Find as you type in C#

Question

Im trying to emulate a 'find as you type' function like that of the address bar ("awesome bar") in FireFox. I want a suggestion box to appear below a textbox, and the suggestion box contains strings that contain what is in the textbox. I looked at the autocomplete feature of a normal WinForms textbox, but it seems to only search the beginning of the strings.

Has anyone here built or have experience with implementing something like this?

edit: Some clarification- It is a WinForms project. It needs to search inside a string, not just the beginning (which is what a normal textbox does if i recall correctly). And the suggestions should be displayed in a popup like a textbox autocomplete.

Answer 1

You need to handle the TextChanged event for your text entry field, and when the text changes, start a new thread running that will apply the new search. If the text changes before you get your results back, just kill the thread. If the thread returns results in time, display them.

You can get slightly more advanced (e.g. wait for a short time after the text changes so that the user can type a word without you triggering off loads of useless threads) but essentially that's it.

Answer 2

There was a discussion earlier on this topic where the author concluded that you are better off doing the whole thing yourself.

How can I dynamically change auto complete entries in a C# combobox or textbox?

Answer 3

I did something vaguely similar, but more like the iTunes® search box than the Awesomebar. My control used the textbox to actively filter a grid; so it wasn't for autocompletion.

...but... basically I had a DataView of all eligible items, whenever the TextBox's Text changed I'd update the Filter to hide all non-matching items. It worked well and might suit your needs for filtering the data--but not sure how to go about using it as an AutoComplete source for the textbox.

Answer 4

I have done such a thing for an app of mine not too much time ago.

What I did is make my search function in a new thread, so every time I typed a new letter, it called the search function in another thread, so I could keep on typing.

I can post some code if you need, but this should be enough to get you started. :)

Answer 5

Hemmed and hawed about deleting this after I noticed the OP edit mentioned winforms, but I think it'll be useful to anyone who comes here looking for the same but for asp.net apps.

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Just because nobody has mentioned it yet, for a webforms app you absolutely want to do this with ajax (.net controls or pure JS, your choice). The feature is often called "autocomplete" and the one thing you don't want it to be breaking the seamlessness by making server round trips at the page level.

I suggest you look at this and this.

Answer 6

I've used Search As You Type in C# and How do I make a Textbox Postback on KeyUp?

Basically you use the keyup action to call a postback thats attached to the trigger to the update panel. then you do your update in the textbox_changed event with the dataview or whatever your backend looks like.