We Keep Coding

QR Code contains TAB that sets focus on the next object in WPF

I have created a program that uses a Powerscan PD9530 scanner to register serialnumbers of different parts into a database. But one of the parts contains TAB between different parts of the serialnumber. I need to get the entire serialnumber into a selected TextBox, but the TABS in the QR-Code makes the focus jump to the next TextBox and presses some buttons as it jumps along.
My Program is able to identify what part is scanned to put it in the right location in the database.
The serialnumber format is like this: "+ 002761 M0610500HQ 000001917 "
with the spaces being TAB
I have tried:
private void TxtPa_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Tab)
{
txtPa.Focus();
}
}
I was hoping that this would set the focus back to the TxtPa TextBox when the TAB space get input, but the next piece of numbers after the TAB gets put into the next TextBox instead.

I've managed to figure it out thanks to your help.
I added "e.Enabled = true" and it pretty much solved my initial problem.
I only had to declare the String that read from the TextBox outside the function
string OSRAM = "";
private void TxtPa_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Tab)
{
OSRAM = OSRAM + " " + txtPa.Text;
serl[5] = OSRAM;
e.Handled = true;
}
}
Thank you very much for the help

How to take automatically value from textbox

I am trying to scan a card to a textbox and I want to take value from the textbox when the scanning complete.
When I try this its execute before scan completion.
private void txtUserName_TextChanged(object sender, EventArgs e)
{
string val = txtUserName.Text;
}

You need to choose some special character which will indicate completion of a scan.
Currently your code will store in val variable any text that is in TextBox after changing text in it. Including situation when you are typing last character of your input, so your code would work eventually.
But I'd suggest choosing for example \t character and then checking for scan completion indicated by this character using KeyPress event (because event arguments have KeyChar, which is very useful):
private void txtUserName_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar != '\t') return;
// handle your event
}

How do I send text to the display on a DataLogic Gryphon barcode scanner using Micosoft POS.NET

I'm working on a barcode scanner application in c# and are using Microsoft POS 1.14 to communicate with the scanner. Barcode scanning works fine but now our customers want to use scanners with a display to show "friendly" text instead of the barcode.
I have not found any code example on how to do this, I hope it is possible. Maybe the "DirectIO"-command could be used but unfortunatly I could not get it to work.
In DataLogic's Product Reference Guide you can find "escape-sequences" that could be sent to the scanner probably this could be the solution.
My question is how... Is there any POS-expert out there that could have a solution to my problem?
Best regards

After having done something similar based on the scanner (or magnetic card reader) basically being a keyboard and I could listen and handle those keypresses as they were in a certain pattern... I've dont eh following......
Key press pattern...
;123123?
I wrote the following code to notice the key press at teh main form level, then open / focus the appropriate form field on the ";". Then take all the other key presses until "?" and take that as "enter".
private void EPOSForm_KeyDown(object sender, KeyEventArgs e) {
//this captures ";" and gives focus to the member ref for input also escape key
if (e.KeyValue == 186 || e.KeyValue == 27) {
textBox.Focus();
}
}
private void textBox_KeyDown(object sender, KeyEventArgs e) {
//this captures ";" and ignores it
if (e.KeyValue == 186 || e.KeyValue == 191 || e.KeyValue == 27)
return;
}
private void textBox_TextChanged(object sender, EventArgs e) {
if (textBox.Text.IndexOf(";") != -1) {
//prevents typing of the last char
textBox.Text = textBox.Text.Replace(";", "");
textBox.Focus();
textBox.SelectionStart = textBox.Text.Length;
}
if (textBox.Text.IndexOf("?") != -1) {
//prevents typing of the last char, but assumes it mean "enter"
textBox.Text = textBox.Text.Replace("?", "");
textBox.Focus();
textBox.SelectionStart = textBox.Text.Length;
//click button
}
}

How to set TextBox to only accept numbers?

