Home > Xtext > Xtext Content Assist Auto Activation

Xtext Content Assist Auto Activation

Xtext offers nice Content Assist facilities. JDT offers a nice additional feature: Content assist is autoactivated if a certain character (.) is typed. To activate this feature in Xtext simply customize your UiModule

public class MyDslUiModule extends org.xtext.example.mydsl.ui.AbstractMyDslUiModule {
public MyDslUiModule(AbstractUIPlugin plugin) {
	public void configure(Binder binder) {

In this case content assist is autoactivated on . , and :

  1. September 20, 2011 at 08:47

    Very nice!

  2. Axel Terfloth
    September 22, 2011 at 21:27

    good to know…

  3. November 23, 2011 at 20:58

    Is it also possible to use NEWLINE or TAB for auto activation? Or is another approach required?

    • November 23, 2011 at 21:26

      .toInstance(” \t”);

      works for me

  4. December 12, 2011 at 20:36

    Thank you! The tab auto activation works indeed, a newline with \n did not work on windows. The solution was \r\n like:

    String eol = System.getProperty(“line.separator”);
    .toInstance(” \t” + eol);

    • Michal
      April 25, 2012 at 08:12

      Thank you for this nice how-to… Made usage nicer!
      I am getting only little imperfection, if I use previous example with “eol”: It provides content assist in the end of line and also on the beginning of new line :(. I would need assist only on newline. Any suggestion to this?

      • April 25, 2012 at 08:19

        no i do not know the backend of the code in that detail. Guess you have to debug yourself

  5. Brad
    May 10, 2012 at 21:48

    Is it possible to activate the content assist mechanism after entering certain grammar keywords too?

  6. Hans Peterson
    May 27, 2012 at 17:03

    I hava a basici question to this Xtext Content Assist Auto Activation:

    Do I need to create this class MyDslUiModule under the src or src-gen folder?

    • May 27, 2012 at 20:27


      not create! edit – it is already there. btw it is never a good idea to create any custom class or to edit any class in the src-gen folder since it will be erased when you run the workflow

  7. Latha
    July 12, 2012 at 04:57

    Could we customize this auto activation to work only in selected scenarios? For example, I do not want the auto content assist in case of comments. Is there a way to achieve this?

    • July 18, 2012 at 06:22

      Sorry I don’t know that. Guess you have to look at the code yourself

  8. Ed Willink
    August 3, 2013 at 10:46

    It might be worth adding the Fragment configuration as well

    bindFactory.addConfiguredBinding(String.class.getName(), “binder.bind(String.class).annotatedWith(com.google.inject.name.Names.named((org.eclipse.xtext.ui.editor.contentassist.XtextContentAssistProcessor.COMPLETION_AUTO_ACTIVATION_CHARS))).toInstance(\”.,:\”);”);

  9. Puneet Patwari
    November 21, 2014 at 13:03


    I tried the above approach but it is not working at all. I have to still press ctrl+space. đŸ˜¦
    Please help.

    • November 24, 2014 at 11:17

      can you give more details on what you are exactly? the best place to do so would be in the tmf xtext part of eclipse forum or at Stackoverflow

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