To make sure that the user name input is valid, I added such callback method to do the verification:
Regex UserNameRE = new Regex(#"^[a-zA-Z]\w*$");
//being called when input box is not focused any more
private void UserNameInput_Leave(object sender, EventArgs e)
{
//pop up a warning when user name input is invalid
if (!UserNameRE.IsMatch(UserNameInput.Text))
{
MessageBox.Show("Invalid User Name!");
this.UserNameInput.Text = "";
this.UserNameInput.Focus();
}
}
The method will be called when user finished their inputting(the method is bounded with the event-"leaving the input box"). It works when user left a invalid User_Name and begin to enter a password.
But it also works when user click another tab, e.g. the Register tab. I don't want this happen. Because the user obviously don't wanna login anymore if he clicks "Register" tab, and my C# app shouldnot pop up a warning box and force them inputting a valid user name again.
How can the C# tell the difference of such 2 situations? It should be easy if I know which object is being clicked.
You will have source of event in object sender in UserNameInput_Leave event.
private void UserNameInput_Leave(object sender, EventArgs e)
{
//sender is source of event here
}
Here's an option:
private void UserNameInput_Leave(object sender, EventArgs e)
{
if (sender.GetType() != typeof(TextBox))
{
return;
}
TextBox tBox = (TextBox)sender;
//pop up a warning when user name input is invalid
if (!UserNameRE.IsMatch(UserNameInput.Text) && tBox.Name == UserNameInput.Name)
{
MessageBox.Show("Invalid User Name!");
this.UserNameInput.Text = "";
this.UserNameInput.Focus();
}
}
I am not sure if there's a right solution for this particular scenario here.
When you add a handler to validate your control on mouse leave, definitely it will be executed first regardless you clicked on another control within the tab or another tab itself.
This normal flow can't be ignored easily. It must be possible by hanlding the message loop yourself but the event based flow, first leave focus, and selected index change (selecting) event will be fired. I would suggest you not to disturb the flow as the validation is client side and pretty fast. Instead of messagebox, I would recommend you to use ErrorProvider and attach to the control whenever required. Also messagebox is quite disturbing and as per your code, you're forcefully making it focus to the textbox again.
How about the following code?
public partial class Form1 : Form
{
ErrorProvider errorProvider = new ErrorProvider();
public Form1()
{
InitializeComponent();
textBox1.Validating += new CancelEventHandler(textBox1_Validating);
}
private void textBox1_Leave(object sender, EventArgs e)
{
textBox1.CausesValidation = true;
}
void textBox1_Validating(object sender, CancelEventArgs e)
{
Regex UserNameRE = new Regex(#"^[a-zA-Z]\w*$");
if (!UserNameRE.IsMatch(textBox1.Text))
{
errorProvider.SetError(this.textBox1, "Invalid username");
}
}
}
Related
Hello im making my first project with about 10 different textboxes where the user puts data in. when he/she clicks the the textbox the textbox text clears and a virtual numpad form pops up and when he leaves the textbox the numpad "hides".
right now (or i would) i have 2 events for every textbox, a click event and a leave event,
private void sheetWidthBox_Enter(object sender, EventArgs e)
{
vnumPadForm.Location = PointToScreen(new Point(sheetWidthBox.Right, sheetWidthBox.Top));
vnumPadForm.Show();
}
Im sure there is a way of dynamically coding that in one event and just grabbing the label name. i have played around with it a bit on my numpad like this and it works good;
private void button_Click(object sender, EventArgs e)
{
Button b = (Button)sender;
string num = b.Text;
SendKeys.SendWait(num);
}
Like that but instead i want to get the label name
right now (or i would) i have 2 events for every textbox, a click event and a leave event,
it works but very inefficient.
Change the name of the handler to something generic like "anyBox_Enter()", and update to the code below:
TextBox curTextBox = null;
private void anyBox_Enter(object sender, EventArgs e)
{
curTextBox = sender as TextBox;
vnumPadForm.Location = PointToScreen(new Point(curTextBox.Right, curTextBox.Top));
vnumPadForm.Show();
}
Note that I added a class level variable called "curTextBox" that gets set from the generic handler! This will track whatever TextBox was entered last.
Now, one by one, select each TextBox on your Form that you want to wire up to this common handler. After selecting each one, in the Properties Pane, click on the "Lightning Bolt" Icon to switch to the events for that control if they are not already showing. Find the "Enter" entry and change the dropdown to the right so that it says "anyBox_Enter".
Then in your button click handlers you can use the "curTextBox" variable to know where to send the key:
private void button_Click(object sender, EventArgs e)
{
Button b = (Button)sender;
string num = b.Text;
if (curTextBox != null) {
curTextBox.Text = num; // or possibly APPEND this to the TB?
}
}
Im working with errorprovider in a c# winforms application.
