System.InvalidOperationException: Headers are read-only, response has already started.
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpHeaders.ThrowHeadersReadOnlyException()
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpResponseHeaders.Microsoft.AspNetCore.Http.IHeaderDictionary.set_ContentType(StringValues value)
   at Microsoft.AspNetCore.Http.DefaultHttpResponse.set_ContentType(String value)
   at Microsoft.AspNetCore.Mvc.Formatters.OutputFormatter.WriteResponseHeaders(OutputFormatterWriteContext context)
   at Microsoft.AspNetCore.Mvc.Formatters.TextOutputFormatter.WriteAsync(OutputFormatterWriteContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ObjectResultExecutor.ExecuteAsyncCore(ActionContext context, ObjectResult result, Type objectType, Object value)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ObjectResultExecutor.ExecuteAsync(ActionContext context, ObjectResult result)
   at Microsoft.AspNetCore.Mvc.ObjectResult.ExecuteResultAsync(ActionContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeResultAsync>g__Logged|22_0(ResourceInvoker invoker, IActionResult result)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|30_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeAlwaysRunResultFilters()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|25_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Als.ALSolutions.WebSite.Startup.<>c__DisplayClass13_0.<<Configure>b__3>d.MoveNext() in C:\ALS_Git\ALSolutions V2\ALSolutions_V2\Als.ALSolutions.WebSite\Startup.cs:line 615

Application: Telerik.ReportDesigner.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.InvalidOperationException
   at System.Windows.Forms.BindingSource.get_Count()
   ...

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE [dbo].[ProcedureConditionsTest]
@ReportPart SMALLINT = 1
AS
BEGIN
SET NOCOUNT ON;
IF @ReportPart = 1
BEGIN
SELECT P.FirstName AS FirstNamePart1, P.MiddleName AS MiddleNamePart1, P.LastName AS LastNamePart1,
	A.AddressLine1 AS AddressLine1Part1, A.AddressLine2 AS AddressLine2Part1, A.City AS CityPart1, A.PostalCode AS PostalCodePart1,
	SP.StateProvinceCode AS StateProvinceCodePart1, SP.CountryRegionCode AS CountryRegionCodePart1, SP.[Name] AS NamePart1
FROM [Person].[Person] AS P
JOIN [Person].[BusinessEntityAddress] AS BEA ON P.BusinessEntityID = BEA.BusinessEntityID
JOIN [Person].[Address] AS A ON BEA.AddressID = A.AddressID
JOIN [Person].[StateProvince] AS SP ON A.StateProvinceID = SP.StateProvinceID
WHERE P.FirstName BETWEEN 'A. Scott' AND 'Justine'
ORDER BY P.FirstName, P.LastName
END
ELSE IF @ReportPart = 2
BEGIN
SELECT P.FirstName AS FirstNamePart2, P.MiddleName AS MiddleNamePart2, P.LastName AS LastNamePart2,
	A.AddressLine1 AS AddressLine1Part2, A.AddressLine2 AS AddressLine2Part2, A.City AS CityPart2, A.PostalCode AS PostalCodePart2,
	SP.StateProvinceCode AS StateProvinceCodePart2, SP.CountryRegionCode AS CountryRegionCodePart2, SP.[Name] AS NamePart2
FROM [Person].[Person] AS P
JOIN [Person].[BusinessEntityAddress] AS BEA ON P.BusinessEntityID = BEA.BusinessEntityID
JOIN [Person].[Address] AS A ON BEA.AddressID = A.AddressID
JOIN [Person].[StateProvince] AS SP ON A.StateProvinceID = SP.StateProvinceID
WHERE P.FirstName BETWEEN 'K.' AND 'Zoe'
ORDER BY P.FirstName, P.LastName
END
END
GO

EXEC [dbo].[ProcedureConditionsTest]
@ReportPart = 1

EXEC [dbo].[ProcedureConditionsTest]
@ReportPart = 2