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Why is my C# WinForms window not closing in response to Enter key?

I have a basic WinForms project where the user clicks a button. This opens another form as follows:
form2 myForm2 = new form2();
myForm2.ShowDialog();
Inside this new form, there are four buttons which represent values. The user presses the SPACE key to jump between buttons and the ENTER key to select one. When the user presses ENTER on a button I want the form to close. For this is I use 'this.Close()'. This works for absolutely fine with every key other than ENTER. I am using visual studio so I have inserted a break point and stepped over the code. The ENTER key is detected successully and I can step over the code 'this.Close()' but the window never closes. My code is a followed:
private void button1_KeyDown(object sender, PreviewKeyDownEventArgs e)
{
if (e.KeyCode == Keys.Space)
{
// Change colour of the button you are on. This works fine.
}
else if (e.KeyCode == Keys.Enter)
{
this.Close();
// This will close the form with all keys other than the Enter key. Yet the enter key is
// successfully detected and the program enters this else if statement.
}
}
Any help is much appreciated, Thanks.

I'd override ProcessCmdKey() and make the space key act like the tab key to select the next control. Then just handle each the click event of each button like normal. The click handler for the buttons will fire when the user presses enter:
public partial class form2 : Form
{
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
Button btn = this.ActiveControl as Button;
if (btn != null)
{
if (keyData == Keys.Space)
{
// possibly do something else with "btn"?...
this.SelectNextControl(btn, true, true, true, true);
return true; // suppress default handling of space
}
}
return base.ProcessCmdKey(ref msg, keyData);
}
private void button1_Click(object sender, EventArgs e)
{
// possibly set some value?
Console.WriteLine("button1");
this.DialogResult = DialogResult.OK;
}
private void button2_Click(object sender, EventArgs e)
{
// possibly set some value?
Console.WriteLine("button2");
this.DialogResult = DialogResult.OK;
}
private void button3_Click(object sender, EventArgs e)
{
// possibly set some value?
Console.WriteLine("button3");
this.DialogResult = DialogResult.OK;
}
private void button4_Click(object sender, EventArgs e)
{
// possibly set some value?
Console.WriteLine("button4");
this.DialogResult = DialogResult.OK;
}
}
An alternative approach would be to also trap the enter key in ProcessCmdKey() like this:
public partial class Form2 : Form
{
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
Button btn = this.ActiveControl as Button;
if (btn != null)
{
if (keyData == Keys.Space)
{
Console.WriteLine("Space -> Tab");
// possibly do something else with "btn"?...
this.SelectNextControl(btn, true, true, true, true);
return true; // suppress default handling of space
}
else if (keyData == Keys.Enter)
{
Console.WriteLine("Enter in ProcessCmdKey() for " + btn.Name);
// possibly do something else with "btn"?...
this.Close();
// < or >
this.DialogResult = DialogResult.OK;
return true;
}
}
return base.ProcessCmdKey(ref msg, keyData);
}
}

Looking into signature of the handler (object sender, PreviewKeyDownEventArgs e) apparently OP is already handling PreviewKeyDown event.
I reproduced and solved the problem.
The behavior is different when you open a Form using Show or ShowDialog. Everything works as expected with Show, but when using ShowDialog, to close the form in PreviewKeyDown, you need to use one of the following options:
private void button1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
e.IsInputKey = true;
this.Close();
// OR
// if (e.KeyData == Keys.Enter)
// this.BeginInvoke(new Action(() => this.Close()));
// OR first hide, then close, without calling BeginInvoke
// this.Hide();
// this.Close();
}
There should be something about model message loop. I didn't traced in details, but you may find the following links useful:
LocalModalMessageLoop in Application
CheckCloseDialog in Form
WMClose in Form
Just as a side note: If the Enter should be handled at form level, then setting AcceptButton of the form or overriding ProcessKeyDown or ProcessDialogKey of the form is the way to go.

When number of char in textbox is reached, jump to button to Enter

I have a textbox in a Windows Form. (C#)
In that textbox the user can enter 9 char.
After entering the char, the user hase to go to a button and click.
Is there a possibility, when the 9 char are reached, there is a automatic selection of the button, so that the user has only to tap Enter en the next step of the program can start ?
Excuses for my English. :-)

try this
if (txtBox.Text.Length == 9)
{
btnEnter.Focus();
}
this will focus on the btnEnter if character is equal to 9, you might add additional validation to block user input if it will be more than 9 or change the logic to txtBox.Text.Length >= 9

An alternative to Gabriel's solution would be to hook the KeyUp event, check if the return key has been pressed, and initiate a button click:
private void button1_Click(object sender, EventArgs e)
{
// do whatever
}
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Return && textBox1.Text.Length == 6) // check if key is return and textbox length is 6
{
button1.PerformClick(); // perform a button click
}
}

Another approach is to set the AcceptButton property of the FORM to your Button. This causes it to be pressed when the Enter key is pressed, even when it is not focused. Then you set its initial state to disabled, and only enable it when there are 9 chars in your TextBox. So the user will enter the value and simply hit Enter, the Button will not need to have focus:
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
button1.Enabled = false;
this.AcceptButton = button1;
textBox1.MaxLength = 9;
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
button1.Enabled = (textBox1.TextLength == 9);
}
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("7...8...9");
}
}

I called my void TextBox_Changed.
I linked it in the textbox Properties to TextChanged.
Thanks for the quick answers.

How do I make it so pressing Enter in a textbox does the same as clicking the button next to it?

