Develop Reference

How to create tab pages content dynamically in windows forms?

I am using windows form to build an app that draws the form controls based on the connected device dynamically. So I have a tab control and when the user select tab3 for instance the tab page content will be drawing based on connected device for example add two text boxes and a button. How can I do this. I would like also to know how to position those controls after they are created.
private void tabPage3_Click(object sender, EventArgs e)
{
TextBox text = new TextBox();
this.tabPage3.Controls.Add(text);
}

As you just stated, you create your Controls like in your example. Positioning is achieved by the Left and Top Properties of your freshly created control. BUT, my advise is, it will be easier to use predefined UserControls and add them dynamically, because I think you don't have nearly unlimited types of devices.
If you are curious how Visual Studio Designer is creating those code, just look up Designer.cs in InitializeComponent()

Docking an existing QWidget in QWindow

For those who are very familiar with C# or VB.NET using the UserControl component in the .NET Framework (which is the hottest framework in my opinion), you were used to adding several buttons that preview different user controls as follows:
1) First you would prepare an appropriate user interface (contains 3 buttons and a single panel on the right area to view each user control after clicking one of the added buttons).
2) Adding 3 user controls from the solution explorer...
3) Inserting the content on each user control...
4) Implementing code for the 3 buttons on the frmMain.cs as the following (for this implementation we will be implementing the "Welcome" button carrying the object name as welcomeBtn, and the rest will have identical code but different user control names instead):
private void welcomeBtn_Click(object sender, EventArgs e)
{
//Clear up everything from the panel if any item exist(s)...
mainPanel.Controls.Clear();
//Create a new instance of a user control for the button...
UserControl1_Welcome welcome = new UserControl1_Welcome();
//Show up the created instance of the user control
mainPanel.Controls.Add(welcome);
}
5) Finally, the program will end up initially like this when running:
http://i.stack.imgur.com/OENwG.png
** Usage of the program **
When you click on the "Welcome" button for example, the result should be expected to be like this:
http://i.stack.imgur.com/iCyo3.png
... and when you click on a different button, lets say "License Agreement" button, you would expect to see something other than your current selection.
MAIN QUESTION
How can we bring the simplicity of Windows Forms in QT CREATOR by applying the "QDockWidget"?
I have tried inserting the QDockWidget component with no problems, but when I try to do the equivalent .NET code for adding the QWidget inside the QDockWidget:
ui->dockWidget->setWidget(myWidget);
which I think is equivalent to this line of code in C#.NET (correct me if I'm wrong here):
ui.Controls.Add(myWidget);
After using this code, my program won't crash nor shows anything running...
P.S. I'm sorry for linking the images, I don't have 10 reputation for making them show up...

