how to set propery bindings

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Hi
I made a form with dynamically added textboxes and labels. is there a way to set property bindings to these so when a user closes and reopens the form the controls and user input will still be there.

I know I can do it with a normal added control but cant work it out for dynamic.

Thanks

Posted 22-Dec-13 23:20pm

Member 10439491

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2 solutions

Solution 2

You have to save the Data somewhere otherwise you won't be able to access it again.
So, store in Database or files and read them again while loading the page.

Posted 22-Dec-13 23:40pm

Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ)

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OriginalGriff · Accepted Answer · 2013-12-22T23:38:00

Solution 1

No, there is no automatic way to do this: you have to store the information on what controls you added where in nonvolatile storage (ie, on disk) either with the Application settings file, or via a file of your own devising. Then reload the infor and re-add the controls next time you open the form.

"I'm not sure I know what you mean
I know how to use for each loop I think
like this?

VB

For Each ctrl In FlowLayoutPanel1.Controls
     If TypeOf ctrl Is TextBox Then
         If ctrl.Name = ask Then
             ctrl.Dispose()
         End If
     End If
 Next ctrl

I don't really understand how to write that code"

Yep - that's a For Each loop and I'll just digress into them a bit.
For Each is one of the simplest kinds of loop - it works with (almost) every collection from Arrays to Lists, and so on (basically anything which is in the IEnumerable "club" can go in a For Each loop, but don;t worry about that just yet)
What is does is takes each item in the collection in turn, and executes the code in the loop using that instance. It's like a pile of coins: if you want to know how many are Heads and how many are Tails, you take each one of the top of the pile in turn and look at it, write down the Head or Tail and move on to the next.

In your code the Collection is FlowLayoutPanel1.Controls and each Control is put into the ctrl variable in turn.

You can do this with strings as well:

VB

Dim lines As String() = File.ReadAllLines("D:\Temp\myData.txt")
For Each line As String In lines
    ...
Next

So where you want to start is:

VB

Dim lines As String() = File.ReadAllLines("D:\Temp\myData.txt")
For Each line As String In lines
    ' Process each line into two control texts
    Dim input As String = "label data|textbox data"
    Dim parts As String() = input.Split("|"C)
    Dim forTheLable As String = parts(0)
    Dim forTheTextbox As String = parts(1)
    ' And create the controls
    ...
Next

Then all you have to do is extract the code from your click event handler into here and you're done.

Does that make sense?

Posted 22-Dec-13 23:38pm

OriginalGriff

Updated 24-Dec-13 4:22am

v2

Comments

Member 10439491 23-Dec-13 6:28am

Hmmm how do I do that? sorry still learning :)

OriginalGriff 23-Dec-13 7:10am

There are a *huge* number of ways to do that.
Do you know how to use settings? Text files, CSV, XML or databases?
We don't know what your skills or experience are, so we can;t just say "Do this" because the solution I would use might confuse you horribly, or not be appropriate to your application...

Member 10439491 23-Dec-13 7:26am

Well the simple answer would be no I don't know. I've only made 1 pretty basic form for personal use (income and outgoings) it adds up all income and adds up all outgoings and puts the value in a textbox. there's a few other things but that's basically what it does. I have no idea what the best way to store all the data entered would be. I guess a added button for save/load or something like that

OriginalGriff 23-Dec-13 7:47am

If youre trying to store data, then that is something where you need to be quite careful - because controls are pretty easy: they have fixed properties that you need, like the Location and what type of control it is.
Data gets to be another cup of fun-and-games, because it can be pretty much anything your user wants to type, and that can make it more complex. And the difficulty is never in storing the data, it's in getting it back...:laugh:
There are a couple of simple ways to store and retrieve data, but what I'm going to suggest is all about storing sets of data, rather than individual items - because I think that is what you are trying to do.
Using textboxes and labels dynamically is probably not the best way to do this (as you will learn later there are much better controls for that kind of thing, but I'll not confuse you more than I have to)
So the first thing to do is collect your data together so you can process it using loops of some form. Do you know what an Array is? List? DataTable? The simplest form of storage is to just output your data to a file, with each textbox or label on a separate line.
Assuming you know what an array is, if you have an array of strings, you can store them all easily with:
File.WriteAllLines("D:\Temp\MyFile.txt", myArrayOfStrings)
and read them all back with:
Dim myArrayOfStrings = File.ReadAllLines("D:\Temp\MyFile.txt")

(Sorry if this comes over at all patronising - the problem is that I don't know how much you do know, So I'm trying to find out what I can tell you that will work, but now bog you down in concepts you haven;t met yet.)

