Difference Between Int32.Parse(), Convert.ToInt32(), and Int32.TryParse()

Introduction

Int32.parse(string)

Int32.Parse (string s) method converts the string representation of a number to its 32-bit signed integer equivalent. When s is a null reference, it will throw ArgumentNullException. If s is other than integer value, it will throw FormatException. When s represents a number less than MinValue or greater than MaxValue, it will throw OverflowException. For example:

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string s1 = "1234"; 
string s2 = "1234.65"; 
string s3 = null; 
string s4 = "123456789123456789123456789123456789123456789"; 

int result; 
bool success; 

result = Int32.Parse(s1); //-- 1234 
result = Int32.Parse(s2); //-- FormatException 
result = Int32.Parse(s3); //-- ArgumentNullException 
result = Int32.Parse(s4); //-- OverflowException 

Convert.ToInt32(string)

Convert.ToInt32(string s) method converts the specified string representation of 32-bit signed integerequivalent. This calls in turn Int32.Parse () method. When s is a null reference, it will return 0 rather than throw ArgumentNullException. If s is other than integer value, it will throw FormatException. When srepresents a number less than MinValue or greater than MaxValue, it will throw OverflowException. For example:

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result = Convert.ToInt32(s1); //-- 1234 
result = Convert.ToInt32(s2); //-- FormatException 
result = Convert.ToInt32(s3); //-- 0 
result = Convert.ToInt32(s4); //-- OverflowException 

Int32.TryParse(string, out int)

Int32.Parse(string, out int) method converts the specified string representation of 32-bit signed integer equivalent to out variable, and returns true if it is parsed successfully, false otherwise. This method is available in C# 2.0. When s is a null reference, it will return 0 rather than throw ArgumentNullException. If s is other than an integer value, the out variable will have 0 rather than FormatException. When s represents a number less than MinValue or greater than MaxValue, the out variable will have 0 rather than OverflowException. For example:

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 success = Int32.TryParse(s1, out result); //-- success => true; result => 1234 
 success = Int32.TryParse(s2, out result); //-- success => false; result => 0 
 success = Int32.TryParse(s3, out result); //-- success => false; result => 0 
 success = Int32.TryParse(s4, out result); //-- success => false; result => 0 

Convert.ToInt32 is better than Int32.Parse since it returns 0 rather than an exception. But again, according to the requirement, this can be used. TryParse will be the best since it always handles exceptions by itself.

What is Web API

What is Web API and why to use it ?

Asp.Net Web API is a framework for building HTTP services that can be consume by a broad range of clients including browsers, mobiles, iphone and tablets. It is very similar to ASP.NET MVC since it contains the MVC features such as routing, controllers, action results, filter, model binders, IOC container or dependency injection. But it is not a part of the MVC Framework. It is a part of the core ASP.NET platform and can be used with MVC and other types of Web applications like Asp.Net WebForms. It can also be used as an stand-alone Web services application.

Why Asp.Net Web API (Web API) ?

Today, a web-based application is not enough to reach it's customers. People are very smart, they are using iphone, mobile, tablets etc. devices in its daily life. These devices also have a lot of apps for making the life easy. Actually, we are moving from the web towards apps world.

So, if you like to expose your service data to the browsers and as well as all these modern devices apps in fast and simple way, you should have an API which is compatible with browsers and all these devices.

For example twitter,facebook and Google API for the web application and phone apps.

Web API is the great framework for exposing your data and service to different-different devices. Moreover Web API is open source an ideal platform for building REST-ful services over the .NET Framework. Unlike WCF Rest service, it use the full featues of HTTP (like URIs, request/response headers, caching, versioning, various content formats) and you don't need to define any extra config settings for different devices unlike WCF Rest service.

Web API Features

1. It supports convention-based CRUD Actions since it works with HTTP verbs GET,POST,PUT and DELETE.
2. Responses have an Accept header and HTTP status code.
3. Responses are formatted by Web API’s MediaTypeFormatter into JSON, XML or whatever format you want to add as a MediaTypeFormatter.
4. It may accepts and generates the content which may not be object oriented like images, PDF files etc.
5. It has automatic support for OData. Hence by placing the new [Queryable] attribute on a controller method that returns IQueryable, clients can use the method for OData query composition.
6. It can be hosted with in the applicaion or on IIS.
7. It also supports the MVC features such as routing, controllers, action results, filter, model binders, IOC container or dependency injection that makes it more simple and robust.

Why to choose Web API ?

1. If we need a Web Service and don’t need SOAP, then ASP.Net Web API is best choice.
2. It is Used to build simple, non-SOAP-based HTTP Services on top of existing WCF message pipeline.
3. It doesn't have tedious and extensive configuration like WCF REST service.
4. Simple service creation with Web API. With WCF REST Services, service creation is difficult.
5. It is only based on HTTP and easy to define, expose and consume in a REST-ful way.
6. It is light weight architecture and good for devices which have limited bandwidth like smart phones.
7. It is open source.