Develop Reference

Best way to put two Controls on each other and manage their visibility - C#

just for example:
I have two text boxes, both should be in the same location of the form and both are in the same size.
I need to make visible one of them due to a contrition.
OK, everything it perfect:
if (condition)
{
txtBox1.Visible = false;
txtBox2.Visible = true;
}
else
{
txtBox1.Visible = true;
txtBox2.Visible = false;
}
but there is a small problem in design mode! I can not handle and select one of text boxes easily in design mode, one is send to back and one is send to front and accessing them will cause troubles!
How can I manage such situations with control ordering and design? Is my way putting two control on each other right? is there any better way?

One option is to put one TextBox in the location where you want it (let's say textbox1 will be in the right location) and put the other textbox nearby on the designer. This way you can easily select them at design time.
Then, in your Form_Load event, you just put textBox2 at the same location as textbox1:
private void Form1_Load(object sender, EventArgs e)
{
textbox2.Location = textbox1.Location;
textbox2.Visible = false;
A better question might be, why are you doing this? A textbox is a textbox, and you already have one in the position that you want. A textbox is there to collect user input. Why show and hide another one in the same place? The user won't know the difference, and your program state will presumably not care the name of the control in which the user has entered data...

There are multiple ways you can select a single control out of these two. First, by hitting the tab key until you land up on the control you want to select. To optimise the selection you need to first select a different control whose tab order is smaller than both of these.
Second, you can select any control and hit F4 to open properties window. On top of properties window there is a dropdown where you get to see the Control name. You can then choose the control of your choice from this properties window and make changes to properties.

you can do somethings like this, Here is the sample code,
txtBox1.Visible = false;
Point loc = new Point(50, 60); //new location point
txtBox2.Location = loc; //changing location of txtBox2
txtBox2.Visible = true;

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);

Recreate a group of Controls

Let's say that I have a panel with like... 3 controls in it. I may end up adding more controls to it or changing the positioning within that panel. When the program starts, I will programmatically HIDE the control. Eventually, the user can click a button that will create a duplicate of the original panel to populate an area on the form. The button should have the option for another click eventually, meaning that multiple instances of these can come about to populate this area. Remember that these controls may have text labels within them that can be individually set or altered later on, programmatically. I am assuming that to do this program, I need to make a List of controls, maybe a List of panels? I'm not exactly sure how to do this considering the fact that I need multiple controls duplicated multiple times.
Is there a nice, simple way to do this? I really don't want to do the duplication with any kind of 3rd-party package.

