.NET --- Textbox control - wait till user is done typing

Greetings all,

Is there a built in way to know when a user is done typing into a textbox? (Before hitting tab, Or moving the mouse) I have a database query that occurs on the textchanged event and everything works perfectly. However, I noticed that there is a bit of lag of course because if a user is quickly typing into the textbox the program is busy doing a query for each character. So what I was hoping for was a way to see if the user has finished typing. So if they type "a" and stop then an event fires. However, if they type "all the way" the event fires after the y keyup.

I have some ideas floating around my head but I'm sure they aren't the most efficient. Like measuring the time since the last textchange event and if it was > than a certain value then it would proceed to run the rest of my procedures.

let me know what you think.

Language: VB.NET Framework: .Net 2.0

--Edited to clarify "done typing"

.net vb.net textbox

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1 Answer

For those who need something like this in .NET 2.0, here I made a Control that derives from TextBox and uses the same approach.. Hope this help

public partial class TextBox : System.Windows.Forms.TextBox
{

    private ManualResetEvent _delayMSE;
    public event EventHandler OnUserStopTyping;
    private delegate bool TestTimeout();

    public TextBox()
    {
        _delayMSE = new ManualResetEvent(false);
        this.TextChanged += new EventHandler(TextBox_TextChanged);
    }

    void TextBox_TextChanged(object sender, EventArgs e)
    {


        _delayMSE.Set();
        Thread.Sleep(20);
        _delayMSE.Reset();

        TestTimeout tester = new TestTimeout(TBDelay);
        tester.BeginInvoke(new AsyncCallback(Test), tester);

    }


    private void Test(IAsyncResult pResult)
    { 
        bool timedOut = (bool)((TestTimeout)pResult.AsyncState).EndInvoke(pResult);
        if (timedOut)
        {
            if (OnUserStopTyping != null)
                OnUserStopTyping(this, null);
        }
    }

    private bool TBDelay()
    { 
        return !_delayMSE.WaitOne(500, false); 
    }

}

answered 2010-05-05T22:51:27.627

.NET --- Textbox control - wait till user is done typing

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