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use regular expression
MCAD
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what do u mean by regular expression? i was told to do onkeypress event on textbox.. how do i start doing that, do u know?
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nidhelp wrote:
what do u mean by regular expression?
A regular expression is a language that's used to define the format of an input string. Google will tell you more.
nidhelp wrote:
i was told to do onkeypress event on textbox.. how do i start doing that, do u know?
In the designer, click on the text box, in the properties, tick the lightning flash. I'd suggest that textchanged is perhaps a better event to go for. What's your level of experience here ? Are you just starting ? Why do you have this requirement ? Is it homework ( I'm still happy to help you if it is ) ?
Once you have an event that tells you the text has changed, a regular expression is still the way to know the format of the string. Look up Expresso on this site, it's an app that helps you build regex, and a great learning tool.
Christian Graus - Microsoft MVP - C++
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What's your level of experience here ? Are you just starting ? Why do you have this requirement ? Is it homework?
i am v new to c#. for more details, i've replied u in my other post regarding tab page that day. =)
ok i've looked through some codes on regular expression.. do i have to simply copy paste the codes i need in my program and it'll know what format i want, or do i've to go somewhere to click/select/fill in something to specify my format of an input string?
also how's a textchanged better than onkeypress?
thanks!
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nidhelp wrote:
i am v new to c#. for more details, i've replied u in my other post regarding tab page that day. =)
Ah... welcome back 
BTW, you can highlight my replies and hit the 'Quote selected text' button to get the format you see when I quote you.
nidhelp wrote:
do i have to simply copy paste the codes i need in my program and it'll know what format i want, or do i've to go somewhere to click/select/fill in something to specify my format of an input string?
\d is a number, \w is a character in a word ( alpha ), and {} allow you to show number of items
If this regex matches anything
\d\w{6}\d
and the number of characters is 8, then you have a number, six letters and a number. Was that the format you wanted ?
Christian Graus - Microsoft MVP - C++
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o thanks for teaching me about quote selected text =)
my format is a letter, 7 numbers, a letter
>> \w\d{7}\w correct?
hmmmm.. i need to ensure that the user only types s/S or f/F for the first letter.. how is that possible?
i clicked on the lightning button n looked through the onkeypress already but it still gives me no clue as to how to even use the onkeypress to do my app..
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nidhelp wrote:
hmmmm.. i need to ensure that the user only types s/S or f/F for the first letter.. how is that possible?
A regex can contain more specific info, [] is used for character groups.
[sSfF]\d{7}[sSfF]
will do it. OnKeyPress will give you a function that runs when a key is pressed. In that function, you need to get the text from the textbox and check it. Something like this:
TextBox tb = sender as TextBox;
string input = tb.Text;
if (input.Length == 9 && System.Text.RegularExpressions.Regex.Match(input, @"[sSfF]\d{7}[sSfF]").Success)
{
// The string is correct
}
else
{
// Don't forget that unless the length is 9, they could still be entering, so don't put a warning box here. A better place for that would be the lose focus event.
}
Christian Graus - Microsoft MVP - C++
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Christian Graus wrote:
// Don't forget that unless the length is 9, they could still be entering, so don't put a warning box here. A better place for that would be the lose focus event.
I recommend the Validating event. That's what it's for, and if you set e.Cancel = true, focus won't leave the control.
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
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in >> TextBox tb = sender as TextBox
what is sender? i have to replace sender with some other things right?
can i write the conditions which u typed under private bool.
do i need to type something in OnKeyPress property?
thanks i've learnt quite a lot from u =)
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nidhelp wrote:
what is sender? i have to replace sender with some other things right?
No, the event has an object called sender. Did you not create the event yet ? I did it this way instead of using a variable directly precisely so that you didn't need to change the code I gave you.
nidhelp wrote:
can i write the conditions which u typed under private bool.
You can set up a property if you'd like. Then you need to change the variable name though.
nidhelp wrote:
do i need to type something in OnKeyPress property?
OnKeyPress lets you check every time the user types. If they are pressing a button to do something and you need THEN to check if the code is valid, forget the events ( although the Validating event may be worth a look, I know nothing about that ), and then it would make sense to make it a private property, to encapsulate this piece of functionality.
nidhelp wrote:
thanks i've learnt quite a lot from u =)
No worries, always glad to help.
Christian Graus - Microsoft MVP - C++
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sorry but i dont get u... do i create KeyPressEvent n put those codes inside it?
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If you want to validate whenever a key is pressed, yes. If you always need a valid code, then I'd go with the code that accepts nothing else ( unless it's some sort of licence key ). If you don't always need it, then I'd not bother with the event, because people can type what they like, you can proceed with and without a valid value ( although it would be better for the UI to tell people the value was not valid ). Then you can instead do this check when the button is pressed that causes the value to be used.
I'm about to leave for 2 days, so that's the end of my help for now. Good luck...
