13
DEC
.NET and Azure Developer
.NET
25
NOV
.NET Core WebUtility.UrlEncode or HttpUtility.UrlEncode
When we are dealing with URL encode in .NET Core 2.1, there are two APIs: System.Net.WebUtility.UrlEncode and System.Web.HttpUtility.UrlEncode. What's the difference between them? And which one should we prefer to use? I have done some research today, here's my findings. 1. Test Results First, let's see some tests. I've tested 2 couples of the same method between WebUtility class and HttpUtility …
31
OCT
Migrating Old ASP.NET Applications to .NET Core
More and more people are talking about .NET Core these days. It is true that .NET Core is the future, and .NET Framework will still be maintained because very large number of applications can’t be migrated in a short time. .NET Core and .NET Framework are just like electric cars and gasoline powered cars. Gasoline cars is mature, and you can drive it without any problem, but electric cars have …
13
OCT
Generate Captcha Code in ASP.NET Core
If you want to use captcha code to protect your website from spam messages, there are a few options such as Google ReCaptcha and captcha.com. Both of them can be integrated into ASP.NET Core applications. However, you may still want to generate the captcha code yourself for some reason, such as your website may be used in mainland China... This post will show you how to generate and use captcha …
12
OCT
Add Watermark to Uploaded Image in ASP.NET Core
Adding watermark to an image is very widely used in websites in order to protect the content owner's copyright, such as a blog system like this website. In traditional ASP.NET (.NET Framework), we could use System.Web.Helpers.WebImage to add text watermark like this: var image = new WebImage(imageBytes); image.AddTextWatermark( Settings.Instance.WatermarkText, "White", Settings.Instance. …
27
SEP
Get App Version in .NET Core
We can define versions on our .NET Core applications, but how to get the version at runtime? There are several ways to do it. First, let's see a typical .NET Core project file with versioning. We can define the version numbers for AssemblyVersion, FileVersion and Version in the project file (.csproj). The AssemblyVersion and FileVersion attributes must be in format of "major[.minor[.build[. …
19
SEP
Send AntiForgeryToken via jQuery Ajax in ASP.NET Core
In ASP.NET Core, if we use jQuery Ajax to post data to the server, and we want the ValidateAntiForgeryToken attribute to work. We have to do some tricks. The official document didn't document how to do it via jQuery. Let me show you how to do it. Please do read the official document first: https://docs.microsoft.com/en-us/aspnet/core/security/anti-request-forgery?view=aspnetcore-2.1 In my …
18
SEP
Prevent Image Hotlinking in ASP.NET/Core Applications
Introduction As a website developer, we sometimes don't want the images on our own website to be directly referenced and showed on other's website. It can cause a lot network bandwidth for our datacenters in some cases, which means costing money for us to pay for the one who use our images. For example, your website is A.com, you have an image on http://a.com/facepalm.jpg and B.com used your …
06
NOV
Use ICMP Ping in .NET Core 2.0
In classic .NET Framework applications, we have used System.Net.NetworkInformation.Ping class to Ping a host address. This API is not included by default in .NET Core, even in version 2.0. Here is how to do it in a .NET Core way. First, we need to reference a package System.Net.Ping Install-Package System.Net.Ping This will give us the same API set as .NET Framework. Then, in your .NET Core code, …
01
NOV