Having TextChanged Event Fire Immediately as Text is Typed into TextBox

TextChanged does fire as soon as the text is changed.

(If you have a binding on Text that is not the same thing, it is completely independent from the event.)

@Anron answer is correct but i think it works only when we are doing Data binding (using MVVM).

From @thecorp question what i have understood is he is trying to it in code behind file.

You can take advantage of "KeyDown" and "KeyUp" events of textbox or if you are using data binding Aaron anwer should resolve your issue.

You can bind the Text property and make use of the UpdateSourceTrigger.

UpdateSourceTrigger=PropertyChanged

By setting it to PropertyChanged, you will get a notification each and every time the text changes.