Christian Graus - Microsoft MVP - C++
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If you are using a textbox, you can handle the key press event and process the necessary logic to allow/disallow certain characters from being entered. Here's some code below. I have not tested it but the logic is there i believe:
private void tbEditor_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
if(e.KeyChar == (char)8)
e.Handled = false;
else if(Char.IsLetter(e.KeyChar) == true && (tbEditor.Text.Length == 0 || tbEditor.Text.Length == 8))
e.Handled = false;
else if(Char.IsDigit(e.KeyChar) == true && (tbEditor.Text.Length > 0 || tbEditor.Text.Length < 8))
e.Handled = false;
else
e.Handled = true;
}
<font=arial>Weiye Chen
Life is hard, yet we are made of flesh...
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hi
im not supposed to disable any keys from being entered into the textbox.. the user is free to type n my app shd only open up a form when he types in a correct format..
correct format is a letter, 7 numbers, a letter..
i also have to make sure the first letter is S or s or F or f.. as long as the first letter is not correct, the form will not open..
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I got this to work with a combination of both ways. Using the Validating method, and a RegularExpression.
Just to confirm - the pattern you wanted was:
s,S,f or F at the start
7 numbers
and upper or lowercase letter at the end
which I represented as the reg ex: [sSfF]\d{7}[a-zA-Z]
In the form designer, highlight your textbox and look at the Properties grid. Swap it to events using the little lightning symbol. Scroll until you see an event named Validating. Double-Click inside the textbox to the right of the event name - this should do 2 things
1) Jump to the code-behind view
2) Enter the stub of an event...mine started life looking liek this:
private void textBox1_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
}
The two arguments passed to this method are very useful.
sender - is the thing that sent this event (the textbox in this case)
e - is the event arguments, in this case of type CancelEventArgs. This type of event arguments has a Cancel property which can be set to true for this event to indicate that the contexts of the text box are NOT valid (hence the event name validating.
So back to the problem. In pseudo-code:
if textbox is not valid<br />
set Cancel to true
this can be done in the following two lines
TextBox tb = sender as TextBox;<br />
e.Cancel = !Regex.Match(tb.Text,@"[sSfF]\d{7}[a-zA-Z]").Success;
However, to explain this
1) Cast the sender to type TextBox
TextBox tb = sender as TextBox
2)Determine if its text is valid:
bool isValid = Regex.Match(tb.Text,@"[sSfF]\d{7}[a-zA-Z]").Success;
3)if not valid, set Cancel to false
e.Cancel = !isValid;
end result: until you enter the correct sequence of characters into the textbox you are unable to tab out or close the form.
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i just finished reading n doing the top half of what u typed only but i want to thank u already.. u r v detailed n i cld follow through n understand your instructions easily.. hey thanks! =)
i'll be reading n doing the bottom half after i type this.. hopefully it works..
=)
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nidhelp wrote:
u r v detailed n i cld follow
If only I could understand your "english" anywhere near as well as you could understand my explaination we'd both be happy.
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u r v detailed n i cld follow >> you are very detailed and i could follow =)
do u understand my "english" or do i have to type properly? sorry if you didnt.
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Generally, this kind of !33tspeek is not really welcome here.
On the one hand it gives us the impression of talking to a 14-year old, on the other hand it's rather rude if people take their time to answer your problems and you don't even spend enough time to write properly.
mav
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yes ok i understand now..
i just thought that people would understand !33tspeek easily..
so sorry about it..
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I need to clarify this...
My code WAS like this:
private void button3_Click(object sender, System.EventArgs e)
{
if(Validate(textBox4.Text))
{
if (tabControl1.TabPages.Contains(tabPage6)) {
}
else
{
tabControl1.TabPages.Add(tabPage6); }
}
else
{
// show invalid username dialogbox
}
}
// Conditions to determine whether a tab page is to be displayed when Go button is clicked
private bool Validate(string Val)
{
if(Val!="")
{
if(Val.Length==9||Val.Length==12)
{
return true;
}
else
return false;
}
else
return false;
}
I donno how to edit my codes with the codes u gave me to make my app run..
can u teach me what's going on?
In fact, I also need to open a tab page if the text input is made up of 12 digits..
Therefore, a tab page should open when the text input is \d{12} OR [sSfF]\d{7}[a-zA-Z]..
The user is allowed to key in anything he wishes but the tab page will not open if what he entered doesnt meet the conditions set..
Thank you!
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I'll continue to help when you eliminate txtspk from your posts. Go click the modify link on the above and type in English, and i'll check back very soon.
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who can tell me how to active FormB from FormA, A(MainForm) and B(has been minimized) are in one application,but are not parent and child.
If FormA and FormB are belong to diffent applicaions what should i do to achieve the same goal?
thanks! ^_^
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First
to activate Maximize or Minimize form from another one
windows forms has property called WindowState
so code somthing like this
anotherForm.WindowsState=FormWindowState.Normal<br />
MCAD
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if form B has existed, how could i know, and how to find it.
thanks!
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