All templates defined using <apex:composition> must have one or more child <apex:insert> tags. An <apex:insert> tag indicates to pages that import the template that a section needs a definition. Any Visualforce page that imports a template using <apex:composition> must use <apex:define> to specify the content of each <apex:insert> section of the template.
You can create a skeleton template that allows subsequent Visualforce pages to implement different content within the same standard structure. To do so, create a template page with the <apex:composition> tag.
The following example shows how you can use <apex:composition>, <apex:insert>, and <apex:define> to implement a skeleton template.
<apex:page controller="compositionExample"> </apex:page>
public class compositionExample{ String name; Integer age; String meal; String color; Boolean showGreeting = false; public PageReference save() { showGreeting = true; return null; } public void setNameField(String nameField) { name = nameField; } public String getNameField() { return name; } public void setAgeField(Integer ageField) { age= ageField; } public Integer getAgeField() { return age; } public void setMealField(String mealField) { meal= mealField; } public String getMealField() { return meal; } public void setColorField(String colorField) { color = colorField; } public String getColorField() { return color; } public Boolean getShowGreeting() { return showGreeting; } }
<apex:page controller="compositionExample"> <apex:form > <apex:outputLabel value="Enter your name: " for="nameField"/> <apex:inputText id="nameField" value="{!nameField}"/> <br /> <apex:insert name="age" /> <br /> <apex:insert name="meal" /> <br /> <p>That's everything, right?</p> <apex:commandButton action="{!save}" value="Save" id="saveButton"/> </apex:form> </apex:page>
<apex:page controller="compositionExample"> <apex:messages/> <apex:composition template="myFormComposition"> <apex:define name="meal"> <apex:outputLabel value="Enter your favorite meal: " for="mealField"/> <apex:inputText id="mealField" value="{!mealField}"/> </apex:define> <apex:define name="age"> <apex:outputLabel value="Enter your age: " for="ageField"/> <apex:inputText id="ageField" value="{!ageField}"/> </apex:define> <apex:outputLabel value="Enter your favorite color: " for="colorField"/> <apex:inputText id="colorField" value="{!colorField}"/> </apex:composition> <apex:outputText id="greeting" rendered="{!showGreeting}" value="Hello {!nameField}. You look {!ageField} years old. Would you like some {!colorField} {!mealField}?"/> </apex:page>
<apex:page controller="compositionExample"> <apex:messages/> <apex:composition template="myFormComposition"> <apex:define name="meal"> <apex:outputLabel value="Enter your favorite meal: " for="mealField"/> <apex:inputText id="mealField" value="{!mealField}"/> </apex:define> <apex:define name="age"> <p>You look great for your age!</p> </apex:define> </apex:composition> <apex:outputText id="greeting" rendered="{!showGreeting}" value="Hello {!nameField}. Would you like some delicious {!mealField}?"/> </apex:page>
A dynamic template allows you to assign a template through a PageReference. The template name is assigned to a controller method that returns a PageReference containing the template you want to use.
<apex:page> <apex:insert name="name" /> </apex:page>
public class dynamicComposition { public PageReference getmyTemplate() { return Page.myAppliedTemplate; } }
<apex:page controller="dynamicComposition"> <apex:composition template="{!myTemplate}"> <apex:define name="name"> Hello {!$User.FirstName}, you look quite well. </apex:define> </apex:composition> </apex:page>