Develop Reference

.Focus() doesn't work in TextChangedEvent

I have implemented some code in my Windows Form C# program, and the problem is that I want to have the following code in TextChangeEvent instead of the Validating event, but the .Focus() and .Select() methods don't work.
What is the solution for this?
private void jTextBox5_TextChangeEvent(object sender, EventArgs e)
{
if (jTextBox5.TextValue != "John")
{
jTextBox5.Focus();
}
}

You could try:
private void jTextBox5_TextChangeEvent(object sender, EventArgs e)
{
if (jTextBox5.Text.ToUpper().Trim() != "JOHN")
{
((Textbox)sender).Focus();
}

If you're trying to enforce that the user can only type the word "John" into the textbox, and you want to validate this on each key press, then you can do something like the following code, which examines the current text, one character at a time, and compares each character to it's counterpart in the word "John".
If a character doesn't match, then we set the text to only the substring of characters that do match, so they can continue typing:
private void jTextBox5_TextChanged(object sender, EventArgs e)
{
var requiredText = "John";
// Don't allow user to type (or paste) extra characters after correct word
if (jTextBox5.Text.StartsWith(requiredText))
{
jTextBox5.Text = requiredText;
}
else
{
// Compare each character to our text, and trim the text to only the correct entries
for (var i = 0; i < jTextBox5.TextLength; i++)
{
if (jTextBox5.Text[i] != requiredText[i])
{
jTextBox5.Text = jTextBox5.Text.Substring(0, i);
break;
}
}
}
// Set the selection to the end of the text so they can keep typing
jTextBox5.SelectionStart = jTextBox5.TextLength;
}

c# TextBox how to get the last letter of a string?

private void inputBox_KeyPress(object sender, KeyPressEventArgs e)
{
stringScan();
var regex1 = new Regex(#"[^+^\-^\b^\r\n]");
var regex2 = new Regex(#"[^0-9^+^\-^/^*^#^\b^\r\n]");
if (ListBox.Items.Count == 0 && string.IsNullOrWhiteSpace(inputBox.Text))
{
if (regex1.IsMatch(e.KeyChar.ToString()))
{
e.Handled = true;
toolTip1.Show("Plus or minus first then followed by numbers.", inputBox, 1500);
}
}
else
{
if (regex2.IsMatch(e.KeyChar.ToString()))
{
e.Handled = true;
}
}
}
public void stringScan()
{
char last_char = inputBox.ToString()[inputBox.ToString().Length - 1];
Console.WriteLine(last_char);
}
How can i get the last letter/number of a string?. Its really hard to explain so I'll show some screenshots.
the output should show "0" not "1".
It always show the "previews last" and not the latest one that i typed in the textbox.

Remember, when the event inputBox_KeyPress is raised, the typed key isn't added yet. Also, don't use regex for this. It will be overcomplicated.
Try the TextChanged event.

Text box key change will be executed every time u change the content of the text box
So for every value u enter u will be calling the string scan
This can be limited if u know what length the text is going to be

What about you try this:
public void stringScan()
{
String last_char = inputBox.ToString();
Console.WriteLine(last_char[last_char.Length-1]);
}

If you want last typed char I suggest:
private void inputBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
Console.WriteLine(e.Text);
}
If you want last char in textbox I suggest TextChanged event as already told by Jeroen van Langen:
private void inputBox_TextChanged(object sender, TextChangedEventArgs e)
{
string inputString = ((TextBox)sender).Text;
char lastChar = inputString.Last();
Console.WriteLine(lastChar);
}
Hope code samples help you
Edit:
Now I get that you probably want to get integer from textbox, if that's the matter, Get integer from Textbox could help you, code sample:
private void inputBox_TextChanged(object sender, TextChangedEventArgs e)
{
string inputString = ((TextBox)sender).Text;
int valueFromTextBox;
if (int.TryParse(inputString, out valueFromTextBox))
{
//parsing successful
}
else
{
//parsing failed.
}
}

