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Set the Caret/Cursor position in C# WPF when textbox clicked on

I am using a textbox for a login window. I want the textbox to display "Username" in light grey so the user knows to use that box to type in the username. Whenever the user clicks on the textbox even if it's in the middle of the word username I want the cursor to go to the first position and username will disappear when they start typing. I tried using the PreviewMouseDown event but it only works inside breakpoints but doesn't trigger at all outside it. Using the PreviewMouseUp event it works, but other caret positions can be selected before the cursor jumps to the beginning. I want it to appear like the user is unable to select any cursor position besides the first. This is the code I've tried.
private bool textboxuserfirstchange = true;
private void eventTextChanged(object sender, TextChangedEventArgs e)
{
if (textBoxUser.Text != "Username")
{
if (textboxuserfirstchange)
{
textBoxUser.Text = textBoxUser.Text[0].ToString();
textBoxUser.SelectionStart = 1;
textBoxUser.Opacity = 100;
}
textboxuserfirstchange = false;
}
}
private void eventPreviewMouseDown(object sender, MouseButtonEventArgs e)
{
if (textboxuserfirstchange)
{
textBoxUser.Focus();
textBoxUser.Select(0, 0); //None of these working
textBoxUser.SelectionStart = 0;
textBoxUser.CaretIndex = 0;
}
}

You could for example handle the GotKeyboardFocus and PreviewTextInput event. Something like this:
private const string Watermark = "Username";
private void TextBox_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
if (textBoxUser.Text == Watermark)
textBoxUser.Dispatcher.BeginInvoke(new Action(() => textBoxUser.CaretIndex = 0), DispatcherPriority.Background);
}
private void textBoxUser_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
if (textBoxUser.Text == Watermark)
textBoxUser.Text = string.Empty;
}

Make TextBox Editable by ContextMenuStrip - c# winform

I have a textbox in my C# Winform. The program assigns a value to the textbox by default.
I want the user to have a right click function to edit this text at runtime. So when the user right click to edit, the backgroud should become white and user should be able to edit the text. And after editing, the background should return to default and non editable
I have created a ContextMenuStrip with right click event to edit text as follows and assigned readonly property to false when user right clicks and press edit menu item:
private void editTextToolStripMenuItem_Click(object sender, EventArgs e)
{
itxt_CommonTitle.ReadOnly = false;
}
I am not sure how to proceed further. Is this possible using textbox?

If you have not changed the BackColor of the TextBox in the designer then the background color should automatically change from white to gray when you set ReadOnly = true and change from gray back to white when you set ReadOnly = false. However, if you have changed it to something else in the designer, then the easiest way is just to set a private variable to remember the original BackColor before you enable the control for editing. Then you can restore the color after you set it back to read-only.
private void editToolStripMenuItem_Click(object sender, EventArgs e)
{
MakeTextBoxEditable(itxt_CommonTitle);
}
private void itxt_CommonTitle_Leave(object sender, EventArgs e)
{
MakeTextBoxReadOnly(itxt_CommonTitle);
}
private void Form1_Click(object sender, EventArgs e)
{
MakeTextBoxReadOnly(itxt_CommonTitle);
}
private Color origTextBoxBackColor = SystemColors.Control;
private void MakeTextBoxEditable(TextBox textBox)
{
origTextBoxBackColor = textBox.BackColor;
textBox.ReadOnly = false;
textBox.BackColor = Color.White;
textBox.Focus();
}
private void MakeTextBoxReadOnly(TextBox textBox)
{
textBox.ReadOnly = true;
textBox.BackColor = origTextBoxBackColor;
}

I think you are missing a process. After edit, there should be an update or save method.
textbox readonly = true;
edit textbox: textbox readonly = false;
button save: textbox readonyl = true;
Edit:
Something like this:
private void buttonSave_Click(object sender, EventArgs e)
{
textBox1.ReadOnly = true;
}
private void editToolStripMenuItem_Click(object sender, EventArgs e)
{
textBox1.ReadOnly = false;
}
You dont need to change backColor, just readonly prop is fine.

How to design a keypad in C#?

I am new to C# and I am planing to design my own keypad but I don't know how/where to start. as shown in photo, I have 4 textBoxes the keypad buttons.
The first problem came into my mind was: how can I detect the cursor location (which textBox is the cursor in?).
So for example if I had only one textbox then it is easy I could write inside button1 : textBox1.text = "1" and inside button2 : textBox1.text = "2" and inside button_A : textBox1.text = "A".... and so on but I have 4 textBoxes and it is confusing.
Can you please provide me with an idea or what to write inside each button to print its value in the textbox which the cursor is in.
Thank you professionals.

