Rick Strahl's Web Log

Rick Strahl's Web Log

Wind, waves, code and everything in between...
ASP.NET • C# • HTML5 • JavaScript • AngularJs

Ad-free experience sponsored by:

ASPOSE - the market leader of .NET and Java APIs for file formats – natively work with DOCX, XLSX, PPT, PDF, images and more

Creating Angular Synchronous and Asynchronous Validators for Template Validation

November 18, 2019 - Maui, Hawaii

Validations are a key feature of any business application and in Angular there's an infrastructure for building validators built in. A number of existing validators provide the basics but if you have custom business logic to process for validation you'll need to create custom Validators. In this post I describe how to create both sync and asycn Angular Validators for use in declarative forms.

FireFox, Windows Security and Kestrel on ASP.NET Core

November 14, 2019 - Maui, Hawaii

Ran into issues today with Windows Authentication and FireFox in a ASP.NET Core application where auth was working with all browsers **except** for FireFox. Firefox would just throw up endless sequences of login dialogs or in some cases just show the default ASP.NET Core 'UnAuthenticated' dialog. Here's what this looks like and how to work around it.

Dynamically Loading Assemblies at Runtime in RazorPages

3 comments

November 05, 2019 - Maui, Hawaii

I've been working on some tools that create generic, standalone Web servers using ASP.NET Core, in various configurations. One of the versions I'm building also supports Razor Pages and while genericallly hosting Razor Pages out of a locally run folder, there are some complications that arise out of dynamic runtime compilation. In this post I look at how to dynamically load assemblies at runtime.

Windows Authentication and Account Caching on Web Browser Auto-Logins

2 comments

October 19, 2019 - Maui, Hawaii

If you're working with Windows authentication to access Windows or Active Directory groups be aware that there's a gotcha with newly added groups when users are automatically logged into the Web browser.

Serving ASP.NET Core Web Content from External Folders

2 comments

September 30, 2019 - Maui, Hawaii

ASP.NET Core makes it easy to create a new Web site, but by default the location of where the application runs and serves files from is pretty static and pinned to the startup folder of the application. In this post I discuss another usage scneario of building a generic local Web Server that can start serving files out of **any** folder.

Upgrading my AlbumViewer Sample Application to ASP.NET Core 3.0

6 comments

September 24, 2019 - Maui, Hawaii

.NET Core 3.0 is here and in this post I describe the process of updating an existing ASP.NET Core Angular API application to this latest release. For the most part the update process is very smooth with a few configuration changes required, but there are also a few gotchas that have bitten me and I'll cover those here.

Open Internet Settings Dialog directly on Windows

2 comments

September 10, 2019 - Maui, Hawaii

Windows is making it harder to find classic Control Panel windows and the Internet Settings dialog is no exception. The Networking options no longer have a link to it, so you have remember where to look for it. Here's a quick way to get to it.

Programmatically Opening Windows Terminal in a Specific Folder

September 03, 2019 - Maui, Hawaii

The new Windows Terminal provides many cool new features and much improved Terminal performance which makes it very desirable to use even in its current preview state. However, unfortunately the Terminal currently lacks a command line interface to control startup, do if you want to externally launch a shell some workarounds are required to get it to start out of a specific folder.

WPF Window Closing Errors

September 02, 2019 - Maui, Hawaii

I've recently had a large uptick of errors in my Markdown Monster logs that complain about `Cannot set Visibility to Visible or call Show, ShowDialog, Close, or WindowInteropHelper.EnsureHandle while a Window is closing`. This error can crop up with nested or parallel window closing operations, which might not always be obvious when they happen. I'll show some of the issues and the hacky by easy to implement work around.

Visual Studio 2019.2 and .NET 3.0 SDK Projects not Loading

August 21, 2019 - Maui, Hawaii

Recent upgrades to Visual Studio 2019.2 seem to have broken projects that use the 3.0 .NET SDK as Visual Studio is defaulting to a pre-3.0 version of the SDK tools and compilers. The end result is that projects even fail to load in Visual Studio. There are workarounds but ultimately this an issue that Microsoft needs to address better in future updates.

Uri.AbsoluteUri and UrlEncoding of Local File Urls

August 20, 2019 - Maui, Hawaii

Ran into an interesting problem with the Uri class and local file URLs today. The problem is that Urls were not properly Url encoding and decoding with the Url treated incorrectly. After a bit of experimenting it turns out that the way the file URL is created is critical to the Url parsing behavior of the Uri class.

Building a Live Reload Middleware Component for ASP.NET Core

2 comments

June 03, 2019 - Maui, Hawaii

In my last way I showed how to use Live Reload in ASP.NET Server side applications using a tool called BrowserSync. In this post I replace BrowserSync's functionality with a custom Live Reload Middleware component for ASP.NET Core that's more efficient and doesn't require installing and running a separate tool. I'll show how Live Reload works, and how to implement the component in some detail.

Live Reloading Server And Client Side ASP.NET Core Apps

6 comments

May 18, 2019 - Maui, Hawaii

Client side live reloading is one of the most compelling features of client side JavaScript development. Instant updates of any code changes in the browser are a huge productivity booster - WYSIWYG on steroids. Unfortunately for ASP.NET Core server side code and MVC apps there aren't any comparable easy solutions. In this post I show how I use Browser Sync and `dotnet watch` in combination to provide live reloading for both server and client side changes.

