I am developing a custom component that has one SelectList and one Command button.

The selectlist is in multi-select mode so an array of string is prepared to capture user selection.

When the button is clicked, an output label will show the values.

Here is the code:

<apex:component controller="zTestComponent" >

<apex:outputPanel id="thepanel">

<apex:selectList value="{!items}" multiselect="true">
<apex:selectOptions value="{!options}"> </apex:selectOptions>
</apex:selectList>
<apex:commandButton value="submit" action="{!submitMethod}" rerender="thepanel"/>
<apex:outputLabel value="{!message}"></apex:outputLabel>

</apex:outputPanel>

</apex:component>

public class zTestComponent {

public List<SelectOption> options
{
get
{
List<SelectOption> op = new List<SelectOption>();
op.add(new SelectOption('1','test 1'));
op.add(new SelectOption('2','test 2'));
return op;
}
}

public List<string> items
{
get;
set;
}

public string message { get; set; }

public PageReference submitMethod() {
message = '';


if (items != null)
for(string item : items)
{
message += item + ',';
}

return null;
}
}