Member 10439491 23-Dec-13 8:06am

I can use arrays sort of, I don't know how to use list or datatable. I originally was using an array of all my textboxes because I thought I would know how many textboxes and labels there would be and made an array of there names but after using my form I realised I wouldn't actually know how many textboxes or labels there would be so that why I changed to dynamically adding them to a scrollable flowlayoutpanel.
Here is my code to add textboxes and labels

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

Dim ask As String
ask = InputBox("Please name your Income", "Income")
If ask = Nothing Then
Exit Sub
End If
Dim label As New Label()
Dim count As Integer = FlowLayoutPanel1.Controls.OfType(Of Label)().ToList().Count
label.Location = New Point(10, (25 * count) + 2)
label.Size = New Size(176, 20)
label.Name = "label_" & (count + 1)
label.Text = ask
FlowLayoutPanel1.Controls.Add(label)

Dim textbox As New TextBox()
count = FlowLayoutPanel1.Controls.OfType(Of TextBox)().ToList().Count
textbox.Location = New System.Drawing.Point(60, 25 * count)
textbox.Size = New System.Drawing.Size(80, 20)
textbox.Name = ask
textbox.Text = CDec(IIf(Decimal.TryParse(textbox.Text, Nothing), textbox.Text, "0"))
FlowLayoutPanel1.Controls.Add(textbox)

AddHandler textbox.KeyPress, AddressOf TextBox_keypress
AddHandler textbox.Click, AddressOf textbox_click

If label.Text <> "" Then
Dim a As String = label.Text
label.Text = (StrConv(a, VbStrConv.ProperCase))
End If
End Sub

Ive done it like that so if a user wants to remove something with my remove button they type the exact name of what the control is example: Wages and the textbox and label will be removed.

I don't know if I should think about redoing things if I have just made things very difficult for myself.

OriginalGriff 23-Dec-13 8:22am

Well...maybe a little, but it was a good idea!
If you look at the FlowLayoutPanel, you can add as many controls as you want to it's Controls just by calling the Add method - as you are in your code sample. That's because it is a List or Control objects and that behaviour comes built in.
You can create your own lists and use them in the same way you would an array, but without having to worry about the number of items in it:
Dim myList As New List(Of String)()
myList.Add("Hello")
myList.Add("There")
myList.Add("World")
Console.WriteLine(myList(1))
So you don't need to use a flow layout panel to hold the actual data, just to display it (and there are better controls that that, once you start playing with Collections such as List in earnest)
Do you know how to create classes and properties yet?

Member 10439491 23-Dec-13 12:07pm

No I don't know how to create them, will that help me? If I started adding things to a list wouldn't I need to know how many controls im going to use? for instance if I wanted 99 textboxes (I don't :)) would I have to white mylist.add("Income1") upto 99? or am I getting confused?

OriginalGriff 23-Dec-13 12:40pm

If you don't know how to create them, Then I don't want to confuse you, so just stick with the simple stuff for the moment. (I mentioned them because later when you meet them you will find you can create a list of your class and display the whole list as a sort of "mini-spreadsheet" with a single line of code! Each property becomes a column, and each class instance becomes a row. Nice!)

That's the whole idea of a List - you don't have to know in advance how many items you are going to add. Think of it like a shopping list. If you are anything like me, you wander round the kitchen going "Milk? No. Bread? Yes, Onions? Yes, Cat food? No..." and building up a list of things you don't want to forget when you get to the shops. You don't know in advance how many things you are going to need, so you just add them as you go. And if you then find a loaf of bread in a cupboard, you can remove it from your list without having to rewrite the whole thing.

That is pretty much what you are doing already - the FlowLayoutPanel1.Controls property is a List and you add them manually at the moment each time the user clicks the button.
So add a class level List of strings (i.e. create it outside any method) and when your user clicks the button, add the data to your list as well at the bottom of your method.
myList.Add(String.Format("{0}|{1}", label.text, textbox.Text))
What that does is create a string which has the label Text and the Textbox Text together, separated by a '|' so you can break it later.