Accessing RouteData in an ASP.NET Core Controller Constructor

4 comments

May 15, 2019 - Maui, Hawaii

Ran into a difficulty trying to get access to RouteData() generically outside of Controller code in ASP.NET Core. Specifically I needed to get at route data to pull out a tenant ID required to set up a DbContext with the right connection string to connect to. Getting the route data as part of the DI process in the Controller constructor proved to be challenging. In this post I describe the problem and the work around.

.NET Core 3.0 SDK Projects: Controlling Output Folders and Content

7 comments

April 30, 2019 - Maui, Hawaii

I've been upgrading Markdown Monster to run on .NET Core 3.0 and one of the biggest changes is switching to the new .NET SDK style format for all projects. I ran into some issues with the Addin projects that require that output is placed in a very specific output folder and to not include output of all references. In this post describe a couple of ways to control where output goes and how to limit the output that goes to those folders.

First Steps in porting Markdown Monster WPF App to .NET Core 3.0

9 comments

April 24, 2019 - Maui, Hawaii

I spent a good part of the day today getting Markdown Monster to run on .NET Core 3.0 and in this post I packaged up my notes into a lengthy post with how went through this process. It wasn't exactly quick to make this happen but MM has a few peculiarities that made this process a little bit more trying than it could have been. I'll summarize some thoughts at the end on both the process and the relevance of this process.

Adventures in .NET Core SDK Installation: Missing SDKs and 32 bit vs 64 bit

4 comments

April 20, 2019 - Maui, Hawaii

Ran into a problem yesterday with a new installation of the .NET Core 3.0 Preview 4 installation. Installed the new preview and found that all of my .NET Core 2.x SDKs were no longer showing. A lot of back and forth later I found that I accidentally installed the wrong bitness SDK - 32 bit vs 64 bit. Here's a quick overview of how and why and why you probably NEVER want to install the 32 bit SDK.

Using the ng-BootStrap TypeAhead Control with Dynamic Data

1 comment

April 08, 2019 - Maui, Hawaii

I recently swapped my Auto complete logic in an application to use ng-bootstrap's nice and relatively easy to use TypeAhead control and I ran into a small snag trying to figure out how to bind dynamic data retrieved from the server. The examples show local data binding but fail to show how to load and update the control with remote data. In this post I show how the control works both in sync and async mode and point out the simple solution that eluded my via the Observable switchMap operator.

Creating a custom HttpInterceptor to handle 'withCredentials' in Angular 6+

3 comments

April 07, 2019 - Maui, Hawaii

Client HTTP requests often need to set a few common settings and you don't want to set them on every request. To make this process easier Angular provides an HttpInterceptor class that you can subclass and add custom behavior to for each HTTP request that is sent through the HttpClient. Here's a quick review on how to do this.

ASP.NET Core In Process Hosting on IIS with ASP.NET Core

43 comments

March 16, 2019 - Maui, Hawaii

In version 2.2 ASP.NET Core adds support for direct in-process hosting which improves throughput considerably using an easy mechanism that allows switching between in-process and out-of-process hosting. In this post I describe how to use in process hosting and how it works.

Using .NET Standard with Full Framework .NET

10 comments

February 19, 2019 - Maui, Hawaii

Using .NET Standard on full .NET Framework is a mixed bag because the behavior of .NET Standard differs depending on which version of the Runtime you are integrating with. In this post I review what .NET Standard is and how it fits in with the full .NET Framework and how you can use .NET Standard packages/assemblies in full framework along with some of the problems you have to watch out for.

WPF Hanging in Infinite Rendering Loop

3 comments

February 14, 2019 - Maui, Hawaii

Ran into a nasty WPF bug this week with Markdown Monster that caused MM to hang during startup in certain scenarios. Several users reported issues that I could not duplicate until I started playing around with my screen resolution and scaling. An obscure but insidious WPF bug can cause an application to go into an infinite loop which effectively locks up the application's UI and the app overall. Here's more info on what the problem is and how to work around it.

Ad Blockers, Brave Browser and BrainTree Credit Card Processing SDKs

2 comments

February 08, 2019 - Maui, Hawaii

Ran into an issue with my CC processing forms using Brave today. Brave is a Chromium based browser, but it includes built-in, on-by-default content blocking which apparently causes my order forms to not work as scripts and related page cookies aren't being loaded. Here's what happened and some thoughts on how to work around this.

Finding the ProgramFiles64 Folder in a 32 Bit App

1 comment

February 05, 2019 - Maui, Hawaii

.NET has the `System.GetFolderPath()` method to let you easily retrieve various system folder in a safe way. Unfortunately getting the `Program Files` folder is a bit of problem due to some complications on how the name is retrieved on 32 bit systems. If you're running an application in 32 bit mode, or have an application that can run either 32 or 64 bit, make sure you use the right way to determine where Program Files is located.

COM Object Access and dynamic in .NET Core 2.x

3 comments

January 22, 2019 - Maui, Hawaii

I was surprised to find out that COM Interop works in .NET Core when running on Windows. It's possible to access COM components via Reflection easily enough in .NET Core 2.x. Unfortunately use of the `dynamic` keyword does not work in .NET Core 2.x so for the moment COM interop is limited to using Reflection.