Text added instead of being set in .NET TextBox - c#

This is my LostFocus event handler:
private void txtThrow_LostFocus(object sender, System.EventArgs e)
{
TextBox source = (TextBox)sender;
if (source.Text == "")
source.Text = "0";
}
This actually interferes with txtThrow_KeyPress, so that after I do my processing on my TextBox which accepts to only hold one character, I find it having two: mine and this zero you see here!! What I want to do is to keep txtThrow_KeyPress exactly as it is, but whenever the user types nothing, I want to enforce a zero.
What I can understand from here is that txtThrow_LostFocus is triggered before txtThrow_KeyPress is done with its job, since at the time txtThrow_LostFocus is triggered, the text is still empty. How can that be correct?!

I would recommend using the TextChanged event instead of the KeyPress event. I am assuming the text box could be empty already, and the user presses Backspace or something of the nature.
TextChanged event is triggered every time the text is changed within the field.
And the code you have should work perfectly fine when you fill the new event handler method with such. However, you may need to use
private void txtThrow_LostFocus_TextChanged(object sender, System.EventArgs e)
{
TextBox source = (TextBox)sender;
if (source.Text == "" || source.Text == null)
source.Text = "0"
}
Hope this helps!

Try to this code
private void txtThrow_LostFocus_TextChanged(object sender, System.EventArgs e)
{
TextBox source = (TextBox)sender;
if (string.nullorempty(source.text)
source.Text = "0"
}

Related

Why I can not change focus?

Im making a calculator.and for the buttons that type numbers, I wrote a condition that if the focus was on text box 1, it would enter the text there, if not, it would enter text box 2. But unfortunately the code does not work and I dont understand the problem.
(WindosForm(.Net framework))
if (textBox1.Focus() == true)
{
textBox1.Text = textBox1.Text + "1";
}
else
{
textBox2.Text = textBox2.Text + "1";
}
Subscribe to "Enter" event for your two textbox and save it. Use the same method for the two textboxes.
TextBox focusedTB;
private void textBox_Enter(object sender, EventArgs e)
{
focusedTB = sender as TextBox;
}
...
this.textBox1.Enter += new System.EventHandler(this.textBox_Enter);
...
this.textBox2.Enter += new System.EventHandler(this.textBox_Enter);
Now you know the last textbox that got focus.
private void button1_Click(object sender, EventArgs e)
{
focusedTB.Text += "1";
}
Your code appears to be attempting to check if the control is focused. The correct way to do that is:
if (textBox1.Focused)
{
// Because 'Focused' is a property. 'Focus()' is a method.
textBox1.Text = textBox1.Text + "1";
}
.
.
.
The answer to your question Why I can not change focus? is that textBox1 receives the focus every time you call this:
if (textBox1.Focus())
As mentioned in one of the comments, here's how the Focus method works:
// Summary:
// Sets input focus to the control.
//
// Returns:
// true if the input focus request was successful; otherwise, false.
[EditorBrowsable(EditorBrowsableState.Advanced)]
public bool Focus();
Note: This is a copy-paste of metadata that you can look at by right-clicking over Focus() in your code and selecting Go to Definition then expanding the definition.
I think you talk about Windows Form ?
You cannot manage like this but use event "Enter" of your textboxes, when you click inside the textbox, you give the focus to this textbox and you can do anything inside. Here I put the right focuses TextBox in a variable.
private TextBox _textBoxFocused; //this is always the righ TextBox
private void textBox1_Enter(object sender, EventArgs e)
{
_textBoxFocused = textBox1;
}
private void textBox2_Enter(object sender, EventArgs e)
{
_textBoxFocused = textBox2;
}

Selection of all of the content of TextBox is not working as expected in WPF

Im having troubles with Selecting All content inside of a TextBox.
Ussually by pressing enter I'm jumping from one textbox to another, because there are like 6-7 TextBoxes below each other
in my Grid, and by pressing enter I need to jump from one to another,
private void Grid_PreviewKeyDown_1(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
UIElement element = e.Source as UIElement;
element.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
//TextBox tb = (sender as TextBox);
//if (tb != null)
//{
// tb.SelectAll();
//}
}
}
And while I'm on some of them when I press Enter I'm doing some calculation like this:
private void txt2_PreviewKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Return)
{
try
{
CalculateSomethingFromOtherTextBoxes();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
My Question is next: When I jump from each other and when I finish calculation (enter is pressed), the next TextBox I will jump to I would like SELECTALL of TextBox's content when I jumped on it.
In case I want to edit some value or whatever, and it is confusing sometimes content insidee is selected and sometimes it is not.
I tried setting GotFocus event on each of TextBoxes and It looks like this:
private void txt3_GotFocus(object sender, RoutedEventArgs e)
{
txt3.SelectAll();
}
But unfortunately somehow this is sometimes working sometimes it is not, I mean all of content is selected sometimes and sometimes it is not..
Thanks guys
Cheers
Try to handle the GotKeyboardFocus event instead of the GotFocus event. This should work:
private void txt3_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
txt3.SelectAll();
}
There is no property that you can set to select all of the Text in a TextBlock or TextBox. Selecting all text must be accomplished using the TextBoxBase.SelectAll Method. What you could do in a Style is to set an event handler for the GotFocus event, where the handler code would call SelectAll, but your handler would of course need to be in code and not XAML.
One other possibility would be for you to create an Attached Property that would select the text whenever the TextBox gets focus, but again it's not possible to do this in XAML.