I'm working on a C# based chat client in Windows Forms. I want to make it so a user won't always have to click the button when they want to send a message. Instead, hitting the Enter or Return key should be sufficient.
Here is a screnshot of my Form:

Handle KeyPress event for your textbox and code it like below in .cs page
private void textbox1_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == 13)
{
MessageBox.Show("Your code here for enter key", "Enter Pressed");
}
}

You could create a Keydownevent for the textbox and ask for the enter key:
private void TextBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
button1.PerformClick();
e.Handled = true;
e.SuppressKeyPress = true;
}
}

You can use the KeyPress event of the TextBox to know which key is pressed. When the Return key is pressed, programmatically click the Senden button.
Event Handler:
private void CheckEnter(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
if (e.KeyChar == (char)13)
{
// Enter key pressed
}
}
And register the event like this (or use the visual editor):
this.textBox1.KeyPress += new System.Windows.Forms.KeyPressEventHandler(CheckEnter);
Source

You can use your textbox keydown event to check whether you have pressed enter or not then call the submit button click event from there,
private void textBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
buttonsSubmit_Click(this, new EventArgs());
}
}

Child form closed on enter click

I have two Forms Frm1 and Frm2.
Both having single textbox.
On keyup event of first form textbox, second form is opened if KeyChar is ENTER.
Now on KeyUp event for textbox in 2nd form I am closing this form i.e submitting.
Now both events are called. Is there any way to get rid of thi?
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
Frm2 frm=new Frm2();
Frm2.RefToForm1=this;
frm.StartPosition = FormStartPosition.CenterParent;
frm.ShowDialog(this);
}
}
Now in second form
private void textBox2_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
this.RefToForm1.textBox1.Text=textBox2.Text;
this.Close()
}
}
Problem is when I press enter on textBox1 , form2 is opened and closed immediately.
Any Solutions

you can set the windows form property for-
1- AcceptButton - button id ( on which button you have to submit.)
2-CancelButton - button id ( on which button you have to close the form.)

There's no reason that releasing the Enter key when textBox1 is focused and no instance of Frm2 is opened yet, would also raise the KeyUp event on textBox2 in Frm2.
Are you sure you don't have some addition code in your project that's causing this behavior? Did you try putting a breakpoint on this.Close() in textBox2_GotFocus method to see if it actually gets executed in your scenario?
I even created a small sample project using your code with some minor modifications to make it work (explained in comments):
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
Frm2 frm=new Frm2();
frm.RefToForm1=this; // you said RefToForm1 isn't static and it shouldn't be
frm.StartPosition = FormStartPosition.CenterParent;
frm.ShowDialog(this);
}
}
private void textBox2_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
this.RefToForm1.textBox1.Text=textBox2.Text;
this.Close(); // missing semicolon
}
}
public Form1 RefToForm1 { get; set; } // property in Frm2
You can download this working sample project from here.

define a boolean variable in form 2, set it to false initially and close the form based on that variable. You could set it to true later when you need it. You could use the GotFocus method of the textbox to set to it true. e.g
textBox2.GotFocus += textBox2_GotFocus;
Set the boolean to true inside the textBox2_GotFocus method. Your key_up method would look like this :
private void textBox2_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
if(boolean_var){
this.RefToForm1.textBox1.Text=textBox2.Text;
this.Close();
}
}
}

Perhaps you could prevent the second form from closing if the textbox is empty -- assuming something needs to go in there for it to close.
Could you give us more information about what you're trying to do with this? Perhaps there's another way to solve the feature you're trying to create.

Not able to capture Enter key in WinForms text box

When the user is entering a number into a text box, I would like them to be able to press Enter and simulate pressing an Update button elsewhere on the form. I have looked this up several places online, and this seems to be the code I want, but it's not working. When data has been put in the text box and Enter is pressed, all I get is a ding. What am I doing wrong? (Visual Studio 2008)
private void tbxMod_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
btnMod.PerformClick();
}
}

Are you sure the click on the button isn't performed ? I just did a test, it works fine for me. And here's the way to prevent the "ding" sound :
private void tbxMod_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
btnMod.PerformClick();
e.SuppressKeyPress = true;
}
}

A few thoughts:
does the form have an accept-button (set on the Form) that might be stealing ret
does the textbox have validation enabled and it failing? try turning that off
does something have key-preview enabled?

Under "Properties" of the Form. Category (Misc) has the following options:
AcceptButton, CancelButton, KeyPreview, & ToolTip.
Setting the AcceptButton to the button you want to have clicked when you press the Enter key should do the trick.

Set e.Handled to true immediately after the line btnMod.PerformClick();.
Hope this helps.

I had to combine Thomas' answer and Marc's. I did have an AcceptButton set on the form so I had to do all of this:
private void tbxMod_Enter(object sender, EventArgs e)
{
AcceptButton = null;
}
private void tbxMod_Leave(object sender, EventArgs e)
{
AcceptButton = buttonOK;
}
private void tbxMod_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
// Click your button here or whatever
e.Handled = true;
}
}
I used t0mm13b's e.Handled, though Thomas' e.SuppressKeyPress seems to work as well. I'm not sure what the difference might be.

form properties > set KeyPreview to true

The simple code below works just fine (hitting the Enter key while in textBoxPlatypusNumber displays "UpdatePlatypusGrid() entered"); the form's KeyPreview is set to false:
private void textBoxPlatypusNumber_KeyDown(object sender, KeyEventArgs e) {
if (e.KeyCode == Keys.Enter)
{
UpdatePlatypusGrid();
}
}
private void UpdatePlatypusGrid()
{
MessageBox.Show("UpdatePlatypusGrid() entered");
}