C# Wait for User to Finish Typing in a Text Box

C# wait for user to finish typing in a Text Box

You can use textbox onChange() event. If text is changed in textbox, check if entered value is a number and calculate total value according to the other value.

How to handle the TextChanged event only when the user stops typing?

Create a System.Windows.Forms.Timer and reset it (e.g. stop then start it) after every keypress. If the timer event is triggered, disable the timer.

How to know when the user is done typing on C# windows form textbox

You can either use the OnLostFocus to tell when the user's focus leaves the textbox.

Otherwise you can use OnKeyPress and a timer to tell how long since the last keystroke.

Don't raise TextChanged while continuous typing

I've come across this problem several times, and based on my own experience I found this solution simple and neat so far. It is based on Windows Form but can be converted to WPF easily.

How it works:

When TypeAssistant learns that a text change has happened, it runs a timer. After WaitingMilliSeconds the timer raises Idle event. By handling this event, you can do whatever job you wish (such as processing the entered tex). If another text change occurs in the time frame starting from the time that the timer starts and WaitingMilliSeconds later, the timer resets.

public class TypeAssistant
{
public event EventHandler Idled = delegate { };
public int WaitingMilliSeconds { get; set; }
System.Threading.Timer waitingTimer;

public TypeAssistant(int waitingMilliSeconds = 600)
{
WaitingMilliSeconds = waitingMilliSeconds;
waitingTimer = new Timer(p =>
{
Idled(this, EventArgs.Empty);
});
}
public void TextChanged()
{
waitingTimer.Change(WaitingMilliSeconds, System.Threading.Timeout.Infinite);
}
}

Usage:

public partial class Form1 : Form
{
TypeAssistant assistant;
public Form1()
{
InitializeComponent();
assistant = new TypeAssistant();
assistant.Idled += assistant_Idled;
}

void assistant_Idled(object sender, EventArgs e)
{
this.Invoke(
new MethodInvoker(() =>
{
// do your job here
}));
}

private void yourFastReactingTextBox_TextChanged(object sender, EventArgs e)
{
assistant.TextChanged();
}
}

Advantages:

  • Simple!
  • Working in WPF and Windows Form
  • Working with .Net Framework 3.5+

Disadvantages:

  • Runs one more thread
  • Needs Invocation instead of direct manipulation of form

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

One approach:

  1. Create a Timer with an Interval of X milliseconds

    The interval should be about 300ms; more than a normal time between keystrokes, and also reasonable time to wait between finishing and the update occurring

  2. In the input's TextChanged event, Stop() and then Start() the Timer

    This will restart the Timer if it is already running, so if the user keeps typing at a normal rate, each change will restart the timer.

  3. In the timer's Tick event, Stop() the Timer and do the long transaction

  4. Optional: Handle the Leave and KeyDown events so that leaving the control or pressing Enter will Stop() the Timer and do the long transaction.

This will cause an update if the text has changed, and the user hasn't made any changes in X milliseconds.

One problem with the "Measure the time since the last update" approach you're considering is that if the last change is made quickly, the update won't happen, and there won't be any subsequent changes to trigger another check.

Note: There must be a one to one pairing between TextBoxes and Timers; if you're planning on doing this with more than one input, I'd consider building a UserControl that wraps this functionality.

Textbox delay events

Instead of using a TextChanged event, use the TextBox _Validating event and the _Validated event. The _Validating event is fired only when the text box loses focus, i.e., when the user clicks on another control, e.g., a Button or another TextBox. When this happens, the _Validating event is fired and you test the value in the text box. If it's invalid, you cancel the _Validating event. If its valid, you DON'T cancel the _Validating event, and as a a result the _Validated event is fired. In the _Validated event, you do what you neeed to do when the input data is valid. Use an errorprovider to inform the user when the input data is invalid.

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();

errorProvider1.SetError(TXBheight, "");

//NEW NEW NEW
buttonCancel.CausesValidation = false;
}

private void Button1_Click(object sender, EventArgs e)
{
// do what is needed when the button is clicked
}

private void TXBheight_Validating(object sender, CancelEventArgs e)
{

errorProvider1.SetError(TXBheight, "");

if (String.IsNullOrEmpty(TXBheight.Text))
{
errorProvider1.SetError(TXBheight, "Height is a required field");
e.Cancel = true;
return;
}

if (int.Parse(TXBheight.Text) < 8)
{
errorProvider1.SetError(TXBheight, "Height must be GE 8");
e.Cancel = true;
return;
}

if (int.Parse(TXBheight.Text) > 32)
{
errorProvider1.SetError(TXBheight, "Height must be LE 32");
e.Cancel = true;
return;
}

}

private void TXBheight_Validated(object sender, EventArgs e)
{
//this event is fired when the data is valid, i.e.,
// if e.Cancel in the _Validating method is NOT set to cancel

}

//NEW NEW NEW
private void ButtonCancel_Click(object sender, EventArgs e)
{
AutoValidate = AutoValidate.Disable;
Close();
}

// NEW #2

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
if (e.CloseReason == CloseReason.UserClosing)
{
DialogResult result = MessageBox.Show("Do you really want to exit?", "Dialog Title", MessageBoxButtons.YesNo);
if (result == DialogResult.Yes)
{
Environment.Exit(0);
}
else
{
e.Cancel = true;
}
}
else
{
e.Cancel = true;
}
}
}

Making TextBox Clear when user starts typing

private bool firsttime = true;

private void TXTBX_HourlyRatae_TextChanged(object sender, EventArgs e)
{
if (firsttime)
{
TXTBX.HourlyRate.Clear();
TXTBX.HoursWorked.Clear();
firsttime = false;
}
}

if you want to do it everytime you enter the textbox handle the loss focus event

private void TXTBX_HourlyRatae_LostFocus(object sender, System.EventArgs e)
{

} firsttime = true;


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