How do I access the variable of one method from another method within the same class C#?

Question

I'm working on Asp.net project. I created a Form, which asks for connectionId and holderFirstName as Input. The name of asp-action is SendProofNameRequest.

In Controller, I wrote a Method SendProofNameRequest which take connectionId and holderFirstName as Parameters. But the problem is, the purpose I'm taking holderFirstName as Input is to use this in another Method (VerifyFirstName).

So, my question is how to take holderFirstName as input from user and use this in another method / VerifyFirstName (not SendProofNameRequest).

Details.cshtml

    <form class="input-group mb-3" asp-controller="Proof" asp-action="SendProofNameRequest">
        <input type="hidden" name="connectionId" value="@Model.Connection.Id" />
        <input type="text" name="holderFirstName" autocomplete="off" class="form-control" placeholder="Enter First Name" aria-label="First Name" aria-describedby="basic-addon2">
        <div class="input-group-append">
            <button class="btn btn-outline-info" type="submit">Request a Proof of First Name</button>
        </div>
    </form> 

ProofController.cs

    [HttpPost]
    public async Task<IActionResult> SendProofNameRequest(string connectionId, out string holderFirstName)
    {
        var agentContext = await _agentProvider.GetContextAsync();
        var connectionRecord = await _walletRecordService.GetAsync<ConnectionRecord>(agentContext.Wallet, connectionId);
        var proofNameRequest = await CreateProofNameMessage(connectionRecord);
        await _messageService.SendAsync(agentContext.Wallet, proofNameRequest, connectionRecord);

        return RedirectToAction("Index");
    }

VerifyFirstName Method

I want to replace firstname (static value) with holderFirstName (dynamic value / user entered in form)

    public bool VerifyFirstName(PartialProof proof)
    {
        var firstName = "Fyodor";
        var name = proof.RequestedProof.RevealedAttributes.First();
        if (name.Value.Raw.Equals(firstName))
        { 
            return true; 
        }

        return false;
    }

UPDATE

As u said to add models, I did that... add the models in ViewModel page and call the @model in View page..

Now, to call the stored values in model in Verify methods controller.

VerifyProof(string proofRecordId) methods calls for another method VerifyFirstName(proof) which does the actual verification.

Kindly have a look at code and can u point out where to add model.HolderFirstName and SendNameRequestViewModel model in which method e.g. VerifyProof(string proofRecordId), VerifyFirstName(proof).. I was getting an errors..

    [HttpGet]
    public async Task<IActionResult> VerifyProof(string proofRecordId, SendNameRequestViewModel model)
    {
        var agentContext = await _agentProvider.GetContextAsync();
        var proofRecord = await _proofService.GetAsync(agentContext, proofRecordId);
        var request = JsonConvert.DeserializeObject<ProofRequest>(proofRecord.RequestJson);
        var proof = JsonConvert.DeserializeObject<PartialProof>(proofRecord.ProofJson);
        bool verified = false;
        switch (request.Name)
        {
            case "ProveYourFirstName":
                verified = VerifyFirstName(proof, model.HolderFirstName); break;
            default:
                    break;
        }
        if (!verified)
        {
            proofRecord.State = ProofState.Rejected;
            await _walletRecordService.UpdateAsync(agentContext.Wallet, proofRecord);
        }

        return RedirectToAction("Index");
    }

    public bool VerifyFirstName(PartialProof proof, SendNameRequestViewModel model.HolderFirstName)
    {
        var firstName = model.HolderFirstName;
        var name = proof.RequestedProof.RevealedAttributes.First();
        if (name.Value.Raw.Equals(firstName))
        { 
            return true; 
        }

        return false;
    }

Answer 1

First of all, the actions/methods in the controller class are meant to handle requests coming from the client to the server. They're not just methods in a class.

Hence I think you need to take out out keyword from the parameter holderFirstName. Or better, to use a view model to pass between the view and the controller:

public class SendNameRequestViewModel
{
    [Required]
    public string ConnectionId { get; set; }

    [Required]
    public string HolderFirstName { get; set; }
}

public class ProofController : Controller
{
    public async Task<IActionResult> SendNameRequest(string connectionId)
    {
        // Initialize the view model if needed, i.e., filling its ConnectionId either
        // from query string or cache. I don't know how you get the connectionId

        var agentContext = await _agentProvider.GetContextAsync();
        var connectionRecord = await _walletRecordService.GetAsync<ConnectionRecord>(agentContext.Wallet, connectionId);
        if (connectionRecord == null)
        {
            return NotFound();
        }

        var vm = new SendNameRequestViewModel
        {
            ConnectionId = connectionId
        };
        return View(vm);
    }
}

Then on the view, you declare its model as SendNameRequestViewModel so that you don't have to hard code the input names/

Notes: I've also added validation summary and validation message for inputs.

@model SendNameRequestViewModel

...

<form class="input-group mb-3" method="post" asp-controller="Proof" asp-action="SendNameRequest">
    <input type="hidden" asp-for="ConnectionId" />

    <div asp-validation-summary="ModelOnly"></div>

    <input asp-for="HolderFirstName" autocomplete="off" class="form-control" 
      placeholder="Enter First Name" aria-label="First Name" aria-describedby="basic-addon2">
    <span asp-validation-for="HolderFirstName" class="text-danger"></span>

    <div class="input-group-append">
        <button class="btn btn-outline-info" type="submit">Request a Proof of First Name</button>
    </div>
</form>

For your VerifyFirstName check, there are so many way to do it. You can directly run its logic in the controller action body, for example. I would create an extension method against PartialProof object:

public static class PartialProofExtensions
{
    public static bool VerifyFirstName(this PartialProof proof, string firstName)
    {
        if (proof == null)
        {
            return false;
        }

        var name = proof.RequestedProof.RevealedAttributes
            .FirstOrDefault();

        return (name != null && name.Value.Raw.Equals(firstName));
    }
}

When the form is posting back, you can just run the validation check in the action method:

[HttpPost]
[ValidateAntiforgeryToken]
public async Task<IActionResult> SendNameRequest(SendNameRequestViewModel model)
{
    if (ModelState.IsValid)
    {
        var agentContext = await _agentProvider.GetContextAsync();
        var connectionRecord = await _walletRecordService.GetAsync<ConnectionRecord>(agentContext.Wallet, model.ConnectionId);
        if (connectionRecord == null)
        {
            ModelState.AddModalError("", "Invalid connection Id.");
            return View(model);
        }

        var proofNameRequest = await CreateProofNameMessage(connectionRecord);
        if (!proofNameRequest.VerifyFirstName(model.HolderFirstName))
        {
            ModelState.AddModalError(nameof(model.HolderFirstName), "Invalid first name.");
            return View(model);
        }

        await _messageService.SendAsync(agentContext.Wallet, proofNameRequest, connectionRecord);

        return RedirectToAction("Index");
    }

    return View(model);
}