What I want is to have a program that does the same thing with the C# example (showing a user control based on the click of a button).
If you want to show a particular widget based on a button click, I suggest to use a QStackedWidget
A simple example would be like this:
// In the constructor of your CustomWidget
// Create your buttons
QPushButton* firstButton = new QPushButton("First Button", this);
QPushButton* secondButton = new QPushButton("Second Button", this);
QPushButton* thirdButton = new QPushButton("Third Button", this);
// Create your (custom) widgets
QLabel* firstPageWidget = new QLabel("First Label", this);
QLabel* secondPageWidget = new QLabel("Second Label", this);
QLabel* thirdPageWidget = new QLabel("Third Label", this);
// Add them to the stackWidget
/*QStackedWidget* */ m_stackedWidget = new QStackedWidget(this);
m_stackedWidget->addWidget(firstPageWidget);
m_stackedWidget->addWidget(secondPageWidget);
m_stackedWidget->addWidget(thirdPageWidget);
// Insert buttons and stackWidget to CustomWidget
QVBoxLayout* layoutStack = new QVBoxLayout();
layoutStack->addWidget(m_stackedWidget);
QVBoxLayout* layoutButtons = new QVBoxLayout();
layoutButtons->addWidget(firstButton);
layoutButtons->addWidget(secondButton);
layoutButtons->addWidget(thirdButton);
QHBoxLayout* layout = new QHBoxLayout();
layout->addLayout(layoutButtons);
layout->addLayout(layoutStack);
setLayout(layout);
// Connect button clicks to slots
connect(firstButton, SIGNAL(clicked()), this, SLOT(onFirstButtonClicked()));
connect(secondButton, SIGNAL(clicked()), this, SLOT(onSecondButtonClicked()));
connect(thirdButton, SIGNAL(clicked()), this, SLOT(onThirdButtonClicked()));
Then you change the currently visible widget in the slots:
void CustomWidget::onFirstButtonClicked() {
m_stackedWidget->setCurrentIndex(0);
}
void CustomWidget::onSecondButtonClicked() {
m_stackedWidget->setCurrentIndex(1);
}
void CustomWidget::onThirdButtonClicked() {
m_stackedWidget->setCurrentIndex(2);
}
Note that if you want the button clicks just to simply change some text (as opposed to change the visible widget), you probably better use a QTextEdit instead of a QStackedWidget, and in the slots call setText("....");
If you have a lot of buttons, you'd better use QSignalMapper to limit the number of slots.
Also, I didn't get why you mentioned QDockWidget since they have a quite specific usage:
The QDockWidget class provides a widget that can be docked inside a QMainWindow or floated as a top-level window on the desktop.
QDockWidget provides the concept of dock widgets, also know as tool palettes or utility windows. Dock windows are secondary windows placed in the dock widget area around the central widget in a QMainWindow.
If you simply want a separate window, you're probably looking for a QDialog
How to do this with QtDesigner:
First you would prepare an appropriate user interface (contains 3 buttons and a single QStackedWidget on the right area to view each user control after clicking one of the added buttons).
Adding 3 pages for the user controls in the stack (+ one for the "empty" page if you really need that). If you want to design the Controls in separate UI Files / Only in Code (instead of all controls in your MainFrame), you would add plain QWidgets and promote them to the appropriate specific widget type
Inserting the content on each user control...
Implementing code for the 3 buttons on the frmMain.cpp/.h as the following (for this implementation we will be implementing the "Welcome" button carrying the object name as welcomeBtn, and the rest will have identical code but different user control names instead):
void FrmMain::on_welcomeBtn_clicked() {
ui->stack->setCurrentWidget(ui->welcomeWidget);
}
Select the "empty" page at as the current page in the designer, so the program will end up initially like this when running: (your screenshot)
When you click on the "Welcome" button for example, the result should be expected to be like this: (your second screenshot)

In my opinion, Miki's answer is the only correct approach to this use case (using a QStackedWidget).
For sake of completeness, I'll demonstrate how the same Clear and Add method as used in .NET is done in Qt:
// Assume controlPanel is a QWidget where you want to place the items
// Assume that controlPanel has set a layout (e.g. QHBoxLayout)
// Clear: Remove all Items from layout
QLayoutItem *child;
while ((child = controlPanel->layout()->takeAt(0)) != NULL) {
delete child;
}
// Now widgets are still there, but not layouted. Delete them explicitly
foreach (QWidget * w, controlPanel->findChildren<QWidget*>()) {
w->deleteLater();
}
// Now controlPanel is cleared
// Add new control
controlPanel->layout()->addWidget(new MyNewControlWidget);

First is, we can not force how other framework works to another one. Each framework has its flow and design.
What I am understand is you want to show another widget to the main window.
If you want to use the QDockWidget, its says on the documentation like this :
void QDockWidget::setWidget(QWidget * widget)
Sets the widget for the dock widget to widget.
If the dock widget is visible when widget is added, you must show() it explicitly.
Note that you must add the layout of the widget before you call this function; if not, the widget will not be visible.
Please share here you code of myWidget, so we can try to help you to figure out what is wrong.
On my side, I can achieve it by add the QVboxLayout on your ui->dockwidget and add QLabel with emtpy string and when you want to show myWidget just call ui->dockwidget->vboxlayout->replaceWidget(label, myWidget);

Add and read Multiple textboxes

What is the best way to create and read multiple textboxes in a windows form? In my application, I have a windows form where customer can enter multiple addresses, email addresses
Right now I have a form like this,
TextBoxAddress1 TextBoxEmail1
TextBoxAddress2 TextBoxEmail2
.....
.....
.....
TextBoxAddressN TextBoxEmailN
For this I dragged and dropped multiple controls on a form and named each one of them.
If I use this method I had to write lengthy code to see if first row (TextBoxAddress1 TextBoxEmail1) is filled for validation and even for reading I had to write many lines of code.
Is there a better to way achieve this?

