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Winforms TextBox keeps value in UserControl

I am making an app in which there are multiple UserControls stacked onto each other. So the elements go like this: MainForm -> User clicks on a UserControl1 on the MainForm which (UserControl1) has a panel on which there is displayed another UserControl2 with a button. When the user clicks on it, it displays another UserControl3 which is then displayed in the panel beneath the button, where finally the user enters some text in the textbox. I need the data from the textbox in the MainForm so I have MainForm and UserControls connected via EventHandlers and pass my ResponseModel in which there is some dat a that I need to pass to MainForm. The first time this works, an item is created and displayed, after the item there is this "button" (User controls) displayed, in case the user wants to create another one. But then comes the problem when the user types in a different text for a new item, it creates an item with the same text!! Like the textbox was never changed (I have a debugging point set on the constructor to see every time that the textbox is empty). Below is some code and an image, for you to see how this should work. Also when I first delete the item it then doesn't work to create a new item for some reason.
This is how I send the data from the last UserControl:
if (tbx_list_name.Text == "")
MessageBox.Show("You can't create new list without a name!", "Can't create new list!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
else
CreateListTextBoxHandler?.Invoke(this, new ListCreationResponseModel() {
Code = id, ListName = tbx_list_name.Text
});
This is how I create the last UserControl which has the textbox:
control.CreateListTextBoxHandler += GetHandlerData;
panel.Controls.Add(control);
And this is how I get the data one stage down (this practice continues through couple more stages back to MainForm):
public void GetHandlerData(object sender, ListCreationResponseModel e)
{
try
{
panel.Controls.Clear();
CreateListButtonHandler?.Invoke(this, e);
}
catch (Exception ex)
{
_ = new ErrorHandler(ex);
}
}

You seem to have a recursion here. GetHandlerData is added to the CreateListTextBoxHandler event (or delegate) and invokes CreateListTextBoxHandler again, which will call GetHandlerData again...?? But tbx_list_name.Text is passed to the model only once at the top level down to all the other calls.
You can fix this by passing a reference to the textbox instead of the text itself. Then you will always be able to retrieve the current text of the textbox.
public class ListCreationResponseModel
{
private readonly TextBox _listNameTextBox;
public ListCreationResponseModel(TextBox listNameTextBox)
{
_listNameTextBox = listNameTextBox;
}
public int Code { get; set; }
public string ListName => _listNameTextBox .Text;
}
Now, when you retrieve the ListName you don't get a stored value but the actual text of the textbox.
You can create the handler like this:
CreateListTextBoxHandler?.Invoke(this, new ListCreationResponseModel(tbx_list_name) {
Code = id
});

Adding a twin tabPage to tabControl through a user command

I'm a newbie in c# and probably going to ask a very easy question, but I've not been able to find anything on the web to help.
I have a tabControl with a TabPage which is containing a TextBox object; this object, when the event "Text changed" is invoked, will perform the change of the parent tabPage's name.
The textbox where I typed "text changed by me" has a method which is managing changing the name of the tabPage:
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (this.textBox1.Text != "")
this.tabControl2.SelectedTab.Text = this.textBox1.Text;
else
this.tabControl2.SelectedTab.Text = "(no name)";
}
Into the current page menu is contained a control to add a new page, which runs this method when the user click on it:
private void addNewPageToolStripMenuItem_Click(object sender, EventArgs e)
{
int numPagine;
string strPagine;
numPagine = this.tabControl2.TabCount;
strPagine = numPagine.ToString();
this.tabControl2.TabPages.Add("new page" + strPagine);
}
...and here is the output, which is expected since I'm just asking to add a new empty tabPage:
So, my question is: how can I make possible that when the user is clicking on "Add new page", rather than creating an empty new tabPage the program is rather creating a page like the first one (i.e. containing a textbox into the same position which has a method to change the text of the parent tabPage that I have just created?

Here is an example.
//..
// create the new page
TabPage tpNew = new TabPage("new page..");
// add it to the tab
this.tabControl2.TabPages.Add(tpNew);
// create one labe with text and location like label1
Label lbl = new Label();
lbl.Text = label1.Text;
lbl.Location = label1.Location;
// create a new textbox..
TextBox tbx = new TextBox();
tbx.Location = textBox1.Location;
tpNew.Controls.Add(lbl);
tpNew.Controls.Add(tbx);
// add code to the new textbox via lambda code:
tbx.TextChanged += ( (sender2, evArgs) =>
{
if (tbx.Text != "")
this.tabControl2.SelectedTab.Text = tbx.Text;
else
this.tabControl2.SelectedTab.Text = "(no name)";
} );
For more complicated layout you may want to consider creating a user control..
You also may want to create the first page with this code; the, of course with real values for text and positions!
For creating a UserControl you go to the project tag and right click Add-UserControl-UserControl and name it, maybe myTagPageUC. Then you can do layout on it like on a form. A rather good example is right here on MSDN
The problem is that is has no connection to the form, meaning you'll have to code all sorts of references to make it work..
I'm not really sure if you may not be better off writing a complete clonePage method instead. It could work like the code above, but would loop over the Controls of the template page and check on the various types to add the right controls..
It really depends on what is more complicated: the Layout or the ties between the pages and the form and its other controls..