How get Event "item Selected" with AutoComplete in C#?

I have code using an AutoCompleteStringCollection:
private void txtS_TextChanged(object sender, EventArgs e)
{
TextBox t = sender as TextBox;
string[] arr = this.dbService.GetAll();
if (t != null)
{
if (t.Text.Length >= 3)
{
AutoCompleteStringCollection collection = new AutoCompleteStringCollection();
collection.AddRange(arr);
this.txtSerial.AutoCompleteCustomSource = collection;
}
}
}
How can I get the event for "item selected" after user selects an AutoComplete suggestion? And value of field?
There's no such thing as chosen item Event for a textBox, which I believe you're using for the AutoComplete. What you could do is add a key down event to your textBox. There you could verify if the enter key was pressed (clicking on a suggested link is the same as pressing enter). Something like that:
private void textBox1_KeyDown(object sender, KeyEventArgs e) {
if (e.KeyData == Keys.Enter) {
String selItem = this.textBox1.Text;
}
}
Rather than focusing on detecting if an item from the autocomplete list was selected, instead you should check if the current value of the textbox is in the set of autocomplete entries.
if (txtSerial.AutoCompleteCustomSource.Contains(t.Text))
{
// Logic to handle an exact match being selected
...
}
else
{
// Update the autocomplete entries based on what was typed in
}
If the user typed in an exact string which happens to be be within the list of autocomplete values -- OR -- they select that value from the autocomplete list -- should this produce any different behavior? I think that in most cases it should not.
Short answer: make a custom event
Long answer:
You can intercept the KeyDown event of your textbox for numpad Enter or normal Enter and the mouse doubleclick event of the toolbox and compare the content of the toolbox then fire an event if they match that a delegate will pick up.
It depends a bit on the situation and workflow of your program but I have an example where I trigger the check on focuslost of the combobox. And then I check if the selected value is part of the collection:
private void cmbt1Name1_LostFocus(object sender, RoutedEventArgs e)
{
ComboBox cmb = sender as ComboBox;
FillFivePoints(cmb);
}
private void FillFivePoints(ComboBox usedCombobox)
{
if (txtSerial.AutoCompleteCustomSource.Contains(t.Text))
{
...

How to get the NEW text in TextChanged?

In a TextBox I'm monitoring the text changes. I need to check the text before doing some stuff. But I can only check the old text in the moment. How can I get the new Text ?
private void textChanged(object sender, EventArgs e)
{
// need to check the new text
}
I know .NET Framework 4.5 has the new TextChangedEventArgs class but I have to use .NET Framework 2.0.
Getting the NEW value
You can just use the Text property of the TextBox. If this event is used for multiple text boxes then you will want to use the sender parameter to get the correct TextBox control, like so...
private void textChanged(object sender, EventArgs e)
{
TextBox textBox = sender as TextBox;
if(textBox != null)
{
string theText = textBox.Text;
}
}
Getting the OLD value
For those looking to get the old value, you will need to keep track of that yourself. I would suggest a simple variable that starts out as empty, and changes at the end of each event:
string oldValue = "";
private void textChanged(object sender, EventArgs e)
{
TextBox textBox = sender as TextBox;
if(textBox != null)
{
string theText = textBox.Text;
// Do something with OLD value here.
// Finally, update the old value ready for next time.
oldValue = theText;
}
}
You could create your own TextBox control that inherits from the built-in one, and adds this additional functionality, if you plan to use this a lot.
Have a look at the textbox events such as KeyUp, KeyPress etc. For example:
private void textbox_KeyUp(object sender, KeyEventArgs e)
{
// Do whatever you need.
}
Maybe these can help you achieve what you're looking for.
Even with the older .net fw 2.0 you should still have the new and old value in the eventArgs if not in the textbox.text property itself since the event is fired after and not during the text changing.
If you want to do stuff while the text is being changed then try the KeyUp event rather then the Changed.
private void stIDTextBox_TextChanged(object sender, EventArgs e)
{
if (stIDTextBox.TextLength == 6)
{
studentId = stIDTextBox.Text; // Here studentId is a variable.
// this process is used to read textbox value automatically.
// In this case I can read textbox until the char or digit equal to 6.
}
}