You can use the following code to add a TextBox dynamically to your form:
private int m_CurrTexboxYPos = 10;
private List<TextBox> m_TextBoxList = new List<TextBox>();
private void CreateCheckBox()
{
m_CurrTexboxYPos += 25;
TextBox textbox = new TextBox();
textbox.Location = new System.Drawing.Point(0, m_CurrTexboxYPos);
textbox.Size = new System.Drawing.Size(100,20);
Controls.Add(textbox);
m_TextBoxList.Add(textbox);
}

I would have a listbox/listview with your emails and Add/Edit/Delete buttons which show a popup form - the logic for validating emails, etc. would then be in the one place and your list can grow without you ever needing to add controls to the form.
You could dynamically create textboxes - but you end up writing code to make sure they layout nicely on the form, etc. - having some type of list is easier IMO and also lends itself to binding (e.g. to an email object)

Dynamically adding controls is pretty simple, provided you can use DockStyle and an exclusive container for them (e.g. a Panel). If you can't use DockStyle, then you need to write logic to determine Location and Size (which isn't fun).
On a simple form, I have two buttons and a panel, Button1 adds a new TextBox to Panel1, Button2 iterates through the controls in Panel1 and then checks that they are the correct type or throws an exception. This is where you you would put validation or reading logic. Panel1 needs to have AutoScroll = true; otherwise you will run controls off of the viewable screen.
This concept can be switched for anything that inherits from UserControl (all .Net native controls or your own custom controls).
private void button1_Click(object sender, EventArgs e)
{
TextBox NewEmailBox = new TextBox();
NewEmailBox.Name = "NewEmailBox" + this.panel1.Controls.Count;
NewEmailBox.Dock = DockStyle.Top;
this.panel1.Controls.Add(NewEmailBox);
}
private void button2_Click(object sender, EventArgs e)
{
foreach (Control item in this.panel1.Controls)
{
if (item is TextBox)
{
//Do your reading/validating here.
}
else
{
throw new InvalidCastException(string.Format("{0} was in Panel1 and is of type {1} not TextBox!", item.Name, item.GetType()));
}
}
}

Write a user control for each of the groupings you need. at least one One for address, one for email etc. then all of your validation, calls to your database access is contained in a single location
That is just good design. this way if you have multiple tabs for things like Home Information, Work Information, Emergency Contact Information, you can just place them on the form. This is pretty common for a user profile.
Then a listview for each grouping on a user profile page or whatever, that has edit/delete/add then popup a dialog with the appropriate user control in it.

Most simply, ListBox adove TextBox with Button.
Also you can use DataGridView, BuiltIn functionality for Add\Edit\Delete.
Here using DataGridView (ShowHeader set to false, EditMode to On Enter, with one Column with AutoSizeMode in Fill property)

The less of repeatable code you have, the better programmer you are.
Whenever you see a pattern (something what is repeatable), you could and you should try to optimize it. Unless it's something too small to worry.
In your case, determine first what is the basic of repeatable thing. Do you always have to enter address and email address? Then combine them into a control, which can carry out validation. Do you have to use this control often (or repeat N times)? Then maybe it make sense to switch to a list instead (ListBox, ListView or DataGridView).
Are you too lazy to bother configuring things? Then just optimize something what is obviously going to repeat: put validation into common method and call it from each TextBox event. Or make own TextBox with method build-in. Or do validation at once in the Ok button event by using loop.. or not by using loop.
To find best method you have to first decide best for who. Because customer want something shiny,easy to use, animated, with cats and boobs.. ok, without cats and boobs. The point is: how much work are you willing to put to have it best for the customer.
If I would have to enter table data (or data which form table), I'd go with DataGridView so it would looks like this.. or better:

