How to execute query in C # for request control

I'm new to programming and need to add some functionality in a C # asp.net application. One is a control that prevents the user from proceeding with the request if it has any pending on the system. I'll describe it step by step.

My view

@using Integracao.ImpressoRequests.Model.Entities.ImpressoRequest
@model Request
@{
  ViewBag.Title = "Requisição";
  Layout = "~/Views/Shared/_Layout.cshtml";
}

    ...

    @foreach (RequestItem item in Model.Items)
    {
        <tr>
            <td>
                @Html.DisplayFor(x => item.Usuario.Nome)
            </td>
            <td>
                @Html.DisplayFor(x => item.Date)
            </td>
            <td>
                @Html.DisplayFor(x => item.Unidade.Nome)
            </td>
            <td>
                @Html.DisplayFor(x => item.ResultCenter.Nome)
            </td>
        </tr>
    }
</table>
<div class="formfooter">

    <input type="button" value="Gerar pedido" onclick="window.open('@Url.Action("ProcessRequest", new { requestId = Model.Id })','_blank');window.location.href='@Url.Action("Index", "Home")'" /></div>

Controller

    [HttpGet]
    public ActionResult ProcessRequest(int requestId)
    {
        Request request = _data.Requests.GetByID(requestId);
        if (request.Processed)
            return RedirectToAction("PrintRequest", new { requestId = request });
        foreach (RequestItem item in request.Items.OrderBy(x => x.Usuario_Id))
        {
            AssignImpressos assignIItems = new AssignImpressos(item.Id);
            assignIItems.Assign();
        }
        request.Processed = true;
        _data.Save();
        return RedirectToAction("PrintRequest", new { requestId = request.Id });
    }

Model

    public Request()
    {
        Date = DateTime.Now;
        UsedItems = new List<Impresso>();
        RequestsHistory = new List<RequestHistory>();
        Items = new List<RequestItem>();
    }

    public int Id { get; set; }

    public DateTime? Date { get; set; }

    public string Justification { get; set; }

    public string Usuario_Id { get; set; }

    public virtual Usuario Usuario { get; set; }
    public virtual ICollection<Impresso> UsedItems { get; set; }

    Model Impresso

        public class Impresso : IEntity
{
    public Impresso()
    {
        RequestsHistory = new List<RequestHistory>();
    }

    public int Id { get; set; }

    public int Code { get; set; }

    public string Purpose { get; set; }

    public DateTime? Data_Controle { get; set; }

    public decimal AdjustedValue { get; set; }

    public int Status { get; set; }
    public ItemStatus EnumeratedStatus
    {
        get { return (ItemStatus)Status; }
        set { Status = (int)value; }
    }        
    public string Note { get; set; }

    public string Usuario_Id { get; set; }
    public virtual Usuario Usuario { get; set; }

    public int? Request_Id { get; set; }
    public virtual Request Request { get; set; }

    public string Unidade_Id { get; set; }
    public virtual Unidade Unidade { get; set; }

    public string ResultCenter_Id { get; set; }
    public virtual ResultCenter ResultCenter { get; set; }

    public virtual ICollection<RequestHistory> RequestsHistory { get; set; }

    object IEntity.Id
    {
        get { return Id; }
        set { Id = (int)value; }
    }
}

What I need is the following: When the user clicks 'Generate Order' in the view, in my controller class I need to scan the Order table in the database, looking for if that user already authenticated by the system has in the printed table the 'Data_Controle' null or Status = 1. If positive, the system should prevent the continuation by triggering an alert with the information. If false, the program continues and generates the request normally. The question is, I know how to select one in the bank to get it but what the syntax in C # according to my code to make this control? I thought of query because I move with database and the logic is clearer for me, or if not for query, what would be the best way to achieve this in logic programming? Thanks

Edit

        private string GetUser()
    {
        string userId = string.Empty;
        try
        {
            string id = User.Identity.Name.Split('\')[1];
            Usuario _currentUsuario = _data.Usuario.GetByID(id);
            userId = _currentUsuario.Id;
            ViewBag.UserName = _currentUsuario.Name;
        }
        catch (Exception ex)
        {
            ModelState.AddModelError("UserName", ex.Message);
        }
        return userId;
    }