Then, when you close your app, handle the FormClosing event, and save your data:
File.WriteAllLines("D:\Temp\MyData.txt", myList);

Member 10439491 23-Dec-13 13:52pm

I think I understand, I shall give it a shot and see what happens :)

OriginalGriff 23-Dec-13 13:58pm

:thumbsup:!

Member 10439491 23-Dec-13 15:11pm

Ok so I have a file now with my user input in but cant seem to load it back into the boxes. when I reload my form all boxes have vanished again

OriginalGriff 23-Dec-13 15:21pm

That's because we haven't done that bit yet!
Start off by reading the text back into an array - File.ReadAllLines will do it for you.
Then loop through each line in the array - you know what a For Each loop is, yes?
Use String.Split to "break" the line:
Dim input As String = "label data|textbox data"
Dim parts As String() = input.Split("|"C)
Dim forTheLable As String = parts(0)
Dim forTheTextbox As String = parts(1)
You can then use code just like you have already to "regenerate" the controls.
If you put this in the Form.Shown Event it will be done automatically when your application runs.

Hint: Take your existing code to add the controls, and move it into a method that you pass two strings. Then call that from both places and it should work straight away!

Member 10439491 23-Dec-13 15:35pm

I'm not sure I know what you mean
I know how to use for each loop I think
like this?
For Each ctrl In FlowLayoutPanel1.Controls
If TypeOf ctrl Is TextBox Then
If ctrl.Name = ask Then
ctrl.Dispose()
End If
End If
Next ctrl

I don't really understand how to write that code

OriginalGriff 23-Dec-13 16:00pm

I can't write code at the moment - I'm on a tablet and it's a PITA to write code - so I'll explain tomorrow when I'm back at the PC, OK?

Member 10439491 23-Dec-13 16:01pm

that sounds great, you have been an amazing help

OriginalGriff 24-Dec-13 10:23am

Answer updated!

Member 10439491 24-Dec-13 14:23pm

That makes perfect sense, im going to be away for a few days for xmas but will try it as soon as im back and let you know. thank you very much

OriginalGriff 24-Dec-13 14:30pm

You're welcome!
Have a good break, don't do anything I haven't done (which admittedly isn't going to restrict you much :laugh: )

Member 10439491 26-Dec-13 13:06pm

OK so I've come back :) ive tried it out and it seems to work... ish. what exactly do I put for the label.text = and textbox.text = because at the moment if I put wages I just get wages|0 when I reload the form. ive tried a few different things

Member 10439491 26-Dec-13 15:17pm

ive just found another problem. mylist is only storing the value 0 for my textbox from

textbox.Text = CDec(IIf(Decimal.TryParse(textbox.Text, Nothing), textbox.Text, "0"))

not the actual value entered into the box

Member 10439491 26-Dec-13 17:02pm

Ok so I think ive found a way around it but ive had to use 2 .txt files. one to store labels and one to store textboxes. it works but I would still like to know how you would get over it

Member 10439491 26-Dec-13 17:51pm

nope not working :(

OriginalGriff 27-Dec-13 4:22am

Good grief! You thought carefully about that line of code, didn't you? :laugh:
textbox.Text = CDec(IIf(Decimal.TryParse(textbox.Text, Nothing), textbox.Text, "0"))
There are a couple of problems here...as you may have noticed! ;)
TryParse is the first one - why try to convert something and throw away the actual answer? (In a more civilised language like C# you can't even write that - because it's rather nasty...)
So, if TryParse says it's a valid decimal value in the string, you use the string value you started with, or "0" if it is bad...
And then convert that to a decimal.
Finally you implicitly convert that back to a string again to stick it back in the textbox.

Um. Didn't you get the feeling you were making things a little more complicated than you needed to? :laugh:
If Not Decimal.TryParse(textbox.Text, Nothing) Then
textbox.Text = "0"
End If
Is slightly clearer...

If you look at the code fragment I wrote three days ago, it gives you the text to put in the label and the textbox: they are in two variables specially named for that purpose. "forTheLable" and "forTheTextBox" were meant to be clues :laugh:

Have a look, and if it still doesn't work post up the whole code fragments you are currently using and I'll see where you have got to.