You will have to do it in code and therefore it'll be as nice as you can code ;-)
Seriously the course most often taken is to
create a UserControl which is a class related to a form, with the layout you want..
..and add more and more instances of it..
..often to a FlowLayoutPanel, often with AutoScroll
This is pretty nice and simple imo.
Here is a short walk-though..:
first we start, as usual, by picking a nice name for the UserObject class, maybe 'DataPanel' or 'BookItem'..
Next we create it: Go to the project explorer and right-click, choosing Add-New UserControl and give it the class name you chose. I'll use 'BookItem'.
Now you can see the Designer showing you a small empty control.
Look closer: You can also see that in the project explorer ther is now not only the new 'BookItem.cs' file but also the complementary 'BookItem.Designer.cs' and even a 'BookItem.resx' file; so this works very much like creating a new Form..
Let's add a few controls from the toolbox, I chose to add a PictureBox, four Labels and a NumericUpDown.
Have a look at the BookItem.Designer.cs file: Here you can see the very things you see in a Form.Desginer.cs file: All settings and all declarations for all controls you add to the layout. Note especially the declarations (at the bottom of the file): Just like for a Form, all controls by default are declared as private!
We can now work on the layout and script the controls. We also can add functions and properties to the UC, just like a Form.
Please note: Anything you need to access from outside, read from your form or its methods must be public! So if you want to access the NUpDown, let call it 'nud_quantity' you have a choice
You can change its declaration in the BookItem.Designer.cs from private to public or in the Designer by changing the Modifiers property
Or you can write a public function in the UC to get/set its value
Chosing between those two ways is a matter of taste; if other developers will work with the UC class, it will probably be better to put close control over what you expose by writing access methods.
After you have compiled the project you can see the new UC in the Toolbox.
You can now either add it from the Toolbox or
you can add it in code like any control you create dynamically.
Let's look at an example:
Imagine a simple order system in a bookstore: The customer has done a search on the books in our store and is presented with a list of books in a DataGridView 'dgv_bookList', readonly, multiselect. To the right there is a FlowLayoutPanel 'flp_cart' represeting a shopping cart. And we have a command button 'cb_addItems' to add selected books to the cart.
The Button might be scripted like this:
private void cb_addItems_Click(object sender, EventArgs e)
{
if (dgv_bookList.SelectedRows.Count <= 0) return;
foreach (DataGridViewRow row in dgv_bookList.SelectedRows)
{
BookItem book = new BookItem (row);
book.label1.Text = "#00" + book.label1.Text;
book.Name = book.label1.Text;
flp_cart.Controls.Add(book);
}
}
This will add one BookItem for each selected row in the DGV.
A few things to note on the above code:
I pass a DataGridViewRow into the constructor of the UC so it can directly set its labels! This means that, in addition to the parameterless contructor the desginer has built for us, we need to write a second contructor, maybe like this:
public bookItem()
{
InitializeComponent();
}
public bookItem(DataGridViewRow bookData)
{
InitializeComponent();
label1.Text = bookData.Cells[0].FormattedValue.ToString();
label2.Text = bookData.Cells[1].FormattedValue.ToString();
label3.Text = bookData.Cells[2].FormattedValue.ToString();
label4.Text = bookData.Cells[3].FormattedValue.ToString();
}
Instead you could write a public setData(DataGridViewRow bookData) function.
Also note how stupid my labels are named! You can do better than that, I hope!
Also note how I access 'label1' and modify its Text from a Button in the Form; to do that I had to change its declaration in the Desginer.cs file:
private System.Windows.Forms.PictureBox pb_cover;
public System.Windows.Forms.Label label1; // <<----expose this label !
private System.Windows.Forms.Label label2;
private System.Windows.Forms.Label label3;
private System.Windows.Forms.Label label4;
private System.Windows.Forms.NumericUpDown numericUpDown1;
Often preferrable: An access function, maybe like this:
public int quantity() { return (int) numericUpDown1.Value; }
Or, of course a Property:
public int quantity { get { return (int)numericUpDown1.Value; } }
Also note, that I set the Name of the BookData item to some variant of the 1st data item, my book id. This might as well, or better, happen in the constructor; and there should be a check to prevent adding the same item twice..
All in all one can say, that using UserControls is very much like working with Forms, including all the usual ways or tricks for inter-form communication: keep references, expose members, create properties and functions..
One final Note: Like with forms or subclassed controls there is one catch: By placing them in the designer, you assign the designer the responsiblity to display your UC during design time.
This is normally just fine; however it is also possible to introduce subtle mistakes which make it impossible for the designer to display the control. You need to correct these problems before the designer will be able to show a control or any form that contains it. Let have a look at a simple example of such a problem:
Let's script the Paint event of the PictureBox 'pb_cover' in the UC:
public Brush myBrush = null;
private void pb_cover_Paint(object sender, PaintEventArgs e)
{
if (pb_cover.Image == null)
{
Size s = pb_cover.ClientSize;
e.Graphics.FillRectangle(myBrush, 0, 0, s.Width, s.Height);
e.Graphics.DrawLine(Pens.Red, 0, 0, s.Width, s.Height);
e.Graphics.DrawLine(Pens.Red, s.Height, 0, 0, s.Width);
}
}
And let's modify the code in the Add button:
BookItem book = new BookItem (row);
book.label1.Text = "#00" + book.label1.Text;
book.myBrush = Brushes.OliveDrab;
flp_cart.Controls.Add(book);
Now, if you run the program all will be fine. Even if you try to look at the UC in the designer there may or may not be problems. But once you try to open a Form on which the UC was placed, the Desginer will crash and tell you that it can't work, since the Brush is null. Here the remedy is simple: add a default value to the Brush declaration and all is well. Other situations may need a little more thinking..
I don't even run into the problem btw, since I have not placed an instance of BookItem on the Form; they are only created in the Add Button..
I hope that gets you started!

