ASP.NET Web Pages - HTML Forms
A form is a section of an HTML document where you put input controls (text boxes, check boxes, radio buttons, and pull-down lists)
Creating an HTML Input Page
Razor Example
<html>
<body>
@{
if (IsPost) {
string companyname = Request["CompanyName"];
string contactname = Request["ContactName"];
<p>You entered: <br />
Company Name: @companyname <br />
Contact Name: @contactname </p>
}
else
{
<form method="post" action="">
Company Name:<br />
<input type="text" name="CompanyName" value="" /><br />
Contact Name:<br />
<input type="text" name="ContactName" value="" /><br /><br />
<input type="submit" value="Submit" class="submit" />
</form>
}
}
</body>
</html>
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Razor Example - Displaying Images
Suppose you have 3 images in your image folder, and you want to display images dynamically by the users choice.
This is easily done by a little Razor code.
If you have an image called "Photo1.jpg" in your images folder on your web site, you can display the image using an HTML <img> element like this:
<img src="images/Photo1.jpg" alt="Sample" />
The example below shows how to display a selected picture which the user selects from a drop-down list:
Razor Example
@{
var imagePath="";
if (Request["Choice"] != null)
{imagePath="images/" + Request["Choice"];}
}
<!DOCTYPE html>
<html>
<body>
<h1>Display Images</h1>
<form method="post" action="">
I want to see:
<select name="Choice">
<option value="Photo1.jpg">Photo 1</option>
<option value="Photo2.jpg">Photo 2</option>
<option value="Photo3.jpg">Photo 3</option>
</select>
<input type="submit" value="Submit" />
@if (imagePath != "")
{
<p>
<img src="@imagePath" alt="Sample" />
</p>
}
</form>
</body>
</html>
Run example »
Example explained
The server creates a variable called imagePath.
The HTML page has a drop-down list (a <select> element) named Choice. It lets the user select a friendly name (like Photo 1), and passes a file name (like Photo1.jpg) when the page is submitted to the web server.
The Razor code reads the value of Choice by Request["Choice"]. If it has a value the code constructs a path to the image (images/Photo1.jpg, and stores it in the variable imagePath.
In the HTML page there is an <img> element to display the image. The src attribute is set to the value of the imagePath variable when the page displays.
The <img> element is in an if block to prevent trying to display an image with no name (like the first time the page is displayed.