I have already checked other questions here but the answers are not related to my issue. the following code allows textbox1 to only accept numbers if the physical keyboard (laptop) is pressed:
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
char ch = e.KeyChar;
if ( !char.IsDigit(ch))
{
e.Handled = true;
}
}
but this is not what I wanted (I dont use physical laptop keyboard).
As shown in screenshot, I have windows form with buttons and a textbox. I designed this keyboard and it works well but I want textbox1 to only accept numbers and the ".".
There are only two lines of code inside each button (and only code in the project) which is:
private void buttonName_Click(object sender, EventArgs e)
{
// each button only has this code.
textBox1.Focus();
SendKeys.Send(buttonName.Text);
}
I know how to set txtbox to accept numbers if the physical (laptop ) keys are pressed but here in this case I have control buttons in windwos form and I want to set textBox1 to only accept numbers and the ".". Please help in how to achieve this. Thank you

Declare a string variable at form level, use it to store the last valid text and to restore it when an invalid text is entered on the TextChanged event of your textbox.
string previousText;
public Form1()
{
InitializeComponent();
previousText = String.Empty;
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
int dummy, changeLenght, position;
if (!String.IsNullOrWhiteSpace(textBox1.Text) && !int.TryParse(textBox1.Text, out dummy))
{
position = textBox1.SelectionStart;
changeLenght = textBox1.TextLength - previousText.Length;
textBox1.Text = previousText;
textBox1.SelectionStart = position - changeLenght;
}
else
{
previousText = textBox1.Text;
}
}
position and changeLenght are used to keep the cursor where it was before restoring the text.
In case you want to accept numbers with decimals or something bigger than 2147483647, just change dummy to double and use double.TryParse instead of int.TryParse.
private void textBox1_TextChanged(object sender, EventArgs e)
{
int changeLenght, position;
double dummy;
if (!String.IsNullOrWhiteSpace(textBox1.Text) && !double.TryParse(textBox1.Text, out dummy))
{
...
}
}

Suppose button1 is your button control, you could do this:
private void allButtons_Click(object sender, EventArgs e)
{
Button btn = sender as Button;
char c = btn.Text[0]; //assuming all buttons have exactly 1 character
if(Char.IsDigit(c) || c == '.')
{
//process
textBox1.Focus();
SendKeys.Send(btn.Text);
}
//otherwise don't
}
I'm assuming you put this in a common handler, to which you already wired all your buttons (i.e. allButtons_Click).
Problem with this approach, it allows you to type values like 0.0.1, which are most likely invalid in your context. Another way to handle this is to process TextChanged event, store previous value, and if new value is invalid, restore the old one. Unfortunately, TextBox class does not have TextChanging event, which could be a cleaner option.
The benefit of you determining the invalid value is modularity. For example, if you later decide your user can enter any value, but only numbers can pass validation, you could move your check from TextChanged to Validate button click or similar.
Why users may want that - suppose one of the options for input is copy/paste - they want to paste invalid data and edit it to become valid, for example abc123.5. If you limit them at the entry, this value will not be there at all, so they now need to manually paste into Notepad, cut out in the invalid characters, and paste again, which goes against productivity.
Generally, before implementing any user interface limitation, read "I won't allow my user to...", think well, whether it's justified enough. More often than not, you don't need to limit the user, even for the good purpose of keeping your DB valid etc. If possible, never put a concrete wall in front of them, you just need to guide them correctly through your workflow. You want users on your side, not against you.

How to execute a method in C# WinForms if a textbox value equals a predermined length

I have a form where a user enters a 4 digit pin number. When the pin number is entered, I would like to call my method automatically once the last number of the pin number is pressed. I am assuming this needs to be done in a keydown event on the textbox.
Here is what I tried so far.
private void txtPinNumber_KeyDown(object sender, KeyEventArgs e)
{
if (txtPinNumber.Text.Trim().Length == 4)
{
SendKeys.Send("{ENTER}");
if (e.KeyCode == Keys.Enter)
Verify_Pin();
}
}
It seems to work but the user has to press an addition key to execute the method. What am I missing?

There's no reason to press Enter programmatically and then check for it. Just call the other method.
Also, the KeyDown event fires before the Text property changes to reflect the most recently typed character, so you'll have to place that code in a different event.
Use TextChanged or KeyUp.
private void txtPinNumber_TextChanged(object sender, KeyEventArgs e)
{
if (txtPinNumber.Text.Trim().Length == 4)
Verify_Pin();
}

You said
When the pin number is entered, I would like to call my method automatically once the last number of the pin number is pressed.
So you can simply do this in the KeyUp event of your textbox
private void txtPinNumber_KeyUp(object sender, KeyEventArgs e)
{
if (txtPinNumber.Text.Trim().Length == 4)
Verify_Pin();
}
BTW, it is advisable to let user press enter and then you run the code. Because it can be that user accidentally presses the last number wrong.