Member 10439491 27-Dec-13 6:21am

I tried using forthelable and forthetextbox as I thought it was obviouse but when I reload the form it only returns "label data" and "textbox data" not the actual values

OriginalGriff 27-Dec-13 6:39am

So...you didn't spot that the "input" bit was meant to be your data rather than a fixed string like my example then?

Member 10439491 27-Dec-13 6:47am

Um did I mention I'm new to this hehe. I kind of worked that out after the value wasn't right but I have no idea what I'm mentioned to put in its place

OriginalGriff 27-Dec-13 6:50am

Ok...you have read your data from the file yes? And it's got the label and teh textbox text, joined together with '|' characters?
So, when you read it, you used a For Each loop to work on each line at a time?
So inside the loop feed the line to the code and let it Split it back into label and textbox data.
Does that make sense?

Member 10439491 27-Dec-13 7:12am

It makes sense but I'm not sure how to put that into code. I think I've gone wrong with the original code. I'm getting confused :( would label date be {0} and textbox data be {1} then when it splits I should get actual values rather then label data and textbox data?

OriginalGriff 27-Dec-13 7:21am

Let's go back a stage or two, and make sure we both know where you are!
You have a file with the label and textbox data combined, yes?
If so, paste a couple of lines so I can see it.
Then, also show the code you have to read the file, and the loop you are using to process each line.

Member 10439491 27-Dec-13 7:23am

Well I'm on my ipad at the moment but as soon as I get on the pc I will do

OriginalGriff 27-Dec-13 7:35am

Yep! It's a PITA trying to code on a tablet - I have the same problem with my Nexus 7...

Member 10439491 27-Dec-13 7:59am

ok so I got it working with
Private Sub Form1_Shown(sender As Object, e As EventArgs) Handles MyBase.Shown
Dim lines As String() = File.ReadAllLines("c:\users\carl\documents\MyData.txt")
For Each line As String In lines
Dim parts As String() = line.Split("|"c)
Dim forTheLable As String = parts(0)
Dim forTheTextbox As String = parts(1)

Dim label As New Label()
label.Size = New Size(176, 20)
label.Text = forTheLable
FlowLayoutPanel1.Controls.Add(label)

Dim textbox As New TextBox()
textbox.Size = New Size(80, 20)
'textbox.Name =
textbox.Text = forTheTextbox
FlowLayoutPanel1.Controls.Add(textbox)

Next

End Sub

but I still am unsure how to get my actual user input of the textbox. all the labels are right but my textboxes are just displaying the value 0

Member 10439491 27-Dec-13 8:16am

If Not Decimal.TryParse(textbox.Text, Nothing) Then
textbox.Text = "0"
End If
this is just to put a "0" in the textbox on creation (thinking about it, it should be in textbox.leave probably and just set textbox.text ="0")

This isn't the value I want to be saving. I want to save the value that a user has entered. hmmm

OriginalGriff 27-Dec-13 9:27am

So where do you do this?
And what does the data you saved look like?

Member 10439491 27-Dec-13 12:24pm

basically you click a button and it adds a label and textbox the label text being whatever is entered into the inputbox and that stays the same. but the textbox value can be changed by a user.
example
Wages 0
more 0
lots 0

so the way im saving the labels is fine but I think I made need to add something to save the text entered.

they save file layout is
if I wrote
wages 10
more 15
lots 20

would save as
wages|0
more|0
lots|0

OriginalGriff 27-Dec-13 14:04pm

Yep - the save data is wrong, so we need to look at that.
Have you tried editing the text file by hand to prove that the "read it out" code works?

Post the code you used to save it!

Member 10439491 27-Dec-13 14:10pm

Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing

File.WriteAllLines("C:\MyData.txt", MyData)

End Sub

And editing it manually works so I just need to direct it to get the actual values

OriginalGriff 27-Dec-13 14:15pm

:sigh:
This has "long night" written all over it...
Ok, my fault - I should have said. The code we need is where you add the values to MyData, though that is a lovely little event handler! :laugh:

Member 10439491 27-Dec-13 14:17pm

lol fun fun! so where do we begin?

Member 10439491 27-Dec-13 14:19pm

the first value into MyData is the creation of the label and textbox on the button click. the second from a textbox validation or leave event or something like that?

