Skip to main content

C# Type Inference In Generic Methods + Leveraging that from Extension Methods – A Quick Note

This is a back to basics post.

As you may already know, C# compiler don’t support type inference for generic classes, but it supports type inference for generic methods. To illustrate the point, let us consider a very simple example.

class Program
    {
        //Our generic IsGreaterThan method
        public static bool IsGreaterThan<T>(T x, T y) where T : IComparable<T>
        {
            return (x.CompareTo(y) > 0);
        }

        static void Main(string[] args)
        {
            //You don't need to explicitly specify IsGreaterThan<int>
            var result = IsGreaterThan(20,10);
            Console.WriteLine(result); 
        }

    }

As you can see, we are not specifying the type explicitly, while calling our IsGreaterThan method - it is inferred automatically by the compiler. That is simple, isn’t it? Now, things become a a bit more interesting when you combine Generic method type inference with extension methods. Have a look at this code, we just made our IsGreaterThan<T> method an extension method.

  public static class UtilExtensions
    {
        //Our generic IsGreaterThan extension method
        public static bool IsGreaterThan<T>(this T x, T y) where T : IComparable<T>
        {
            return (x.CompareTo(y) > 0);
        }      
    }
    
    class Program
    {
        static void Main(string[] args)
        {
            //You still don't need to explicitly specify IsGreaterThan<int>
            var result = 20.IsGreaterThan(10);
            Console.WriteLine(result);

        }

    }

As you can see, we are still good - the compiler can still infer the types. And of course, you can leverage our IsGreaterThan against any IComparable implementation. Also, explore more back to basics posts.

Popular posts from this blog

Creating a quick Todo listing app on Windows using IIS7, Node.js and Mongodb

As I mentioned in my last post, more and more organizations are leaning towards Web Oriented Architecture (WOA) which are highly scalable. If you were exploring cool, scalable options to build highly performing web applications, you know what Node.js is for.After following the recent post from Scott Hanselman, I was up and running quickly with Node.js. In this post, I’ll explain step by step how I’ve setup Node.js and Mongodb to create a simple Todo listing application.Setting up Node.jsThis is what I’ve done.1 – Goto http://nodejs.org/, scroll down and download node.exe for Windows, and place it in your c:\node folder2 – Goto IIS Node project in Git at https://github.com/tjanczuk/iisnode, download the correct ‘retail’ link of IIS Node zip file (I downloaded the already built retail package, otherwise you can download and build from the source).3 – Extract the zip file some where, and run the install.bat or install_iisexpress.bat depending on your IIS Version. If you don’t have IIS in…

MVVM - Binding Multiple Radio Buttons To a single Enum Property in WPF

I had a property in my View Model, of an Enum type, and wanted to bind multiple radio buttons to this.

Firstly, I wrote a simple Enum to Bool converter, like this.

public class EnumToBoolConverter : IValueConverter { #region IValueConverter Members public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { if (parameter.Equals(value)) return true; else return false; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { return parameter; } #endregion }

And my enumeration is like

public enum CompanyTypes { Type1Comp, Type2Comp, Type3Comp } Now, in my XAML, I provided the enumeration as the ConverterParameter, of the Converter we wrote earlier, like
<Wi…

Top 7 Coding Standards & Guideline Documents For C#/.NET Developers

Some time back, I collated a list of 7 Must Read, Free EBooks for .NET Developers, and a lot of people found it useful. So, I thought about putting together a list of Coding Standard guidelines/checklists for .NET /C# developers as well.As you may already know, it is easy to come up with a document - the key is in implementing these standards in your organization, through methods like internal trainings, Peer Reviews, Check in policies, Automated code review tools etc. You can have a look at FxCop and/or StyleCop for automating the review process to some extent, and can customize the rules based on your requirements.Anyway, here is a list of some good Coding Standard Documents. They are useful not just from a review perspective - going through these documents can definitely help you and me to iron out few hidden glitches we might have in the programming portion of our brain. So, here we go, the listing is not in any specific order.1 – IDesign C# Coding StandardsIDesign C# coding stand…