How to wait for user input inside function using c# - c#-4.0

Question

I have One Window application by Which User Can Print Their Product Barcode Value And Also Can Scan it,
Now i am searching for some threading or some other way,
If user Enter 5 value for Print after Printing First value, Function wait for user input in text box (i call textbox up event for capturing scanning value)
and if value is correct so, my function continue its execution or wait until user Scan Proper barcode,
so how can i make method or function which can wait for user input and then continue executions.
private void myFunction1()
{
for (i = 0; i < intPrintNo; i++) // Number Of Print
{
// here I write Code For Print My Barcode
// Now I want to wait For user Input in my text box
jumphere :
txtBarcode.Text = "";
txtBarcode.Enabled = true;
txtBarcode.Visible = true;
txtBarcode.Focus();
if (keyUp()== false)
{
txtBarcode.Text = "";
txtBarcode.Enabled = true;
goto jumphere;
}
// If return True than for loop Continue for next Printing
}
}

Answer 1

From what i've understood from your question, you want to print the barcode of value specified by the user and then user can scan the same to verify if printed properly or not.
You can achieve this functionality in Windows forms using following steps
User enters the value (to print barcode) in txtInput
Presses print button (btnPrint)
The print button event handler will first disable itself and the input textbox (btnPrint.Enabled = txtInput.Enabled = false; Application.DoEvents();) and then print the barcode and set focus on textbox txtVerify.
User will scan the barcode in textbox txtVerify.
User will click on verify button (btnVerify) which will compare the value in txtInput and txtVerify.
If everything fine, clear the txtInput, txtVerify, enable txtInput and btnPrint, set focus to txtInput for next value
If error, do the needful.
EDIT: As per OPs comment (minimum user effort)
You can change the setting of barcode scanner to suffix newline (Enter) after every scan (you can find how to do this setting in the manual provided with the barcode)...... so now,
step 4. User will scan the barcode in textbox txtVerify (the scanning will provide Enter press at the end of scan). txtVerify.TextChanged event handler will check if key pressed in Enter, if so, call the code to verify (compare the values in txtInput and txtVerify)
step 5. Remove this step from above
step 6. If everything fine, clear the txtInput, txtVerify, enable txtInput and btnPrint, set focus to txtInput for next value
step 7. If error, do the needful.
Also, you can modify the first textbox to print the barcode when user presses enter key (so, no need to click on Print button)
So, after above modifications, the user will enter the text press enter (this will print barcode) then scan (as focus is already in txtVerify). If everything is fine, new value can be entered.
To reset the screen, you can provide a 'Reset' button.
Glad to help! Please remember to accept the answer if you found it helpful.