Rick Strahl's Web Log

Rick Strahl's Web Log

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

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WPF Hanging in Infinite Rendering Loop

Yesterday - 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

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.

Back to Basics: Non-Navigating Links for JavaScript Handling

5 comments

January 21, 2019 - Maui, Hawaii

When you're creating HTML Anchor links that are non-navigating and handled via script code or through some JavaScript framework, what's the best way to handle the `HREF` navigation link in the HTML? In this back to basics post I look at a few different approaches and what works best.

A Visual Studio to Visual Studio Code Snippet Converter

1 comment

January 14, 2019 - Maui, Hawaii

Visual Studio Code Snippets are very useful and a great productivity enhancing tool for templating reusable code blocks into the editor. I have tons of snippets I use all the time for great productivity savings. Over the last couple of years I've been increasingly using Visual Studio Code and JetBrains Rider and I found myself missing my nearly 150 code snippets from Visual Studio, so I created a small hacky utility to move code snippets from Visual Studio to VS Code and with more limited features to Rider.

Don't let ASP.NET Core Console Logging Slow your App down

2 comments

December 31, 2018 - Maui, Hawaii

Today I ran into a self-inflicted problem with Console logging while playing with a toy test project. By accident I ran the application under load and Console Logging was on and performance was horrendous. In fact nearly 40x slower horrendous. Although my error, there are a few ways this can happen and it's important to understand that Console logging is very, very slow and in this post I show how this happened and why you want to be careful with Console logging in production.

Updating Westwind.AspnetCore.Markdown with Markdown from Files and URLs

December 20, 2018 - Maui, Hawaii

In the last week I've had a need to add some additional features to my Westwind.AspnetCore.Markdown library that provide easier access to Markdown from files and urls as well as the ability to replace the default Markdown parser in the library. In this post I'll discuss some of the feature additions including some implementation notes.

Returning an XML Encoded String in .NET

November 30, 2018 - Maui, Hawaii

XML is not as popular as it once was, but there's still a lot of XML based configuration and data floating around today. Today I ran into a recurring issue where I needed to convert a string to a properly encoded XML string. Seems simple enough but it's not as straightforward as you might think to generate an XML Encoded string properly. This post shows a few different ways to retrieve a string and discusses advantages of each.

Creating a .NET Global Tool from an existing Console Application

2 comments

November 05, 2018 - Maui, Hawaii

.NET Core doesn't support creating executables directly, but it does have support for **Global Tools** which provide a mechanism to register a console application and make it easily accessible using a simple command line command rather than a complex `dotnet.exe` command.

Creating an HTML Packager

November 01, 2018 - Maui, Hawaii

Recently I needed to add the ability to save HTML documents in Markdown Monster. Saving raw rendered Markdown is not really sufficient and so I set out to create an HTML packager that can package an HTML Web endpoint into a self-contained local package either as a single self-contained file, or an HTML document with all dependencies localized. In this post I discuss why this is needed and how to implement and use this library to capture HTML output in a few different ways.

Slow Connections with Sql Server

5 comments

October 26, 2018 - Maui, Hawaii

Ran into a problem with extremely slow SQL Server connections when connecting to the server. Connections would take 2 seconds or more even on repeat connections. It turns out the problem is related to missing TCP/IP protocol support which is disabled by default.

Tip: Open Visual Studio Code from Visual Studio as an External Tool

5 comments

October 06, 2018 - Maui, Hawaii

I use both Visual Studio and Visual Studio Code in my development. Although I tend to still default to the full version of Visual Studio, I tend to run Visual Studio Code side by side with Visual Studio and flip back and forth a lot. To make things a little easier and being able to jump directly to a document in VS Code from full VS you can create an External Tool entry and a shortcut mapping to quickly open documents and/or folders in VS Code.

Getting around Chrome POST XSS Protection

September 22, 2018 - Maui, Hawaii

Ran into an unusual issue where Chrome is blocking user input from a TextArea that includes HTML form and input control input - on the client side. While I'm familiar with server side input validation, this is client side validation that causes the response to be rejected. Here's more info on the error and how to get around it when necessary.

Markdown and Cross Site Scripting

4 comments

August 31, 2018 - Hood River, Oregon

I've been getting a number of requests for providing XSS support in my various Markdown components. While Markdown itself makes no provision for HTML Sanitation, if you use Markdown for capturing user input some sort of sanitation is required to avoid potential XSS attacks. In this post I look at XSS scenarios and show how the `Westwind.AspnetCore.Markdown` package deals with removing script tags from rendered Markdown content.

