找不到空引用异常 [重复]

问：

我有另一个项目，其设置几乎完全相同，工作正常。我不知道这个空引用是从哪里来的。当我设置断点并在 VS 中查看它们时，签名中没有一个变量是空的。

调用堆栈

ReportBuilder.Application.dll！ReportBuilder.Application.Templates.TemplateHelper.GetTemplateReport（System.Collections.Generic.IEnumerable template， int fiscalYear， int period， System.Threading.CancellationToken cancellationToken） 第 40 行 C# ReportBuilder.API.dll！ReportBuilder.API.Controllers.TemplateController.GetTemplateReport（int FiscalYear， int Period， System.Collections.Generic.IEnumerable Sites， System.Threading.CancellationToken cancellationToken） 第 39 行 C# [轻量级功能]
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute（Microsoft.AspNetCore.Mvc.Infrastructure.IActionResultTypeMapper 映射器， Microsoft.Extensions.Internal.ObjectMethodExecutor executor， 对象控制器， object[] 参数） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync.__Logged|12_1（Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker invoker） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next（ref Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.State next， ref Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Scope scope， ref object state， ref bool isCompleted） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next（ref Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.State next， ref Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Scope scope， ref object state， ref bool isCompleted） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next（ref Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.State next， ref Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Scope scope， ref object state， ref bool isCompleted） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next（ref Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.State next， ref Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Scope scope， ref object state， ref bool isCompleted） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeNextResourceFilter（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next（ref Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.State next， ref Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Scope scope， ref object state， ref bool isCompleted） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeAsync.__Logged|17_1（Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker invoker） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeAsync（） 未知 Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Routing.ControllerRequestDelegateFactory.CreateRequestDelegate.AnonymousMethod__0（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Routing.dll！Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext httpContext） 未知 服务器共享.dll！Server.Shared.Services.RequestLogContextMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Authorization.Policy.dll！Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Authentication.dll！Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Routing.dll！Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext httpContext） 未知 Microsoft.AspNetCore.StaticFiles.dll！Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Http.Abstractions.dll！Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Http.Abstractions.dll！Microsoft.AspNetCore.Builder.UseExtensions.Use.AnonymousMethod__2（） 未知 服务器共享.dll！Server.Shared.Services.ServiceExtensions.AddSharedConfiguration.AnonymousMethod__4_2（Microsoft.AspNetCore.Http.HttpContext 上下文、System.Func<System.Threading.Tasks.Task> next） 未知 Microsoft.AspNetCore.Http.Abstractions.dll！Microsoft.AspNetCore.Builder.UseExtensions.Use.AnonymousMethod__1（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.HttpsPolicy.dll！Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.StaticFiles.dll！Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.StaticFiles.dll！Microsoft.AspNetCore.StaticFiles.DefaultFilesMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Diagnostics.dll！Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Http.Abstractions.dll！Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Diagnostics.dll！Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.ResponseCompression.dll！Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.InvokeCore（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.ResponseCompression.dll！Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.StaticFiles.dll！Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Swashbuckle.AspNetCore.SwaggerUI.dll！Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext httpContext） 未知 Swashbuckle.AspNetCore.Swagger.dll！Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext httpContext， Swashbuckle.AspNetCore.Swagger.ISwaggerProvider swaggerProvider） 未知 Microsoft.AspNetCore.Http.Abstractions.dll！Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.UseMiddleware.AnonymousMethod__2（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Diagnostics.dll！Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.HostFiltering.dll！Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.WebTools.BrowserLink.Net.dll！Microsoft.WebTools.BrowserLink.Net.BrowserLinkMiddleware.InvokeAsync（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.WebTools.BrowserLink.Net.dll！Microsoft.WebTools.BrowserLink.Net.VsContentMiddleware.InvokeAsync（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Watch.BrowserRefresh.dll！Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware.InvokeAsync（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Http.Abstractions.dll！Microsoft.AspNetCore.Builder.Extensions.MapWhenMiddleware.Invoke（Microsoft.AspNetCore.Http.HttpContext context） 未知 Microsoft.AspNetCore.Hosting.dll！Microsoft.AspNetCore.Hosting.HostingApplication.ProcessRequestAsync（Microsoft.AspNetCore.Hosting.HostingApplication.Context context） 未知 Microsoft.AspNetCore.Server.IIS.dll！Microsoft.AspNetCore.Server.IIS.Core.IISHttpContextOfT<Microsoft.AspNetCore.Hosting.HostingApplication.Context>。ProcessRequestAsync（） 未知 Microsoft.AspNetCore.Server.IIS.dll！Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.HandleRequest（） 未知 Microsoft.AspNetCore.Server.IIS.dll！Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.Execute（） 未知 System.Private.CoreLib.dll！System.Threading.ThreadPoolWorkQueue.Dispatch（） 未知 System.Private.CoreLib.dll！System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart（） 未知 System.Private.CoreLib.dll！System.Threading.Thread.StartCallback（） 未知 调用堆栈

public async Task<byte[]> GetTemplateReport(IEnumerable<long> template, int fiscalYear, int period, CancellationToken cancellationToken = default)
    {
        Console.WriteLine("");
        return await _ReportHelper.GetReportBytes(new TemplateReport(fiscalYear, period, template, _Mediator), cancellationToken);
    }

public async Task<byte[]> GetReportBytes(IReport report, CancellationToken cancellationToken = default(CancellationToken))
        {
            IReport report2 = report;
            IReportBuilder reportBuilder = _ReportBuilder;
            reportBuilder.SetData(await report2.GetReportData(cancellationToken));
            TemplateBuilder templateBuilder = new TemplateBuilder();
            templateBuilder.GetReportOptions(report2.GetReportOptions(new ReportOptions()));
            templateBuilder.SetReportHeaders(report2.GetReportHeaders(new List<ReportHeader>()));
            foreach (ReportColumnSection reportColumnSection in report2.GetReportColumnSections(new ReportColumnSectionsBuilder()))
            {
                templateBuilder.AddColumnSection(reportColumnSection);
            }

            foreach (ReportRowSection reportRowSection in report2.GetReportRowSections(new ReportRowSectionsBuilder()))
            {
                templateBuilder.AddReportSection(reportRowSection);
            }

            templateBuilder.SetRowFormulas(report2.GetRowFormulas(new List<RowFormulaConfig>()));
            _ReportBuilder.SetConfiguration(templateBuilder.Build());
            _ReportBuilder.SetFinalizeCallBack(delegate (IWorksheet x)
            {
                report2.ReportFinalize(x);
            });
            return _ReportBuilder.BuildByteArray();
        }

using ReportBuilder.Application.Templates.Queries;
using GrapeCity.Documents.Excel;
using MediatR;
using Reporting.Shared;

namespace ReportBuilder.Application.Templates.Reports;
public class TemplateReport : IReport
{
    private readonly IMediator _Mediator;
    private int FiscalYear;
    private int Period;
    private IEnumerable<long> Templates = Enumerable.Empty<long>();

    public TemplateReport(int fiscalYear, int period, IEnumerable<long> templates, IMediator mediator)
    {
        _Mediator = mediator;
        FiscalYear = fiscalYear;
        Period = period;
        Templates = templates;
    }