Now I want to have a "double" validation. Once on the textfields directly, so the user sees that he has made some errors, and once on the button itself. So when there are still errors, the "save" button will keep greyed out or "disabled".
Because I don't want to block my user when he is making an error, and I want him to be able to make the changes whenever he wants im using the event "leave" or on focus lost. This because otherwise I noticed you cannot go to another field, until you changed your error.
So, now the code:
private void txtFirstname_Leave(object sender, EventArgs e)
{
if (!InputChecks.IsFilledIn(txtFirstname.Text))
{
errorProvider1.SetError(txtFirstname, "Firstname needs to be filled in!");
isValidated = false;
}
else
{
errorProvider1.SetError(txtFirstname, "");
isValidated = true;
}
}
So far, so good. The error provider works correctly and my user can edit whenever he wants.
public void setSaveButton()
{
if (isValidated == true)
{
btnSave.Enabled = true;
}
else
{
btnSave.Enabled = false;
}
}
bool isValidated;
private void btnSave_Click(object sender, EventArgs e)
{
if (isValidated == true)
{
employeePresenter.addEmployee(txtFirstname.Text, txtLastname.Text, txtUsername.Text, txtPassword.Text);
}
}
This was still okey in my head. BUT, as I give the ability to the user to change the issues whenever they want, this doesn't work. I tried to put the method "setSaveButton()" under "isvalidated" but this is not working either. Because of the focus lost.
Anyone has a better idea for this? I have been looking on google and the only things i found was a single validation with the errorprovider, or the event validating. But these events don't allow users to edit their errors whenever they want. It blocks them into one particular text field.
You don't need to make the save button disabled. It's enough to check ValidateChildren method of your form and if it returned false, it means there is some validation error. To use this approach you should remember to set e.Cancel = true in Validating event of the control when you set an error for control.
Also to let the user to move between controls even if there is an error, set AutoValidate property of your Form to EnableAllowFocusChange in designer or using code:
this.AutoValidate = System.Windows.Forms.AutoValidate.EnableAllowFocusChange;
Code for Validation:
private void txtFirstname_Validating(object sender, CancelEventArgs e)
{
if (string.IsNullOrEmpty(this.txtFirstname.Text))
{
this.errorProvider1.SetError(this.txtFirstname, "Some Error");
e.Cancel = true;
}
else
{
this.errorProvider1.SetError(this.txtFirstname, null);
}
}
private void btnSave_Click(object sender, EventArgs e)
{
if (this.ValidateChildren())
{
//Here the form is in a valid state
//Do what you need when the form is valid
}
else
{
//Show error summary
}
}
I want to activate a textbox when users starts typing in my Windows 8.1 Store app.
I tried handling KeyDown event of Page, something like this code:
private void pageRoot_KeyDown(object sender, KeyRoutedEventArgs e)
{
if (SearchBox.FocusState == Windows.UI.Xaml.FocusState.Unfocused)
{
string pressedKey = e.Key.ToString();
SearchBox.Text = pressedKey;
SearchBox.Focus(Windows.UI.Xaml.FocusState.Keyboard);
}
}
But the problem is e.Key.ToString() always returns capital english character of the pressed key, while user might be typing in another language. For example, the Key D types ی in Persian keyboard, and user might want to type in Persian, but e.Key.ToString() will still return D instead of ی.
Also I tried making that textbox always focused (my page contains some gridviews and so on, and a textbox) and while this solution works on PCs, it makes the on-screen keyboard to always appear on tablets.
So, what should I do? Is there any way to get the exact typed character in KeyDown event?
As Mark Hall suggested, It seemed that CoreWindow.CharacterReceived event can help solving this issue.
So, I found the final answer here.
This is the code from that link:
public Foo()
{
this.InitializeComponent();
Window.Current.CoreWindow.CharacterReceived += KeyPress;
}
void KeyPress(CoreWindow sender, CharacterReceivedEventArgs args)
{
args.Handled = true;
Debug.WriteLine("KeyPress " + Convert.ToChar(args.KeyCode));
return;
}
But this event will fire anywhere independent of current active page. So I must remove that event when user navigates to another page, and add it again when user comes back.
Update: I also had to move the cursor of the textbox to the end of the text, so user can write naturally. Here's my final code:
private void KeyPress(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.CharacterReceivedEventArgs args)
{
if (SearchBox.FocusState == Windows.UI.Xaml.FocusState.Unfocused)
{
SearchBox.Text = Convert.ToChar(args.KeyCode).ToString();
SearchBox.SelectionStart = SearchBox.Text.Length;
SearchBox.SelectionLength = 0;
SearchBox.Focus(FocusState.Programmatic);
}
}
private void pageRoot_GotFocus(object sender, RoutedEventArgs e)
{
Window.Current.CoreWindow.CharacterReceived += KeyPress;
}
private void pageRoot_LostFocus(object sender, RoutedEventArgs e)
{
Window.Current.CoreWindow.CharacterReceived -= KeyPress;
}
I have made a custom Number Keypad control that I want to place in my winform application. All of the buttons have an OnClick event to send a value to the focused textbox in my form where I have placed my custom control. Like this:
private void btnNum1_Click(object sender, EventArgs e)
{
if (focusedCtrl != null && focusedCtrl is TextBox)
{
focusedCtrl.Focus();
SendKeys.Send("1");
}
}
focusedCtrl is supposed to be set on the MouseDown event of the button like this:
private void btnNum1_MouseDown(object sender, EventArgs e)
{
focusedCtrl = this.ActiveControl;
}
where this.ActiveControl represents the active control on the form.