Fixing Visual Studio Intellisense Errors

3 comments

August 07, 2018 - Hood River, Oregon

I ran into a problem in one of my applications where Visual Studio was showing errors that were clearly not actual errors. A new feature in Visual Studio now shows separate error listings for Build and IntelliSense errors and it turns out the errors are Intellisense errors. Here's how to fix them and get Visual Studio back onto the straight and narrow.

Web Assembly and Blazor: Re-assembling the Web

25 comments

July 31, 2018 - Hood River, Oregon

Web Assembly is changing the way we think about Web development with new ideas and approaches that may not involve JavaScript. Microsoft has put its foot forward with a new Web Assembly based framework called Blazor that combines Razor templates with C# code to provide a rich .NET based front end experience. There's much to think about and understand in this still experimental framework, but the concepts it presents provide a welcome change to the JavaScript status quo. In this post I examine how Web Assembly and Blazor interact, how .NET code is used and give some thoughts on how this technology fits into the Web stack.

Creating a WPF ItemSource Length Filter Converter

3 comments

June 23, 2018 - Hood River, Oregon

In this short post I show you you can create a simple Value Converter to limit the max number of items in an ItemsSource value binding in WPF.

Explicitly Ignoring Exceptions in C#

16 comments

June 16, 2018 - Hood River, Oregon

In most applications I have a few places where I explicitly need to ignore errors. While generally this isn't a good idea, under some circumstances you just don't care if an error occurs or you simply want a yay or nay response. In this stupid pet tricks post, I describe a few scenarios where not catching any exceptions makes sense along with a couple of helper methods that make these scenarios more explicit so code analyzer and book thrower reviewers can be quieted down.

Which .NET Core Runtime Download do you need?

4 comments

June 05, 2018 - Hood River, Oregon

.NET Core has a number of different runtime downloads that you can grab to install. The combinations of downloads can be a bit confusing and it depends on whether you install a development or runtime environment. In this post I describe what each download contains and what you should use it for.

Web Code is a solved Problem: How about fixing Web UI next?

27 comments

May 31, 2018 - Hood River, Oregon

These days most of the focus in Web development is on code - JavaScript code in particular. By comparison, the Web UI - HTML and CSS and the browser DOM and support features - feels like it has been stuck in the mud and stagnating for a long time. We now have all the advanced coding tools to do cool stuff, but it seems that HTML and the Web Browser's feature set are really what is holding us back. In this post I look at what's ailing Web UI and try to ruffle some feathers into discussion of how we can affect more rapid change in Web UI features.

Updating my AlbumViewer to ASP.NET Core 2.1 and Angular 6.0

9 comments

May 09, 2018 - Hood River, Oregon

Took some time to upgrade my AlbumViewer application to ASP.NET Core 2.1 RC and Angular 6.0. The .NET Core update was very smooth with only very minor adjustments required showing that Microsoft has smoothed out the update path significantly from the frenetic pace of past versions. The Angular update was a bit more involved primarily due to the changes in rxJS.

Creating a generic Markdown Page Handler using ASP.NET Core Middleware

April 18, 2018 - Maui, Hawaii

I've been talking about Markdown a lot in recent blog posts and this time I'll cover a generic Markdown page handler that you just drop into any site to handle semi-static page editing more easily with Markdown from within an ASP.NET Core application. While Markdown is common fare in CMS or blog applications, it's not so apparent how to get similar generic Markdown document rendering within the context of an existing application. The middleware I describe here allows you to simply drop a markdown file into a configured folder and have it rendered into a stock template. Simple but very useful.

Getting the .NET Core Runtime Version in a Running Application

6 comments

April 12, 2018 - Maui, Hawaii

Microsoft has a long history of not providing a reasonable way of looking up the version of the runtime that is hosting your applications. .NET Core is no different and in this short post I show one way you can capture a descriptive name of the runtime executing that's suitable for displaying in your application's info page.

Creating an ASP.NET Core Markdown TagHelper and Parser

3 comments

March 23, 2018 - Maui, Hawaii

A couple of months ago I wrote about creating a WebForms based Markdown control. This time around I'll build an ASP.NET Core MVC TagHelper that performs similar functionality for embedding Markdown text into a content area of a Razor page. The component also includes easy access to a Markdown parser using the blazing fast MarkDig Markdown parser.