Need some tips for my application

I'm doing an exchanger application and I need help to combine the amount I have put in, in the textBox and the currency in the combobox to another textBox when I click on the Assign/Add button.
I have been stuck with this for while now.
I have tried many things, maybe I'm overthinking the problem.
private void asignBttn_Click(object sender, EventArgs e)
{
Currency currency1 = valueFromCoBox.SelectedItem as Currency;
if (valueFromCoBox.Text == string.Empty) { return; }
foreach (var item in resultBox.Text)
{
}

I didn't quite understand what is the type Currency that you pull from the select box (I'm not really familiar with the .net type).
But if it is a custom class it'll be easier.
private void asignBttn_Click(object sender, EventArgs e)
{
Currency currency1 = valueFromCoBox.SelectedItem as Currency;
if (valueFromCoBox.Text == string.Empty) { return; }
//// how about this?
resultBox.Text = valueFromCoBox.Text + currency1;
Let us know.

c# apply same rules to all textboxes

I have several text boxes and would like to format them all the same way with these rules:
// limits to number, control keys, and decimal
// goes to the next text box when enter
private void tb_text1_KeyPress_1(object sender, KeyPressEventArgs e)
{
string newString = Regex.Replace(tb_text1.Text, "[^.0-9]", "");
tb_text1.MaxLength = 6;
e.Handled = (!char.IsDigit(e.KeyChar) && !Char.IsControl(e.KeyChar) && e.KeyChar != '.');
if (e.KeyChar == (char)(Keys.Enter))
{
this.GetNextControl(ActiveControl, true).Focus();
}
}
// removes restricted chars
private void tb_text1_Enter(object sender, EventArgs e)
{
tb_text1.Text = Regex.Replace(tb_text1.Text, "[^.0-9]", "");
}
// applies format at exit
private void tb_text1_Leave(object sender, EventArgs e)
{
tb_text1.Text = string.Format("{0,-6} [Ohm]", decimal.Parse(tb_text1.Text));
}
What is the best way? create a new text box class based on the text box?
Thanks.

Replace in methods your "tb_text1" variable to the "((TextBox)sender)", and now You can use Your code for any textbox.

It is very easy to do it with javascript . Please try that. I have done it i'm not able to find piece of that code right now . It is worth the effort because it will be very fast and will be running on client side.

Textbox for price/cash/currency on C#

I have a problem that is haunting me for a while. I tried some solutions but they didn't worked.
I have a textbox that is for cash input ($999,99 for example). However I need to automatically input the "," and "." to display the value correctly.
I tried two solutions. One of them is this:
private void tx_ValorUnidade_TextChanged(object sender, EventArgs e)
{
string value = tx_ValorUnidade.Text.Replace(",", "").Replace("R$", "");
decimal ul;
//Check we are indeed handling a number
if (decimal.TryParse(value, out ul))
{
//Unsub the event so we don't enter a loop
tx_ValorUnidade.TextChanged -= tx_ValorUnidade_TextChanged;
//Format the text as currency
tx_ValorUnidade.Text = string.Format(System.Globalization.CultureInfo.CreateSpecificCulture("pt-BR"), "{0:C2}", ul);
tx_ValorUnidade.TextChanged += tx_ValorUnidade_TextChanged;
}
}
The result, however, is very weird.
The other one is this:
private void tx_ValorUnidade_KeyUp(object sender, KeyEventArgs e)
{
if (!string.IsNullOrEmpty(tx_ValorUnidade.Text))
{
System.Globalization.CultureInfo culture = new System.Globalization.CultureInfo("en-US");
int valueBefore = Int32.Parse(tx_ValorUnidade.Text, System.Globalization.NumberStyles.AllowThousands);
tx_ValorUnidade.Text = String.Format(culture, "{0:N0}", valueBefore);
tx_ValorUnidade.Select(tx_ValorUnidade.Text.Length, 0); *
}
}
This one kinda works, but there is a issue: if the user wants to insert somethink like $10,00 it can't. It also crashes after 5 numbers.
For original reference, I got the 2 codes from other questions here.
How can I fix it? Am I using the examples wrong? Any thought is welcome.

