Conditional Logic and Loops in MVC

Conditional Logic and Loops

ASP.NET server code lets you perform tasks based on conditions and write code that repeats statementsa specific number of times (loops).

Testing Conditions

To test a simple condition you use the if statement, which returns true or false based on a test youspecify:


 @{var showToday = true;if(showToday){@DateTime.Today;}}

        @{
            showToday = false;
            if(showToday)
            {
                @DateTime.Today;
            }
            else
            {
                <br />
                <text>Sorry!</text>
            }}

9/13/2012 12:00:00 AM
Sorry!

If else Code

You can add multiple conditions using an else if block:


@{
            var theBalance = 4.99;
           if(theBalance == 0)
           {  
                      <p>You have a zero balance.</p>          
           }
            else if (theBalance > 0 && theBalance <= 5)
            {
            <p>Your balance of $@theBalance is very low.</p>
            }
            else
            {
            <p>Your balance is: $@theBalance</p>
            }
            }

Your balance of $4.99 is very low.

Switch case Code

To test a large number of conditions, use a switch block:


 @{
                var weekday = "Wednesday";
                var greeting = "";
                switch (weekday)
                {
                    case "Monday":
                        greeting = "Ok, it's a marvelous Monday";
                        break;
                    case "Tuesday":
                        greeting = "It's a tremendous Tuesday";
                        break;
                    case "Wednesday":
                        greeting = "Wild Wednesday is here!";
                        break;
                    default:
                        greeting = "It's some other day, oh well.";
                        break;
                }
                <p>Since it is @weekday, the message for today is: @greeting</p>
                }

Since it is Wednesday, the message for today is: Wild Wednesday is here!

For Looping Code

 @for(var i = 10; i < 21; i++){<p style="font-size: @(i + "pt")">My font size is now: @i</p>}

My font size is now: 10

My font size is now: 11

My font size is now: 12

My font size is now: 13

My font size is now: 14

My font size is now: 15

My font size is now: 16

My font size is now: 17

My font size is now: 18

My font size is now: 19

My font size is now: 20

For each Looping Code

<ul>@foreach (var myItem in Request.ServerVariables){<li>@myItem</li>}</ul>

• ALL_HTTP
• ALL_RAW
• APPL_MD_PATH
• APPL_PHYSICAL_PATH
• AUTH_TYPE
• AUTH_USER
• AUTH_PASSWORD
• LOGON_USER
• REMOTE_USER
• CERT_COOKIE
• CERT_FLAGS
• CERT_ISSUER
• CERT_KEYSIZE
• CERT_SECRETKEYSIZE
• CERT_SERIALNUMBER
• CERT_SERVER_ISSUER
• CERT_SERVER_SUBJECT
• CERT_SUBJECT
• CONTENT_LENGTH
• CONTENT_TYPE
• GATEWAY_INTERFACE
• HTTPS
• HTTPS_KEYSIZE
• HTTPS_SECRETKEYSIZE
• HTTPS_SERVER_ISSUER
• HTTPS_SERVER_SUBJECT
• INSTANCE_ID
• INSTANCE_META_PATH
• LOCAL_ADDR
• PATH_INFO
• PATH_TRANSLATED
• QUERY_STRING
• REMOTE_ADDR
• REMOTE_HOST
• REMOTE_PORT
• REQUEST_METHOD
• SCRIPT_NAME
• SERVER_NAME
• SERVER_PORT
• SERVER_PORT_SECURE
• SERVER_PROTOCOL
• SERVER_SOFTWARE
• URL
• HTTP_CONNECTION
• HTTP_ACCEPT
• HTTP_ACCEPT_ENCODING
• HTTP_ACCEPT_LANGUAGE
• HTTP_COOKIE
• HTTP_HOST
• HTTP_REFERER
• HTTP_USER_AGENT
• HTTP_DNT

While Looping Code

@{var countNum = 0;while (countNum < 50){countNum += 1;<p>Line #@countNum: </p>}}

Line #1:
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