Apply Input Mask for a ToolStripComboBox C#

I was just wondering if anyone has come across how to apply an input mask for a Tool Strip Combo Box in C#?
My drop down box gets populated over time with IP addresses, and I would like to restrict what the users are able to write in (Ex: can only input 3 '.'s, only numbers, etc).
So if anyone is able to help out I would really appreciate it!
Thanks in advance.
Edit
My design has changed so I now need to have a ToolStripComboBox

You could try catching the KeyUp event, then check that the input is valid. If not revert it to the last valid input. You would probably want to do something similar with the Validating event (make sure CausesValidation is true).
Another option would be to create a MaskedTextBox and place it so it covers the text box portion of the drop down menu. You would then need to wire up the events so the two form controls remained synced.
You could also look into the ErrorProvider class.
There are a couple of other ways (like a timer which runs ever .3 seconds), but those are usually performance hogs or difficult to maintain.
Update for regular expression comment:
If I was to do this I might use a regular expression or I might manually parse the string.
Either way the KeyUp and Validating events is where I would check the validation of the control. The KeyUp event gives me the option to check as they type while the Validating event allows me to validate when the control loses focus. Which you use will depend on what you want the user experience to be.
If you do not use the KeyUp event to validate, you could add a timer which runs 5 seconds after the last key press. This way the control would not have to lose focus for the error to show.
Update for edited question and comment:
You could not use Format event as your question was on how to format user input, not how things are added to the list. As such that solution does not work with ToolStripComboBox or with ComboBox.
After reading the documentation for ToolStripControlHost, you might be able to cast ToolStripComboBox to ComboBox. If not then you could use the ToolStripControlHost to place the ComboBox onto your form. - This is incorrect or unnecessary, please see update below the quote.
ToolStripControlHost is the abstract base class for ToolStripComboBox, ToolStripTextBox, and ToolStripProgressBar. ToolStripControlHost can host other controls, including custom controls, in two ways:
Construct a ToolStripControlHost with a class that derives from Control. To fully access the hosted control and properties, you must cast the Control property back to the actual class it represents.
Extend ToolStripControlHost, and in the inherited class's default constructor, call the base class constructor passing a class that derives from Control. This option lets you wrap common control methods and properties for easy access in a ToolStrip.
Use the ToolStripControlHost class to host your customized controls or any other Windows Forms control.
To customize a ToolStripItem, derive from ToolStripControlHost and create a custom implementation. You can override methods such as OnSubscribeControlEvents to handle events raised by the hosted controls, and you can put custom functionality into properties to enhance the hosted control.
Update:
According to the ToolStripComboBox documentation you can access the underlying ComboBox through ToolStripComboBox's ComboBox property.
This is why I usually read the documentation on a control before I use it. I might not understand it, but at least I will have an idea what to look for. :)

You should create Format event like this:
private void comboBox1_Format(object sender, ListControlConvertEventArgs e)
{
e.Value = GetFullIpFormat((string)e.Value);
}
And here is code for formating values:
string GetFullIpFormat(string value)
{
string[] ip = new string[4];
for (int i = 0; i < ip.Length; i++)
{
ip[i] = GetIpPart(i, value);
}
return string.Format("{0:###}.{1:###}.{2:###}.{3:###}", ip[0], ip[1], ip[2], ip[3]);
}
string GetIpPart(int partNumber, string ip)
{
string result = "000";
int iLen = 3;
ip = ip.Replace(".", "");
int iStart = partNumber * iLen;
if (ip.Length > iStart)
{
result = ip.Substring(iStart);
if (result.Length > iLen)
{
result = result.Substring(0, iLen);
}
}
return result;
}
This will do formating for you.
Alternativly you can check input on same event for numbers.
This will do the job for you, happy coding! :)

ASP.NET - How to check if one or more field values have been changed

I have a web form where I register a new employee. There're 3 parts in the form: Personal info, Address info, Special Status. But there's only one button for the whole form. When I submit the form all the information is updated to the database. So three Update statements are executed against the database. The methods are UpdatePersonalInfo, UpdateAddressInfo and UpdateSpStatus. Is there a way to check if there's been a change in any field in the certain part and run update method only if it's true. So something like this:
if (There's been any change to the personal data of the employee)
{
UpdatePersonalInfo;
}
if (There's been any change to the address information of the employee)
{
UpdateAddressInfo;
}
Sure I know, I can save all the previous values in a session object in PageLoad and then compare them one by one before running the method. But I thought maybe there's a magic way of doing this more easily.

Not sure that this is a better solution than any of the alternatives you already mentioned, but you could create a default handler to attach to the TextChanged, SelectedIndexChanged, etc events of your controls to keep track of which ones have changed.
List ChangedControls = new List(Of, String);
private void ChangedValue(object sender, System.EventArgs e) {
WebControl cntrl = (WebControl) sender;
ChangedControls.Add(cntrl.ID);
}
Then on your button click scour the ChangedControls list for the relevant controls.