
            //       builder: (context, state) {
            //         if (state is TypeToggledState) {
            //           if (state.income) {
            //             return SizedBox(
            //               width: MediaQuery.of(context).size.width * 1,
            //               height: MediaQuery.of(context).size.height * 0.5,
            //               child: GridView.count(
            //                 crossAxisCount: 2,
            //                 children: List.generate(100, (index) {
            //                   return Center(
            //                     child: Text(
            //                       'Item $index',
            //                       style:
            //                           Theme.of(context).textTheme.headlineSmall,
            //                     ),
            //                   );
            //                 }),
            //               ),
            //             );
            //           } else {
            //             return SizedBox(
            //               width: MediaQuery.of(context).size.width * 1,
            //               height: MediaQuery.of(context).size.height * 0.5,
            //               child: GridView.count(
            //                 crossAxisCount: 2,
            //                 children: List.generate(23, (index) {
            //                   return Center(
            //                     child: Text(
            //                       'Item $index',
            //                       style:
            //                           Theme.of(context).textTheme.headlineSmall,
            //                     ),
            //                   );
            //                 }),
            //               ),
            //             );
            //           }
            //         }
            //         return SizedBox(
            //           width: MediaQuery.of(context).size.width * 1,
            //           height: MediaQuery.of(context).size.height * 0.5,
            //           child: GridView.count(
            //             crossAxisCount: 2,
            //             children: List.generate(100, (index) {
            //               return Center(
            //                 child: Text(
            //                   'Item $index',
            //                   style: Theme.of(context).textTheme.headlineSmall,
            //                 ),
            //               );
            //             }),
            //           ),
            //         );
            //       }),
            // ),

            TextButton(
              onPressed: () => Navigator.of(context, rootNavigator: true).pop(),
              child: const Text('Cancel'),
            ),

            TextButton(
              onPressed: () => saveExpenditure(
                  context,
                  amountTextEditingController.text,
                  categoryOfExpenditure,
                  nameOfExpenditureTextEditingController.text,
                  incomeExpense.getToogle(),
                  isFixedExpenditure),
              child: const Text('Save'),
            )
          ],
        )
      ],
    );
  }

  void saveExpenditure(
      BuildContext context,
      String amountOfExpenditure,
      String categoryOfExpenditure,
      String nameOfExpenditure,
      bool isIncome,
      bool isFixed) {
    Expenditure expenditure = Expenditure(
        nameOfExpenditure: nameOfExpenditure,
        amountOfExpenditure: amountOfExpenditure,
        categoryOfExpenditure: categoryOfExpenditure,
        typeOfExpenditure: isIncome == true ? "Income" : "Expense",
        isFixedExpenditure: isFixed);

    context.read<FinanceBloc>().add(SaveFinanceEvent(expenditure));

    //Closing the popup
    Navigator.of(context, rootNavigator: true).pop();
  }
}

Now when I uncomment out the bloc of code in the showAddExpenditureDialogBox method, I get the following:

Error: Could not find the correct Provider<FinanceBloc> above this BlocBuilder<FinanceBloc,
FinanceState> Widget

This happens because you used a `BuildContext` that does not include the provider
of your choice. There are a few common scenarios:

- You added a new provider in your `main.dart` and performed a hot-reload.
  To fix, perform a hot-restart.

- The provider you are trying to read is in a different route.

  Providers are "scoped". So if you insert of provider inside a route, then
  other routes will not be able to access that provider.

- You used a `BuildContext` that is an ancestor of the provider you are trying to read.

  Make sure that BlocBuilder<FinanceBloc, FinanceState> is under your
MultiProvider/Provider<FinanceBloc>.

I don’t see how or why the error is occurring. From what I see, the bloc provider is being created at the entry point of the app, being passed into OnboardingPageWidget, and then being passed into the ExpenditureForm class via constructor. So surely I should be able to use the context form the constructor to use BlocBuilder? I think it might be stemming from the fact that there is not overrided build method in my ExpenditureForm class? The reason why I created an explicit class and not extending a stateful/stateless widget is because this alert dialog box is being used in another place in my app.