How To Create Autocomplete on an Text Field in Dynamics CRM

Scenario:

It might be requested you: when user types texts to a textbox, System helps to user with suggesting some values from couple entities in Dynamics CRM or maybe fetching records from any other resources.

Solution;

It is very simple, just register your code to the key press event for the object and fill the object with suggested values .

There is supported event for MSCRM engine (it has been so long since i do not call MSCRM :) ) calls : addOnKeyPress - when user presses a key over the object, the event is called for given delegated method

please consider performance and load on the network so;

1- do not fetch data from external resources each time user clicks the key - you can wait for the first 3 or 4 letters from the user
2- never fetch all matching records what user types so far, add "top 20 records" to your fetch method 

Implementation:

first of all register the method while loading the form in Dynamics CRM:

<Practice> 
 Create a javascript (.js) for each entity in Dynamics CRM for dedicated client scripting as much as   possible.
</Practice>

<Practice>
method standards could be

form_onLoad(executionContext) {

    var formContext = executionContext.getFormContext(); //to get the formContext

}

form_onSave(executionContext) {

    var formContext = executionContext.getFormContext(); //to get the formContext

}
</Practice>

now let's delegate our method to the event

function form_onLoad(executionContext) {

    var formContext = executionContext.getFormContext(); //to get the formContext

    formContext.getControl("<name of the textbox>").addOnKeyPress(<name of the textbox>_addOnKeyPress);
}


We should create a custom method : <name of the textbox>_addOnKeyPress which takes Execution Context parameter

function <name of the textbox>_addOnKeyPress(executionContext) {

    var formContext = executionContext.getFormContext(); //to get the formContext
    var input = formContext.getControl("<name of the textbox>").getValue();

    var resultSet = null;

    if (input != null && input.length > 3) {
        try {
                    // activate AutoComplete (or AutoFill)
                    resultSet = fetchDataMethodfromOtherSources(param1,param2,....);           
            }
        } catch (exp) {
            alert(exp);
        }
    }

    if (resultSet != null && resultSet.results != null && resultSet.results.length > 0) {
        executionContext.getEventSource().showAutoComplete(resultSet);
    } else {
        executionContext.getEventSource().hideAutoComplete();
    }
}


enjoy...