Firstly, have a textbox that represents the one that is selected (outside of subroutines but inside the class):
TextBox SelectedTextBox = null;
And then make the "Click" event of each TextBox look like this:
private void textBoxNUM_Click(object sender, EventArgs e)
{
SelectedTextBox = sender as TextBox;
}
And then make the "Click" event of each Button look like this:
private void buttonNUM_Click(object sender, EventArgs e)
{
if (SelectedTextBox != null)
{
SelectedTextBox.Text = buttonNUM.Text;//Or set it to the actual value, whatever.
}
}
Or if that one doesn't work, this should.
private void buttonNUM_Click(object sender, EventArgs e)
{
if (SelectedTextBox != null)
{
(SelectedTextBox as TextBox).Text = buttonNUM.Text;//Or set it to the actual value, whatever.
}
}

To check if a textbox is focused you can do
if(textbox1.Focused)
{
//Print the value of the button to textbox 1
}
else if (textbox2.Focused)
{
//Print the value to textbox 2
}
UPDATE:
Since the textbox will lose focus when you click the button, you should have a temporary textbox (ie lastTextboxThatWasFocused) which is saved to everytime a textbox gains focus. Write an OnFocused Method and do something like
public void Textbox1OnFocused(/*Sender Event Args*/)
{
lastTextboxThatWasFocused=textbox1;
}
Then on button click you can do
if(lastTextboxThatWasFocused.Equals(textbox1))
{
//ETC.
}

You can give something along these lines a try. Create a generic click handler for the buttons and then assign the value to a textbox the text from the button, which happens to be the value. You can check which box was the last one focused in the TextBoxes' Click event. Create a global variable to store which one and use it in the below method.
private TextBox SelectedTextBox { get; set; }
private void NumericButton_Click(object sender, EventArgs e)
{
var clickedBox = sender as Button;
if (clickedBox != null)
{
this.SelectedTextBox.Text += clickedBox.Text;
}
}
private void TextBox_Click(object sender, EventArgs e)
{
var thisBox = sender as TextBox;
if (thisBox == null)
{
return;
}
this.SelectedTextBox = thisBox;
}

Try this code:
TextBox LastTxtBox;
private void textBox_Enter(object sender, EventArgs e)
{
LastTxtBox = sender as TextBox;
}
private void button_Click(object sender, EventArgs e)
{
LastTxtBox.Text = this.ActiveControl.Text;
}
Add textBox_Enter function to all textboxes enter event.
Add button_Click to all buttons click event.

Button Enter Event
Control _activeControl;
private void NumberPadButton_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
if (_activeControl is TextBox || _activeControl is RichTextBox)
{
_activeControl.Text += btn.Text;
if (!_activeControl.Focused) _activeControl.Focus();
}
}
TextBox or RihTextBox Enter Event
private void TextBoxEnter_Click(object sender, EventArgs e)
{
_activeControl = (Control)sender;
}

Show button only when focus is on textbox

Is this possible to display button on Windows Form only when focus is on specific textbox?
Tried that with this approach:
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("OK");
}
private void textBox2_Enter(object sender, EventArgs e)
{
button3.Visible = true;
}
private void textBox2_Leave(object sender, EventArgs e)
{
button3.Visible = false;
}
No luck, because button click does not work then, because button is hidden immediately after textbox lost focus, preventing it from firing button3_Click(/*...*/) { /*...*/ } event.
Now I'm doing it like that:
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("OK");
}
private void textBox2_Enter(object sender, EventArgs e)
{
button3.Visible = true;
}
private void textBox2_Leave(object sender, EventArgs e)
{
//button3.Visible = false;
DoAfter(() => button3.Visible = false);
}
private async void DoAfter(Action action, int seconds = 1)
{
await Task.Delay(seconds*1000);
action();
}
Form now waits for a second and only then hides button3.
Is there any better approach?

I think you want to display the button only when focus is on specific textbox or the focus is on the button.
To do this you can check the Focused property of button3 in the Leave event of textBox2 and only hide the button if the button doesn't have focus. Note that the button will get focus before the Leave event of textBox2 fires.
You will then need to hide the button in the scenario where button3 loses focus and the focus moves to somewhere other than textBox2. You can use exactly the same technique here by handling the Leave event of button3 and only hiding button3 if textBox2 does not have focus.
The following code should fit your requirements:
private void textBox2_Leave(object sender, EventArgs e)
{
if (!button3.Focused)
{
button3.Visible = false;
}
}
private void button3_Leave(object sender, EventArgs e)
{
if (!textBox2.Focused)
{
button3.Visible = false;
}
}
private void textBox2_Enter(object sender, EventArgs e)
{
button3.Visible = true;
}
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("Button clicked");
}

Why not work with the GotFocus and LostFocus event of the TextBox?
private void textBox2_GotFocus(object sender, EventArgs e)
{
button3.Visible = true;
}
Then hide the button on the click event.
private void button3_Click(object sender, EventArgs e)
{
MessageBox.Show("OK");
button3.Visible = false;
}