Making an indexed control array?

Has C# indexed control arrays or not? I would like to put a "button array" for example with 5 buttons which use just one event handler which handles the index of all this 5 controls (like VB6 does). Else I have to write for each of these 5 buttons one extra event handler. And if I have 100 buttons, I need 100 event handlers? I mean something like that:
TextBox1[i].Text="Example";
It could make coding definitely easier for me to work with control arrays. Now I have seen, that C# at least has no visible array functionality on user controls and no "index" property on the user controls. So I guess C# has no control arrays, or I must each element call by known name.
Instead of giving 100 TextBoxes in a for loop 100 incrementing values, I have to write:
TextBox1.Text = Value1;
TextBox2.Text = Value2;
...
...
TextBox100.Text = Value100;
A lot of more work + all these 100 event handlers each for one additional TextBox extra.

I know I'm a little late to this party, but this solution will work:
Make a global array:
TextBox[] myTextBox;
Then in your object's constructor, after the call to
InitializeComponent();
initialize your array:
myTextBox = new TextBox[] {TextBox1, TextBox2, ... };
Now you can iterate your array of controls:
for(int i = 0; i < myTextBox.Length; i++)
myTextBox[i].Text = "OMG IT WORKS!!!";
I hope this helps!
Pete

As I mentioned in comment to a solution by HatSoft, C# Winforms does not allow you to create control arrays like old VB6 allowed us. The nearest I think we can get to is what HatSoft and Bert Evans in their posts have shown.
One thing that I hope would satisfy your requirement is the event handler, you get a common event handler and in the event handler when you typecast the "sender" you get the control directly just like you would in VB6
C#
TextBox textBox = sender as TextBox;
VB6
TextBox textBox = TextBox1[i];
So the only trouble you might have is wiring those 100 TextBoxes to a single event handler, if you are not creating the controls dynamically through code rather creating it manually at design time then all one can suggest is group them in a container like say Panel. Then on Form Load wire them all up to a single event handler like this:
foreach (Control control in myTextBoxPanel.Controls)
{
if(control is TextBox)
control.TextChanged += new EventHandler(control_TextChanged);
}

Just create one handler and point all the buttons to it.
var ButtonHandler = (sender, args) => {
var clicked = (Button)sender;
if (clicked.Text == "whatever")
//do stuff
else
//do other stuff
};
button1.Click += ButtonHandler;
button2.Click += ButtonHandler;
Alternatively, if you are creating controls in code, you could use one of the techniques specified in this answer.

Instead of giving 100 TextBoxes in a for loop 100 incrementing values, I have to write:
for(int i = 0; i <100; i++)
{
TextBox t = new TextBox(){ Id = "txt_" + i, Value = "txt_" + i};
t.TextChanged += new System.EventHandler(this.textBox_Textchanged);
Page.Controls.Add(t);
}
//and for event on TextChanged
private void textBox_Textchanged(object sender, EventArgs e)
{
TextBox textBox = sender as TextBox;
if (textBox != null)
{
////
}
}

Another thing to note: if you really need to edit 100 strings on one form, you should probably think about whether 100 text boxes is really the best way to do it. Perhaps a ListView, DataGridView, or PropertyGrid would be better suited.
This applies almost any time you think you need a huge array of controls.

If you are working with Web Forms and not MVC, you can acces a collection of controls on the page as shown in Using the Controls Collection in an ASP.NET Web Page. Essentially the controls collection is a tree with the page hosting the first level of child controls and some items having children of their own. See How to: Locate the Web Forms Controls on a Page by Walking the Controls Collection for an example of how to follow the tree.
Also, see How to: Add Controls to an ASP.NET Web Page Programmatically.
You can use the same event handler for multiple items as long as the signature required is the same.
For Windows Forms this is nearly identical since they're based on similar architectural models, but you'll want Control.Controls Property and How to: Add Controls to Windows Forms.

Keeping it simple:
TextBox[] keybox = new TextBox[16]; //create an array
for (int i=0; i<16; i++)
{
keybox[i] = new TextBox(); //initialize (create storage for elements)
keybox[i].Tag = i; //Tag prop = index (not available at design time)
keybox[i].KeyDown += keybox_down; //define event handler for array
}
private void keybox_down(object sender, KeyEventArgs e)
{
int index = (int)((TextBox)sender).Tag //get index of element that fired event
...
}

how to avoid rebinding grid each time the control is initialized?

I've created a custom user control with a grid. I'd like to bind this grid once, and use it over and over again in my app. If I put the binding within the control, the data is retrieved as many times as I use the control. How do I bind it only once??
public ClientLookUp()
{
InitializeComponent();
vw_clientsTableAdapter.Fill(dsclientlkup.vw_clients); //This occurs as many times as I have the user control, instead of just once.
}

Well anything you put in the constructor will be executed every time you construct the object!
What about providing an Initialize method that you can call whenever you need to reload the data??