OriginalGriff 27-Dec-13 14:38pm

Something! So what does the code around
MyData.Add(...
look like?

Member 10439491 27-Dec-13 14:42pm

MyData.Add(String.Format("{0}|{1}", label.text, textbox.Text))

OriginalGriff 27-Dec-13 15:05pm

"...the code around..."

Context is important!

I think I know what you want to do.
Remove all reference to MyData from your code, and add another loop to your FormClosing handler.
This loop needs to look at each label and each Textbox and add their Text properties together - can you do that? Or do you need help?

The reason you want to do it there is that you want the values the user has written when teh program closes - not any values you put in when you creates them. Make sense?

Member 10439491 28-Dec-13 0:55am

i gave it a go but im not sure how to do that

OriginalGriff 28-Dec-13 4:01am

You do know - you pretty much have all the code already, you just need to think about it for a couple of minutes and tie the bits together: it's not new stuff you need.
Have a go - I'm not going anywhere! :laugh:

Member 10439491 28-Dec-13 5:43am

I was trying code like
For each ctrl as control in flowlayoutpanel1.controls
If type of control is textbox then
........

Then I'm not sure where to go from there. I know what I want to do. I want to add that ctrl.text to mydata list.

I can do that but I'm not sure how to add a label to the list joining to textbox and label with a |.

Code might not be perfect as I'm on ipad

OriginalGriff 28-Dec-13 6:03am

You have the right idea! That is definitely the way to go...all you need to do is "match up" labels and textboxes.
So...outside the loop, create a String variable.
Inside the loop, if the control is a Label, set the variable to the Text property, and append a "|".
If it is a Textbox, append the Text property and add the variable to the MyData List. Then set the variable to an empty string.

Sorted!

Member 10439491 28-Dec-13 9:01am

Still on ipad.... So
Dim Text As New System.Text.StringBuilder()
For ctrl as control in flowlayoutpanel1.controls
If typeof ctrl is textbox then
Text.append (ctrl.text)
Text.append ("|")
If typeof ctrl is label then
Text.append (ctrl.text)
Mydata.add(string.format({0},text))
Text = nothing
End if
End if
Next ctrl

Something like that?

I've not tried it yet, that's just a guess

OriginalGriff 28-Dec-13 9:24am

Other way round - You need the Label first then the Textbox so that the data in teh file will be:
Label|Textbox
That code will give you
TextBox|Label
BTW: Well done on using a StringBuilder! You can also get the string out of it like this:
Mydata.add(Text.ToString())
which is a little easier to read. Take a :thumbsup: anyway!

Member 10439491 28-Dec-13 9:32am

Yea I noticed that after I wrote it but it was to much effort to change ha. I'll try it out in a little while

Member 10439491 29-Dec-13 10:07am

I finaly got it working with

Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
Dim text As String

For Each ctrl As Control In FlowLayoutPanel1.Controls
If TypeOf ctrl Is Label Then
text = Nothing
text = ctrl.Text
End If

If TypeOf ctrl Is TextBox Then
text = text & "|" & ctrl.Text

MyData.Add(text.ToString())
End If

Next

File.WriteAllLines("C:\MyData.txt", MyData)
End Sub

because I have 4 flowlayoutpanels that I want to do the exact same thing for am I able to add it all to the same list? or will I need a new list for each one. and will I need a new save file for each one?

OriginalGriff 29-Dec-13 10:34am

You can use the same list, and the same file. But...that does make it complicated, because you have to add data to the file to say which panel it is intended for. For the moment, I'd be tempted to use four lists, and four files.
You don't need the line:
text = Nothing
because the following line overwrites the value anyway.
I'd more it to after:
MyData.Add(text.ToString())
Because you don't need the content any more.
Oh, and you don't need the ToString in that line either - text is already a string so converting it to a string again does nothing useful! :laugh:

(And well done, by the way!)

Member 10439491 29-Dec-13 10:44am

Well Thank you very much for all your help :) I bet you wish you never answered hehe
thanks again

OriginalGriff 29-Dec-13 11:32am

Well, I didn't think it would take all week, no... :laugh:

The important thing is you did the work, not me - so I assume you have learned something, which is kinda the idea. ;)