Complex Tags

A complex tag is usually composed of one or more basic tags.

Layout tag

Layout Tag, syntax: ${ layout("path") } The layout tag is similar to an ASP.NET master page. It must appear on the first line of the page.

Example — parent page (parent.html):

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>JNTemplate demo</title>
  </head>
  <body>
      ${body}
  </body>
</html>

Example — child page (index.html):

$layout("parent.html")
<p>i'm child!</p>

Output:

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>JNTemplate demo</title>
  </head>
  <body>
      <p>i'm child!</p>
  </body>
</html>

WARNING

Supported since version 1.4+. The layout tag must be declared on the top line of the template.

IF tag

IF Tag, syntax:

$if(condition1)
..
$elseif(condition2)
..
$else
..
$end

Used for logic control. It must end with the End tag. Multiple conditions can be handled with the Elseif tag (also written elif). The condition can be a logical expression tag or a single object; when it is a single object it is evaluated by the following rules:

1. Number: 0 is false, otherwise true
2. String: null or "" is false, otherwise true
3. Object: null is false, otherwise true

Example

var  templateContent = @"
${if(value>5)}
    value is greater than 5
${elif(value<5)}
    value is less than 5
${else}
    value equals 5
${end}
";
var template = Engine.CreateTemplate(templateContent);
template.Set("value", 10);
var result = template.Render();
Assert.AreEqual("value is greater than 5", result);

Elseif tag

Elseif Tag, syntax: ${ elseif("condition") }

The Elseif tag is a child tag of the IF tag: it can only be used together with IF and cannot stand alone. From v1.4.0 it can also be shortened to $elif(condition). See the IF tag for usage.

Else tag

Else Tag, syntax: ${ else }

The Else tag is a child tag of the IF tag: it can only be used together with IF and cannot stand alone. See the IF tag for usage.

Iteration tag

Foreach Tag, syntax:

$foreach(childObject in collection)
...
$end

The collection must implement the IEnumerable interface. Usage is similar to foreach in C#.

Note: objects created inside the loop body (that is, between foreach and end) cannot be accessed after the tag ends, and values set with the SET tag inside the tag body become invalid once execution leaves the tag scope.

From 1.4 on, foreach . in . can be shortened to for . in .

Example

var  templateContent = @"
<ul>
$foreach(i in list)
<li>$i</li>
${end}
</ul>
";
var template = Engine.CreateTemplate(templateContent);
template.Set("list", new char[] { 'j', 'n', 't', 'e', 'm', 'p', 'l', 'a', 't', 'e' });
var result = template.Render();

Output:

<ul>
<li>j</li>
<li>n</li>
<li>t</li>
<li>e</li>
<li>m</li>
<li>p</li>
<li>l</li>
<li>a</li>
<li>t</li>
<li>e</li>
</ul>

TIP

The object must implement IEnumerable. Pay attention to the scope.

For tag

For Tag, syntax:

$for(initialization; condition; increment)
...
$end

The for tag must end with end. Note: objects created inside the loop body (that is, between for and end) cannot be accessed after the tag ends. If the condition is always true, the tag causes an infinite loop, so use it carefully, e.g. $for(i=0;i<1;i--)

Example:

var  templateContent = @"
<ul>
$for(i=1;i<4;i++)
<li>$i</li>
${end}
</ul>
";
var template = Engine.CreateTemplate(templateContent);
var result = template.Render();

Output:

<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>

TIP

Make sure the condition will not cause an infinite loop.

Set tag

Set Tag, syntax: $set(name=value)

The set tag defines a variable or changes the value of the specified variable, e.g. $(set id=10) or $(set model=GetData())

Example:

var templateContent = "$set(id=10)$id";
var template = Engine.CreateTemplate(templateContent);
var result = template.Render();
Assert.AreEqual("10", result);

WARNING

1. When used inside for and foreach, pay attention to the scope.

2. Only variables can be assigned; properties and fields cannot.

Load tag

Load Tag, syntax: $load(path)

The load tag loads the specified template page and parses its content.

Example — template file header.html:

<p>Hello, $name</p>

Back-end code

var templateContent = "$load(\"header.html\")";
var template = Engine.CreateTemplate(templateContent);
template.Set("name","jntemplate");
var result = template.Render();

Output:

<p>Hello, jntemplate</p>

Include tag

Include Tag, syntax: $include(path)

The include tag includes another template page. It works like the LoadTag, but the content is not parsed.

Example — template file header.html:

<p>Hello, $name</p>

Back-end code

var templateContent = "$include(\"include.html\")";
var template = Engine.CreateTemplate(templateContent);
template.Set("name","jntemplate");
var result = template.Render();

Output:

<p>Hello, $name</p>