asp.net "auto complete" - populate with a special character

First of all, i'm using asp.net c#.

So i searched in many websites but i didnt find any solutions yet.

I use autocompleteextender from asp.net ajax extension. I want to populate specific data list in a textbox when i type开发者_运维知识库d a special character. For example; "When i type a specific character like "@" in a textbox, it should populate me from the db a specific data list".

Until the textbox has a character like "@" it should populated me some list. But i dont wanna populate it on the first word. After i have typed the character "@", it should populate me the list.

Is this possible with ajax auto complete extender? How? If not, How?

Thank you

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As the AjaxControlToolkit is an open source project, you can download project sources and make all customization that you need. In this particular case enough to add very few changes: edit the AutoCompleteBehavior.pre.js file in AutoComplete folder of MicrosoftAjax.Extended project. You need following changes: in the _onTimerTick method change from

if (text.trim().length < this._minimumPrefixLength) {
            this._currentPrefix = null;
            this._update('', null, /* cacheResults */false);
            return;
        }

To

if (text.trim().length < this._minimumPrefixLength || text.indexOf('@') == -1) {