I think you will be better off when formatting when the user moves to the next control, e.g. like below. Otherwise it will be very confusing as the text will change itself as the user is typing:
private void textBox1_Leave(object sender, EventArgs e)
{
Double value;
if (Double.TryParse(textBox1.Text, out value))
textBox1.Text = String.Format(System.Globalization.CultureInfo.CurrentCulture, "{0:C2}", value);
else
textBox1.Text = String.Empty;
}

Some people might want to actually format a textbox as they type. So this is my solution if anyone is looking for one.
It actually assumes you are entering one digit at a time so therefore as you press "1" it assumes "$0.01" and when they press "2" it then assumes "$0.12" and so on and so forth.
I could not find anything online about formatting as they typed. It has been tested and if any errors let me know.
private void textBox1_TextChanged(object sender, EventArgs e)
{
//Remove previous formatting, or the decimal check will fail including leading zeros
string value = textBox1.Text.Replace(",", "")
.Replace("$", "").Replace(".", "").TrimStart('0');
decimal ul;
//Check we are indeed handling a number
if (decimal.TryParse(value, out ul))
{
ul /= 100;
//Unsub the event so we don't enter a loop
textBox1.TextChanged -= textBox1_TextChanged;
//Format the text as currency
textBox1.Text = string.Format(CultureInfo.CreateSpecificCulture("en-US"), "{0:C2}", ul);
textBox1.TextChanged += textBox1_TextChanged;
textBox1.Select(textBox1.Text.Length, 0);
}
bool goodToGo = TextisValid(textBox1.Text);
enterButton.Enabled = goodToGo;
if (!goodToGo)
{
textBox1.Text = "$0.00";
textBox1.Select(textBox1.Text.Length, 0);
}
}
private bool TextisValid(string text)
{
Regex money = new Regex(#"^\$(\d{1,3}(\,\d{3})*|(\d+))(\.\d{2})?$");
return money.IsMatch(text);
}
To make it look nice I'd recommend starting the text box with the text $0.00 on the form load like so:
private void Form1_Load(object sender, EventArgs e)
{
textBox1.Text = "$0.00";
textBox1.SelectionStart = inputBox.Text.Length;
}

Just a slight modification to GreatNates answer.
private bool KeyEnteredIsValid(string key)
{
Regex regex;
regex = new Regex("[^0-9]+$"); //regex that matches disallowed text
return regex.IsMatch(key);
}
and insert this method into the textboxs preview input event like this.
private void TextBox1_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
e.Handled = KeyEnteredIsValid(e.Text);
}
That way you make sure that you can't make any mistakes when typing anything. You are limited to numbers only with my methods, while nates methods are formatting your string.
Cheers.

We can try following one as well.
txtCost.Text = String.Format("{0:c2}", myObj.Cost);

I struggled with this for hours too. I tried to use maskedTextBox but that was just clunky for the users to enter text. I also didn't like having to deal with the masking for calculations. I also looked into using the databinding formatting but that just seemed overkill.
The way I ended up going was not to use a TextBox for inputting numbers. Use the NumericUpDown object instead. No need conversion and you can set your decimals and thousands commas in the properties if you like ;) I set my increment to 1000 since i was dealing with income.
Do be aware that the .Text that comes through will have commas when there is a penny decimal and amount over 1000 (i.e. 1,000.01) , otherwise the decimal and trailing 0s are dropped.
I also found this short and sweet solution which worked well but was unneccesary with numericUpDown. You can put this on leave event.
Decimal val;
if (Decimal.TryParse(TxtCosPrice.Text, out val))
TxtCosPrice.Text = val.ToString("C");
else
MessageBox.Show("Oops! Bad input!");

This is my solution, it puts only dots, not money symbol. Hope can help somenone.
private void textBox1_KeyUp(object sender, KeyEventArgs e)
{
e.SuppressKeyPress = TextBox2Currency((TextBox)sender, e.KeyValue);
}
private bool TextBox2Currency(TextBox sender,int keyval)
{
if ((keyval >= 48 && keyval <= 58) || keyval == 46 || keyval == 8)
{
int pos = sender.SelectionStart;
int oriLen = sender.Text.Length;
string currTx = sender.Text.Replace(".", "").ToCurrency();
int modLen = currTx.Length;
if (modLen != oriLen)
pos += (modLen - oriLen);
sender.Text = currTx;
if ( pos>=0)
sender.SelectionStart = pos;
return false;
}
return true;
}