Introduction
Every time I wanted to use a weather forecast for my site, I found it too confusing. Each method I found had problems - some of the weather forecast Web services did not work properly. Eventually I noticed that Yahoo! has an RSS for its weather forecast. I decided to make a program to use that in my site and I created a class for it! I hope it will be useful for others who want to have weather forecasts in their programs.
Yahoo! Weather RSS feed
The Yahoo! Weather RSS feed enables you to get up-to-date weather information for your location. You can save this feed in My Yahoo! or your favorite feed aggregate. You can also incorporate the RSS data into your own Web site or client application. The Yahoo! Weather RSS feed is a dynamically-generated feed that is based on zip code or Location ID.
RSS Request
The Yahoo! Weather RSS feed request follows simple HTTP GET syntax: start with a base URL and then add parameters and values after a question mark (?). Multiple parameters are separated by an ampersand (&). There are two parameters for Weather RSS:
p for location u for degrees units (Fahrenheit or Celsius)
RSS Response
The Yahoo! Weather RSS feed is an XML document that conforms to RSS 2.0 specifications. RSS is an XML document containing: a single channel element representing the feed, several elements containing metadata about the feed itself, and one or more item elements describing individual items within the feed. You can find all information about these elements on the Yahoo Developer page here. As it is represented in an XML document, we can convert it to classes by XML Serialization in .NET.
Understanding XML Serialization in the .NET Framework
XML Serialization enables you to convert common language runtime objects into XML documents or streams, and vise versa. XML Serialization makes it possible to convert XML documents into such a meaningful format that all programming languages can process the converted documents without any difficulty. You don't need to know much about XML Serialization to use this code, but it can help you to change or customize it yourself.
Using the Code
Using this code is as simple as making an instance of it and then sending its required parameters (Yahoo! Weather RSS parameters) to its constructor. The first parameter is US zip code or Location ID. The second one is Units for temperature. Send "f" for Fahrenheit or "c" for Celsius and then you can use it! Like this:
Dim t As New clsWeather("JoXX" & Format(Me.ComboBox1.SelectedIndex + 1, "0000"), "c")
lblHigh.Text = t.high & "ّ"
lblCity.Text = ComboBox1.Items.Item(Me.ComboBox1.SelectedIndex) & " Weather "
lblLow.Text = t.Low & "ّ"
lblDay.Text = t.day
lblCase.Text = t.Case
lblSunrise.Text = t.Sunrise
lblSunset.Text = t.Sunset
lblWInd.Text = CInt(Val(t.Wind)) & " kph"
imgWeather.Image = Image.FromFile(t.GetImage)