How to validate array of text boxes

I am using c# winform.
I have 2dimensional array of text boxes I want them to accept only Letters from A-I I've created the method but that works for only one text box.
Here is my code:
textbox[i,j].Validated+=new EventHandler(TextBox_KeyPress);
private void TextBox_KeyPress(object sender, EventArgs e)
{
bool bTest = txtRegExStringIsValid(textbox[1,1].Text.ToString());
ToolTip tip = new ToolTip();
if (bTest == false)
{
tip.Show("Only A-I", textbox[1,1], 2000);
textbox[1,1].Text = " ";
}
}
private bool txtRegExStringIsValid(string textToValidate)
{
Regex TheRegExpression;
string TheTextToValidate;
string TheRegExTest = #"^[A-I ]+$";
TheTextToValidate = textToValidate;
TheRegExpression = new Regex(TheRegExTest);
if (TheRegExpression.IsMatch(TheTextToValidate))
{
return true;
}
else
{
return false;
}
}
Can anyone please guide what should I do make this code work for all text boxes?
if this works for textbox[1,1] you could register your private void TextBox_KeyPress(object sender, EventArgs e) as eventhandler for all your textboxes and instead of textbox[1,1] you could use ((TextBox)sender)
i want text boxes to accept only letters from a-i actually i am trying to make sudoku
There's a much simpler solution than regular expressions, and you don't even need to handle the Validated event to implement it.
In a situation like this, where there are only certain characters that you want to prevent the user from entering, handling the KeyDown event is a much better solution. The user gets immediate feedback that the letter they tried to enter was not accepted. The alternative (the Validating and Validated events) actually wait until the user tries to leave the textbox to rudely alert them that their input was invalid. Especially for a game, this tends to break concentration and isn't particularly user-friendly.
Doing it this way also makes it irrelevant which individual textbox raised the event. Instead, you will handle it the same way for all of the textboxes—by completely ignoring all invalid input.
Here's what I'd do:
First, attach a handler method to your textbox's KeyDown event. You can do this from the Properties window in the designer, or you can do it through code, as you have in the question:
textbox[i,j].KeyDown += TextBox_KeyDown;
Then, you need to put the logic into your event handler method that determines if the key that the user just pressed is in the allowed range (A through I), or outside of it:
private void TextBox_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
// Determine if the keystroke was a letter between A and I
if (e.KeyCode < Keys.A || e.KeyCode > Keys.I)
{
// But allow through the backspace key,
// so they can correct their mistakes!
if (e.KeyCode != Keys.Back)
{
// Now we've caught them! An invalid key was pressed.
// Handle it by beeping at the user, and ignoring the key event.
System.Media.SystemSounds.Beep.Play();
e.SuppressKeyPress = true;
}
}
}
If you want to restrict the user to typing in only one letter, you can add code to handle that in the above method, or you can take an even simpler route and let the textbox control handle it for you automatically. To do that, set the MaxLength property of the textbox to true, either in the designer or through code:
textbox[i,j].MaxLength = true;
Check the text of the sender instead of whatever textbox[1,1] is.
Use the sender parameter of the event handler to identify the textbox responsible for the event.
The first thing that will help you is casting the sender of your event to a TextBox like this:
(Also, as Cody Gray said, this is a TextBox_Validated event, not a KeyPress event so I've renamed it appropriately)
private void TextBox_Validated(object sender, EventArgs e)
{
TextBox tb = sender as TextBox()
if (sender == null)
return;
bool bTest = txtRegExStringIsValid(tb.Text.ToString());
ToolTip tip = new ToolTip();
if (bTest == false) {
tip.Show("Only A-I", tb, 2000);
tb .ext = " ";
}
Next you need to actually get into that code for every textbox. There are two obvious approaches to that, you can either assign the eventhandler to each textbox in the array or you can use a custom textbox which always does this validation and then add that to your array.
Assign eventhandler to textboxes
foreach(var tb in textbox)
{
tb.Validated += new EventHandler(TextBox_KeyPress);
}
Create custom textbox control
Create the custom text box control (Add a user control to the project) and then just use it exactly as you would a normal textbox.
public partial class ValidatingTextBox: TextBox
{
public ValidatingTextBox()
{
InitializeComponent();
}
protected override void OnValidating(CancelEventArgs e)
{
bool bTest = txtRegExStringIsValid(this.Text.ToString());
ToolTip tip = new ToolTip();
if (bTest == false)
{
tip.Show("Only A-I", this, 2000);
this.Text = " ";
}
}
private bool txtRegExStringIsValid(string textToValidate)
{
// Exactly the same validation logic as in the same method on the form
}
}

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