FieldInfo.CaptionStyle in custom form control not working

I have created a custom form control for use in my Kentico bizform using asp.net and I want to change the field caption style of another field in the form depending upon the value in my custom form control field. So, this is what I have done:
protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
{
if(this.Value == "1")
{
FormEngineUserControl formItem = (FormEngineUserControl)this.Form.FieldControls["Other"];
formItem.FieldInfo.CaptionStyle = "font-weight:bold";
}
}
However, the field caption in the form doesn't seem to get bolded. I tried testing if the event even fires and it does. Infact, if I try something like formItem.Text = "Something" then the texbox gets filled with "Something". While debugging I also noticed that the field caption style does get changed to "font-weight: bold" but that doesn't show on the form. So, there is something wrong with the captionstyle property or the way I am using it. How do I get it to work?
(Please note that the field control "Other" is a text box input)

It's probably too late in Page's lifecycle and the control has already been rendered. Try to set the CaptionStyle earlier (e.g. in control's OnLoad or OnInit) then you'll know with certainty.

User control in windows forms application

I have a simple user control with a text box and label in it. I created public properties to access the text in the textbox when I use the user control in another form.
My problem is the property is returning null value when I call it in the form. Am i missing anything?
My property is as follows::
public partial class UserControl1 : UserControl
{
public UserControl1()
{
InitializeComponent();
}
public string rtnTxtMake
{
get
{
return txtMake.Text;
}
set
{
txtMake.Text = value;
}
}
}
and in the next forms button click event i call the property as follows
UserControl1 Usc = new UserControl1();
string Make = Usc.rtnTxtMake;
MessageBox.Show(Make)

UserControl1 Usc = new UserControl1();
string Make = Usc.rtnTxtMake;
If your user control has by default an empty textbox field, then it seems correct that the above two lines of code would return either null or String.Empty (check via String.IsNullOrEmpty), since you explicitly create a new instance of your user control.
I suppose what you really want is this:
You have inserted a user control into a form in the Designer. Let's call this user control instance ctlUser.
You have a button with a Click event handler. The last few lines of code in your question are from that handler method.
In the handler, you wouldn't create a new instance of your user control (Usc) but refer to the one that you previously inserted into your form, ctlUser. Then things should work as expected.

Your UserControl must be added to the Controls collection of a parent Form/Control before it can be properly initialized. Normally you would not write the code yourself that creates and adds the UserControl.
Instead, first build your project, then go to the Deisgner view of your main form and look at the Toolbox.
Your UserControl name (and an icon) should appear towards the top of the toolbox, and you can simply drag it to the main form. The Windows Forms designer will automatically generate the needed initialization code for you.
You should not create a new instance of your control in your button click event handler. Using the Designer approach to create your control you can simply access the existing instance of your control as follows:
public void button_Click(object sender, EventArgs e)
{
// myUserControl1 has already been created and initialized by the Deisgner generated code
// Note the name 'myUserControl1' is just an example, yours may be different.
string controlText=myUserControl1.rtnTxtMake;
// Or to change the UserControl textbox value
myUserControl1.rtnTxtMake="Testing";
}

What exactly to you mean when you say that the property is returning a null value? Is it actually null, or is your MessageBox simple showing empty?
I quickly duplicated your code and it behaves exactly as expected - the MessageBox shows, but it is empty because the default value of the Text property of the TextBox control is an empty string.
Also, the way you are approaching this is a little unusual.
Firstly, the line:
UserControl1 Usc = new UserControl1();
You do not generally need to instantiate a user control like this. Instead you can drag the control from the toolbox onto the design surface of your form. This will then take care of instantiating and initialising your control for you.
I think that this is actually your problem - when you include the line of code above, you are creating a new instance of the user control, and this is is no way realted to the user control that you have dragged onto the designer.
If you go to the designer view of your form and click on the user control, you should see a properties window somehere. If you do no, then either select it from the View menu, or press F4. In the list of properties, there should be one "Name" this is the programatic name generated for your user control. You can change this here if you want, but when you refer to this control in the rest of the form, this is what you must use.
Secondly, the next two lines:
string Make = Usc.rtnTxtMake;
MessageBox.Show(Make)
You can access the property rtnTxtMake directly. Unless you later need to access the Make string in the rest of your code, then directly accessing the property would usually be considered better style.
MessageBox.Show(userControl.rtnTxtMake);