My problem is that the button always receives the focus before the event detects what the focused control was previously. How can I detect which control had the focus before the button got the focus? Is there another event I should be using? Thanks in advance!
EDIT: Also, I would rather not use the GotFocus event on each textbox in the form to set focusedCtrl since that can be tedious and because I would like to have all the coding of my custom control be in the control itself and not on the form where it is placed. (I will do this, though, if there is no other practical way to do what I am asking)
Your requirement is fairly unwise, you'll want some kind of guarantee that your button isn't going to poke text into inappropriate places. You really do need to have the form co-operate, only it knows what places are appropriate.
But it is not impossible, you can sniff at input events before they are dispatched to the control with the focus. In other words, record which control has the focus before the focusing event is fired. That's possible in Winforms with the IMessageFilter interface.
Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox onto your form, replacing your existing buttons.
using System;
using System.Windows.Forms;
class CalculatorButton : Button, IMessageFilter {
public string Digit { get; set; }
protected override void OnClick(EventArgs e) {
var box = lastFocused as TextBoxBase;
if (box != null) {
box.AppendText(this.Digit);
box.SelectionStart = box.Text.Length;
box.Focus();
}
base.OnClick(e);
}
protected override void OnHandleCreated(EventArgs e) {
if (!this.DesignMode) Application.AddMessageFilter(this);
base.OnHandleCreated(e);
}
protected override void OnHandleDestroyed(EventArgs e) {
Application.RemoveMessageFilter(this);
base.OnHandleDestroyed(e);
}
bool IMessageFilter.PreFilterMessage(ref Message m) {
var focused = this.FindForm().ActiveControl;
if (focused != null && focused.GetType() != this.GetType()) lastFocused = focused;
return false;
}
private Control lastFocused;
}
Control focusedCtrl;
//Enter event handler for all your TextBoxes
private void TextBoxesEnter(object sender, EventArgs e){
focusedCtrl = sender as TextBox;
}
//Click event handler for your btnNum1
private void btnNum1_Click(object sender, EventArgs e)
{
if (focusedCtrl != null){
focusedCtrl.Focus();
SendKeys.Send("1");
}
}
you have an event called lostFocus you can use
button1.LostFocus +=new EventHandler(dataGridView1_LostFocus);
and in the event:
Control lastFocused;
void dataGridView1_LostFocus(object sender, EventArgs e)
{
lastFocused = sender as Control;
}
in that way you can always know what is the Control that was focused previously
now, correct me if i'm wrong, but you do it for the SendKeys.Send("1"); to know which textBox need to receive the number. for that you can use GotFocus event and register only the textBoxs to it.
you can also do what windows is doing and use just one textbox like here:
if it's fits your needs
What about using this with the parameter forward = false?
Control.SelectNextControl Method
You'd probably call it on your "custom Number Keypad control".
I am using a windows form and within the form i have a user control with two labels, one that has a message ENTER AMOUNT and the other where I am putting the values typed by the user (like when you go to an ATM) it starts showing the number .. it works fine if i dont have any other controls on the user control.. but the moment i add a button it does not work, it wont start showing the numbers as I use my numeric key pad.. but if i remove whatever button i added it works again... Here is my user control code.
public partial class OperationAmount : UserControl
{
public OperationAmount()
{
InitializeComponent();
}
private int _inputNumber = 0;
private void OperationAmount_Load(object sender, EventArgs e)
{
}
private void Form_KeyAmountPressed(object sender, KeyPressEventArgs e)
{
if (!Char.IsNumber(e.KeyChar))
{
return;
}
else if (lblOperationAmount.Text.Length > 9)
{
return;
}
else
{
_inputNumber = 10 * _inputNumber + Int32.Parse(e.KeyChar.ToString());
ReformatOutput();
}
}
private void ReformatOutput()
{
lblOperationAmount.Text = String.Format("{0:0.00}", (double)_inputNumber / 100.0);
}
}
Probably the new control steals the keypresses from your Form_KeyAmountPressed method because now it has the focus and receive the event KeyPress.
A simple workaround would be to add the method Form_KeyAmountPressed also at the KeyPress event of the button. Try also to set the TabStop property of the button to false. (not sure if this has any effect when the button is the only control that can get focus on your user control).