Category Archives: web

Graph currency rates over time in C#

This example, which shows how to graph currency rates for a specific currency, is a bit longish. Sorry about that. It uses Yahoo Query Language (YQL), which you can use to perform a wide variety of queries on Yahoo’s data. … Continue reading

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Get currency exchange rates in C#

This example shows how you can get currency exchange rates from finance.yahoo.com. When it starts, the program uses the following code to get the currency exchange rates. // Get the currency symbols. private void Form1_Load(object sender, EventArgs e) { string … Continue reading

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Get stock prices from different exchanges in C#

The example Get stock prices from the internet in C# shows how to download stock prices from download.finance.yahoo.com. It builds a URL of the following form to get prices for MCI, DIS, COKE, and PEP: http://download.finance.yahoo.com/d/quotes.csv?s=MCI+DIS+COKE+PEP&f=sl1d1t1c1 To get prices from … Continue reading

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Make a temperature forecast in C#

The example Get weather forecast data in C# explains how to read weather forecast data from OpenWeatherMap. This example uses that data to list the forecast’s temperatures. The forecast data has (in part) the following structure. <weatherdata> … <forecast> <time … Continue reading

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Get weather forecast data in C#

There are many sites that offer weather condition and weather forecast services. All of the ones I found required you to have a developer key, although most of them have a free membership that works for a simple program like … Continue reading

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Download images from a web page in C#

This is a big program and this description only touches on its most interesting parts. Download it to see the details. The program displays a WebBrowser control on the left. Click the links on the WebBrowser to navigate to a … Continue reading

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Continuously graph stock prices in C#

The example Get stock prices from the internet in C# explains how to get stock prices from the Yahoo! finance web site. This example uses similar techniques to query the site periodically and then graph stock prices. This example is … Continue reading

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Make an HTML table of thumbnail images in C#

The post Make thumbnails and a web page to display the images in a directory in C# shows how to make thumbnails for the images in a directory and then build a web page to display them. There are lots … Continue reading

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Make thumbnails and a web page to display the images in a directory in C#

This example searches a directory and makes thumbnails for each of the image files it finds there. It also builds a web page that displays the thumbnails and that includes links to the full-scale images. It puts all of the … Continue reading

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Make CAPTCHA images with overlapping characters in C#

The following MakeCaptchaImage2 method creates a Bitmap containing a CAPTCHA image. private Random Rand = new Random(); // Draw the words with letters overlapping each other. private Bitmap MakeCaptchaImage2(string txt, int wid, int hgt, Font the_font, Brush the_brush) { Bitmap … Continue reading

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