If you want to load the data only once, then load it either into a static variable or a separate class that is referenced by the control.

If you really want to use the same single grid in your control over and over, you could create a single, static grid, and have your ClientLookUp constructor add it to the right place—Panel, or whatever—whenever a new one is created.
Before you go do this road however, ask yourself if this is really what you want to do. Having the same identical grid existing in many places may cause you problems down the road. If you want to support in-grid editing, you'll find that changing one value changes the identical value in all your other grids..
EDIT
I tried getting the below code to work, but I'm not sure this approach will be possible. It seems as though the minute you try to attach the same UI element into more than one place, it gets moved out of the last place you put it; it doesn't look like you can have the same grid being in more than one place at once. This makes sense when you think about it.
Here's the code I tried. Maybe it will be of some use to you.
public UserControl1()
{
InitializeComponent();
this.Controls.Add(myStaticGridView);
myStaticGridView.Dock = DockStyle.Fill;
}
static DataGridView _staticGrid;
public DataGridView myStaticGridView
{
get
{
if (_staticGrid != null)
return _staticGrid;
_staticGrid = new DataGridView();
_staticGrid.Columns.Add("A", "A");
_staticGrid.Columns.Add("B", "B");
_staticGrid.Columns.Add("C", "C");
_staticGrid.Columns[0].DataPropertyName = "A";
_staticGrid.Columns[1].DataPropertyName = "B";
_staticGrid.Columns[2].DataPropertyName = "C";
_staticGrid.DataSource = new[] {
new { A = "someA", B = "someB", C = "someC"},
new { A = "someA", B = "someB", C = "someC"},
new { A = "someA", B = "someB", C = "someC"},
new { A = "someA", B = "someB", C = "someC"},
};
return _staticGrid;
}
}
And then loading the control like this:
private void button1_Click(object sender, EventArgs e)
{
flowLayoutPanel1.Controls.Add(new UserControl1());
}

Click a custom control and show some variables related to it in another control

in my Win Forms app I create an array of dynamic custom controls inside a loop. These, lets call them 'boxes', are like my basic pieces of information. I also create string arrays in other parts of the code that contain the information of this 'boxes', so that for example string[3] is a variable of box[3] and so does stringa[3], stringb[3], stringc[3]... all the arrays with the same index are related to the box with that index. Hope I make myself clear.
Only 2 of this strings are shown in 2 labels inside each custom control 'box' in the array, but the others are there because I want to make something so that when the user clicks one of these controls the other strings can be shown in another control. Sort of something like "More Information...". All the 'boxes' in the array need to have the same event handler because I create +100.
To put it more into context, each custom control 'box' in the array shows the Symbol and the Price of a stock and I want that when the user clicks on each stock more quote information is shown on another special control which is like a placeholder for "More info".
I am thinking of 2 ways to do it:
If I could "detect" the index of the clicked control (which is the same in the strings related to it), I could just set this to an int j and all I have to do is show all the strings a,b,c... with index j. Unfortunately I cannot find a way to do this, maybe it is not even possible.
The other way I have thought is to create some properties for my custom control which "store" this variables, and in my app instead of assigning strings I would set properties for each control, which I could later retrieve when the control is clicked. I haven't tryed this because I don't know exactly how to do it.
What do you think? Do you know how can I achieve this or do you have a different idea that will work? Please help! Thanks in advance.

It's kind of a broad implementation question since there are countless ways you could implement something like this.
If you are creating two collections, one with the buttons and one with the information, you potentially could just assign each of the buttons 'Tag' properties to point to the corresponding info and assign a generic OnClick event handler that displays the info.. something like:
infoControl.text = ((InfoClass)((Button)Sender.Tag)).pieceOfInformation;
But again there are many ways to do this, and the choice comes down to how you store your information.

For your first method, you could have a property of your custom control that is the index.
public class Box : Control
{
// ...existing code
private int index;
public int Index
{
get
{
return index;
}
set
{
index = value;
}
}
}
OR
For your second method, you could have a property of your custom control that is the additional info string.
public class Box : Control
{
// ...existing code
private string extraInfo;
public string ExtraInfo
{
get
{
return extraInfo;
}
set
{
extraInfo = value;
}
}
}
In either case, you could then access the proper information right in your click handler for the "box".

i don't know about the first way - got to noodle around more, but in the second way you can extended your custom or built-in control: for example:
public class ExtendedLabel: Label
{
public string[] MoreInfo { get; set; }
}
and initialize it
public TestForm()
{
InitializeComponent();
ExtendedLabel label = new ExtendedLabel();
label.MoreInfo = new string[] { "test" };
this.Controls.Add(label);
label.AutoSize = true;
label.Location = new System.Drawing.Point(120, 87);
label.Name = "label1";
label.Size = new System.Drawing.Size(35, 13);
label.TabIndex = 0;
label.Text = label.MoreInfo[0];
}
And later in your event handler you can use the inside information