How can I add list custom settings into an existing picklist data type in visualforce?

Question

I created a list custom settings, and I need to add this into an existing picklist in my visualforce page.

I know how to display this list custom setting as a drop down in visualforce page, but I don't know how can I add this list into the existing picklist. When users select the picklist, and they can see this list custom settings as one of the picklist option.

Answer 1

My example based on the following settings:

• Custom object: MyObject__c
• A normal picklist: Picklist__c
• Custom setting object: MySettingsList__c
• Custom setting fields: Setting1 and Setting2

First i will read all values of the custom picklist and add it to the select option list. Then read the custom settings and add it to the list too.

Controller:

public String selectedValue { get; set; }

public List<SelectOption> getMyOptions(){ 
    List<SelectOption> options = new List<SelectOption>();      

    // Reading picklist values and labels
    Schema.DescribeFieldResult fieldResult = MyObject__c.Picklist__c.getDescribe();
    List<Schema.PicklistEntry> picklistEntries = fieldResult.getPicklistValues();

    // Adding apicklist values to the select list
    for(Schema.PicklistEntry entry : picklistEntries){
        options.add(new SelectOption(entry.getValue(), entry.getLabel())); 
    }

    // Now adding custom settings to the select list
    for(MySettingsList__c setting : MySettingsList__c.getAll().values()){
        options.add(new SelectOption(setting.name, setting.Setting1__c)); 
        options.add(new SelectOption(setting.name, setting.Setting2__c)); 
    }     

    return options;
}

Visualforce page:

<apex:selectList value="{!selectedValue}" size="1" multiselect="false">
    <apex:selectOptions value="{!MyOptions}"/>
</apex:selectList>

Then it should look like this: