Develop Reference

Prevent printing spaces in C# TextBox

I want to make a TextBox that doesn't allow entering spaces. I disabled typing spaces with the keyboard:
void textBox_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Space)
{
e.Handled = true;
}
}
But if the user copies a string with spaces like "Hello world", he can paste it into the TextBox and there will be spaces in it.

you can add a TextChanged Event Handler for your TextBox and add below code in that TextChanged event:
TextBox1.Text = TextBox1.Text.Replace(" ", "");

A better control approach
private void textBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.V && e.Modifiers == Keys.Control) {
removeSpaces();
}
//Handle Ctrl+Ins
if (e.KeyCode == Keys.Control && e.KeyCode == Keys.Insert)
{
removeSpaces();
}
}
private void removeSpaces()
{
textBox.Text = textBox.Text.Replace(" ", string.Empty);
}
// To control Mouse Right click
private void textBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
textBox1.ContextMenu = new ContextMenu();
}
}
SIMPLE Solution for all
private void textBox1_TextChanged(object sender, EventArgs e)
{
textBox1.Text = textBox1.Text.Replace(" ", string.Empty);
}

A simple way is removing white space after entering data. Like:
txt_Box.Text = txt_Box.Text.Replace(" ","");

break button_click event when enter pressed

Is an easy way to cancel click event when user hit enter on button (instead of mouse click on button?)
i have tried with:
private void button3_Click(object sender, EventArgs e)
{
KeyEventArgs ke = e as KeyEventArgs;
if (ke != null)
{
if (ke.KeyCode == Keys.Enter)
{
return;
}
}
}
But ke is null

public void btnClick(object sender, EventArgs e)
{
bool IsMouse = (e is System.Windows.Forms.MouseEventArgs);
// If not mouse, they hit spacebar or enter
}

Yes it will be null. because EventArgs is not KeyEventArgs
KeyEventArgs will be passed as a parameter to KeyDown or KeyUp events. You're messing up things.

You can do something like this
private bool flag = false;
private void button1_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Return)
{
flag = true;
}
}
private void button1_Click(object sender, EventArgs e)
{
if (flag)
{
flag = false;
return;
}
//else do original task
}

You can handle KeyPress event for the button and disable or ignore enter key there instead of returning in button click

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
if ((keyData & Keys.KeyCode) == Keys.Enter)
{
SendKeys.Send("{Tab}");
return true;
}
return false;
}

Textbox on which Keys Delete and backspace Works

I need to have a text box on which events of Delete and Backspace works.Is it possible to have such a text box in C#,or restrict the behavior of text box in such a way. Other keys do not work.

Use TextBox.KeyPress event:
private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == Keys.Delete || e.KeyCode == Keys.Back)
{
// your stuff
}
e.Handled = true;
}

For winforms you can do it like this:
protected void myTextBox_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
e.Handled = !IsValidCharacter(e.KeyChar);
}
private bool IsValidCharacter(Keys c)
{
bool isValid = false;
if (c == Keys.Space)
{
isValid = true;
}
return isValid;
}

If you want delete key works ..
private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
Keys k = e.KeyCode
If Not (k = Keys.Back Or k = Keys.Delete)
{
e.Handled = True
}
}

Make code for multiple textbox when press Enter send command Tab better

i already have code when user press key Enter on keyboard, it return tab and "jump" to next field, its working great, its possible make it for 2 or 3 textbox, problem when need make it on multiple textbox like 20 textbox for each form, its just not work.
See code:
// Detect if Enter key is pressed on each text box, mute sound enter "ding" sound and replace Enter for tab (problem that have make it for each textbox)
private void txtAltura_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Enter)
{
e.Handled = true; //Silenciar Enter
SendKeys.Send("{TAB}");
}
}
private void txtLargura_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Enter)
{
e.Handled = true; //Silenciar Enter
SendKeys.Send("{TAB}");
}
}
private void txtProfundidade_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Enter)
{
e.Handled = true; //Silenciar Enter
SendKeys.Send("{TAB}");
}
}
//execute keypress command when enter is typed on textbox
private void txtProfundidade_TextChanged(object sender, EventArgs e)
{
if (txtProfundidade.Text != "") { foreach (char c in txtProfundidade.Text.ToCharArray()) txtProfundidade_KeyPress(sender, new KeyPressEventArgs(c)); }
}
private void txtLargura_TextChanged(object sender, EventArgs e)
{
if (txtLargura.Text != "") { foreach (char c in txtLargura.Text.ToCharArray()) txtLargura_KeyPress(sender, new KeyPressEventArgs(c)); }
}
private void txtAltura_TextChanged(object sender, EventArgs e)
{
if (txtAltura.Text != ""){foreach (char c in txtAltura.Text.ToCharArray()) txtAltura_KeyPress(sender, new KeyPressEventArgs(c));}
}
Hope make it better.
Thanks in advance..

if its windows form app can use this, this will replace tab key press with Enter key
protected override bool ProcessKeyPreview(ref Message m)
{
if (m.Msg == 0x0100 && (int)m.WParam == 13)
{
this.ProcessTabKey(true);
}
return base.ProcessKeyPreview(ref m);
}

From what I understand, you're trying to figure out a way to assign event handlers to multiple textbox controls and don't want to write a handler for each one. If that's the case, try this:
private void Form1_Load(object sender, EventArgs e)
{
foreach (TextBox textBox in this.Controls.OfType<TextBox>())
{
textBox.KeyDown += new KeyEventHandler(textBox_KeyDown);
}
}
void textBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
e.Handled = true;
SendKeys.Send("{TAB}");
}
}
This will assign a handler to each textbox control on the form.

That worked perfectly well.
I also have to repeat this on each textbox to check if all codes was filled and update statusbar:
private void txtAltura_TextChanged(object sender, EventArgs e)
{
testePreenchidoecalculo();
}
private void txtLargura_TextChanged(object sender, EventArgs e)
{
testePreenchidoecalculo();
}
private void txtProfundidade_TextChanged(object sender, EventArgs e)
{
testePreenchidoecalculo();
}
Its possible to make it better ?

How do I capture the enter key in a windows forms combobox

How do I capture the enter key in a windows forms combo box when the combobox is active?
I've tried to listen to KeyDown and KeyPress and I've created a subclass and overridden ProcessDialogKey, but nothing seems to work.
Any ideas?
/P

Hook up the KeyPress event to a method like this:
protected void myCombo_OnKeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == 13)
{
MessageBox.Show("Enter pressed", "Attention");
}
}
I've tested this in a WinForms application with VS2008 and it works.
If it isn't working for you, please post your code.

In case you define AcceptButton on your form, you cannot listen to Enter key in KeyDown/KeyUp/KeyPress.
In order to check for that, you need to override ProcessCmdKey on FORM:
protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
if ((this.ActiveControl == myComboBox) && (keyData == Keys.Return)) {
MessageBox.Show("Combo Enter");
return true;
} else {
return base.ProcessCmdKey(ref msg, keyData);
}
}
In this example that would give you message box if you are on combo box and it works as before for all other controls.

or altertatively you can hook up the KeyDown event:
private void comboBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
MessageBox.Show("Enter pressed.");
}
}

private void comboBox1_KeyDown( object sender, EventArgs e )
{
if( e.KeyCode == Keys.Enter )
{
// Do something here...
} else Application.DoEvents();
}

Try this:
protected override bool ProcessCmdKey(ref Message msg, Keys k)
{
if (k == Keys.Enter || k == Keys.Return)
{
this.Text = null;
return true;
}
return base.ProcessCmdKey(ref msg, k);
}

It could be that your dialog has a button that's eating the enter key because it's set to be the AcceptButton in the form property.
If that's the case then you solve this like this by unsetting the AcceptButton property when the control gets focus then resetting it back once the control loses focus ( in my code, button1 is the accept button )
private void comboBox1_Enter(object sender, EventArgs e)
{
this.AcceptButton = null;
}
private void comboBox1_Leave(object sender, EventArgs e)
{
this.AcceptButton = button1;
}
private void comboBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyData == Keys.Enter)
{
MessageBox.Show("Hello");
}
}
I have to admit not liking my own solution as it seems a little hacky to unset/set the AcceptButton property so if anyone has a better solution then I'd be interested

protected void Form_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == 13) // or Key.Enter or Key.Return
{
MessageBox.Show("Enter pressed", "KeyPress Event");
}
}
Don't forget to set KeyPreview to true on the form.