How about you add a Panel and place the button and text boxes in that panel and when user MouseHovers that Panel then display the button...
This way user would be able to click on the button...
This is the event you are looking for, I think...
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.mousehover(v=vs.110).aspx
UPDATE:
var textboxFocussed = false;
private void textBox2_Enter(object sender, EventArgs e)
{
textboxFocussed = true;
}
private void textBox2_Leave(object sender, EventArgs e)
{
textboxFocussed = false;
}
UPDATE 2
private void Panel_GotFocus(object sender, EventArgs e)
{
button3.Visible = textboxFocussed;
}
private void Panel_LostFocus(object sender, EventArgs e)
{
button3.Visible = false;
}
Here are the details of the Panel Events

you can add Enter event handler for all controls on form at Load. Just make sure to skip the controls on which you want to show the button.
List<string> strControlException = new List<string>();
public Form1()
{
InitializeComponent();
strControlException.Add("btnMain");
strControlException.Add("txtMain");
}
private void Form1_Load(object sender, EventArgs e)
{
for (int i = 0; i < this.Controls.Count;i++ )
{
if (!strControlException.Contains(Controls[i].Name))
{
Controls[i].Enter += new EventHandler(hideButton);
}
}
}
private void txtMain_Enter(object sender, EventArgs e)
{
btnMain.Visible = true;
}
private void hideButton(object sender, EventArgs e)
{
btnMain.Visible = false;
}
btnMain (Button you want to Manipulate) and txtMain (Which controls the vibility of the button) are the controls in contention here
Add more controls on the form to test.
Explanation for the above code :
First initialize a list with the names of controls that should show the Button
On Form Load add an Event handler to all controls (except the one in our list)
In the handler function hide the button. (You might want to perform more logic here based on the control that called this function)
Button is hidden by default and only on textbox Enter event we show the button.

CheckBox button and ContextMenuStrip for dropdown menu

I'm tring to implement a button which have a dropdown menu when checked and this menu is gone when unchecked. My problem is I cannot uncheck the checkbox when it or its menu lost focus.
The checkbox's appearance mode is button.
My code:
private void cbSettings_CheckedChanged(object sender, EventArgs e)
{
if (cbSettings.Checked) {cmsSettings.Show(cbSettings, 0, cbSettings.Height);}
else {cmsSettings.Hide();}
}
I've tried to uncheck the checkBox on contextMenuStrip's VisibleChanged / Closed event but this caused menu not to hide (or hide and show immediately).

The example below does not, of course, include the code you would need for swapping BackGroundImage of the CheckBox to indicate CheckState. The events to "wire-up" should be obvious. Hope this is helpful.
// tested in VS 2010 Pro, .NET 4.0 FrameWork Client Profile
// uses:
// CheckBox named 'checkBox1
// ContextMenuStrip named 'contextMenuStrip1
// TextBox named 'cMenuSelectionInfo for run-time checking of results
// used to position the ContextMenuStrip
private Point cPoint;
// context click ? dubious assumption that 'right' = context click
private bool cmOpenedRight;
// the clicked ToolStripMenuItem
private ToolStripMenuItem tsMIClicked;
private void checkBox1_MouseDown(object sender, MouseEventArgs e)
{
cmOpenedRight = e.Button == MouseButtons.Right;
}
private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
// positioning the CheckBox like this
// is something in a 'real-world' example
// you'd want to do in the Form.Load event !
// unless, of course, you'd made the CheckBox movable
if(checkBox1.Checked)
{
contextMenuStrip1.Show();
cPoint = PointToScreen(new Point(checkBox1.Left, checkBox1.Top + checkBox1.Height));
contextMenuStrip1.Location = cPoint;
}
else
{
contextMenuStrip1.Hide();
}
}
private void contextMenuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
{
// assume you do not have to check for null here ?
tsMIClicked = e.ClickedItem as ToolStripMenuItem;
tbCbMenuSelectionInfo.Text = tsMIClicked + " : " + ! (tsMIClicked.Checked);
}
private void contextMenuStrip1_Closing(object sender, ToolStripDropDownClosingEventArgs e)
{
e.Cancel = checkBox1.Checked;
}
private void contextMenuStrip1_Closed(object sender, ToolStripDropDownClosedEventArgs e)
{
if (cmOpenedRight)
{
tbCbMenuSelectionInfo.Text += " : closed because : " + e.CloseReason.ToString();
}
}

I think your approach of unchecking the check box on the context menu's closed event is a good one, what you need is a bit of "event cancelling logic"(c), like this:
private void OnContextClosing(object sender, EventArgs e)
{
_cancel = true;
cbSettings.Checked = false;
_cancel = false;
}
private void cbSettings_CheckedChanged(object sender, EventArgs e)
{
if(_cancel)
return;
if (cbSettings.Checked) {cmsSettings.Show(cbSettings, 0, cbSettings.Height);}
else {cmsSettings.Hide();}
}
This will keep your CheckChanged event from re-checking your checkbox.