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How to get ALL child controls of a Windows Forms form of a specific type (Button/Textbox)?
(28 answers)
Closed 2 years ago.
What I am trying to do is to change background color of the button once it's active. So far I achieved it by this way:
private void button3_Click(object sender, EventArgs e) // METEO BUTTON
{
DefaultButtons();
button3.BackColor = Color.LimeGreen;
// REST OF THE CODE HOES HERE
}
While DefaultButtons function is like this:
public void DefaultButtons()
{
List<Button> buttonsToDefualt = new List<Button>()
{
// MAIN MENU
button1,
button2,
[...]
buttonX
};
foreach (var item in buttonsToDefualt)
{
item.BackColor = Color.Green;
}
}
Now swapping buttons works like this: Change entire list to default color, then activated button change color to LimeGreen. It would be fine but:
1) I have to launch DefaultButtons(); for EACH button Click
2) I have to manually add all buttons to list, and now I have more than 120 buttons (Yeah, building custom interface...), and keep adding that by hand is tiring.
I tried this:
void DefaultButtonsNew()
{
foreach (Button b in this.Controls)
{
if (b != null)
{
b.BackColor = Color.Green;
}
}
}
But I've got an Exception: System.InvalidCastException: 'Can't throw object 'System.Windows.Forms.SplitContainer' on type 'System.Windows.Forms.Button'.'
If you're looking for a way to reset all buttons on the form, and some buttons are inside other containers, then we need to recursively loop through each control's Controls collection to find all the buttons.
One easy way to do that is to write a method that takes in a container (like the form), iterates through its Controls collection, changes the BackColor of any Button controls, and calls itself for the other control types:
private void ResetButtons(Control container)
{
// Loop through each control in this container
foreach (Control control in container.Controls)
{
var button = control as Button;
// If the control is a button, change it's backcolor
if (button != null) button.BackColor = Color.Green;
// Otherwise check it's controls collection (recursive call)
else ResetButtons(control);
}
}
Next, it sounds like you're looking for a way to avoid writing out a call to this method, and to change the BackColor of the current button, in every button click event.
One easy way around this is to simply add this method, and the BackColor change, to every button click in code. We can write a method to do this using a similar pattern - loop through every control in every container, and if it's a button, add a method to it's click event:
private void HookupButtonClickEvent(Control container)
{
// Loop through each control in this container
foreach (Control control in container.Controls)
{
var button = control as Button;
// If the control is a button, add a method to it's click event
if (button != null)
{
button.Click += (s, e) =>
{
ResetButtons(container);
button.BackColor = Color.LimeGreen; // Change this button's color
};
}
// Otherwise check it's controls collection (recursive call)
else HookupButtonClickEvent(control);
}
}
Now, all we have to do is call the ResetButtons and HookupButtonClickEvent in our form's constructor, and every button will start with the same backcolor and will have our reset method call in it's click event:
public Form1()
{
InitializeComponent();
HookupButtonClickEvent(this);
ResetButtons(this);
}
Note that this does not prevent you from adding additional click events to the buttons. It merely provides a way to hook up the common functionality to all buttons without writing a bunch of duplicated code.
You can still double-click the controls on your form to add other Click event handlers:
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("Button one clicked - doing something unique here");
}
private void button2_Click(object sender, EventArgs e)
{
MessageBox.Show("Button two clicked - doing something else here");
}
The iterator on Controls collection returns all the controls and trying to cast it to Button should an do fail.
Change your method like this:
void DefaultButtonsNew()
{
foreach (Control b in this.Controls)
{
if (b is Button)
{
b.BackColor = Color.Green;
}
}
}
Related
I have 10 panels all visible = false and have 10 buttons
panels name = p1, p2, p3...etc
buttons name = b1, b2, b3...etc
I wanna when click on button(b1)
make panel(p1) visible = true
relocate and resize panels
The new location and new size for all panels are same,
Can I make a function do the relocate and resize instead of write a code more times like this
private void b1_Click(object sender, EventArgs e)
{
p1.Visible = true;
p1.Location = new System.Drawing.Point(9, 247);
p1.Size = new System.Drawing.Size(1120, 464);
}
You can assign all buttons' click event to the same event handler. The parameter sender is the object that fires the event which in your case it is one of your buttons. Then check the sender's Text or Name property and find which button was clicked. For panels, you could make a method with a Panel type parameter and do what you want.
private void btn_Click(object sender, EventArgs e)
{
// here put code to hide all panels
//...
//then show and relocate the panel related the clicked button as follows
switch ((sender as Button).Name) //or button's Text
{
case "b1":
showPanel(pl);
break;
case"b2":
showPanel(p2);
break;
//other cases
//...
}
}
private void showPanel(Panel pnl)
{
//show and relocate
pnl.Visible = true; //I consider pnl.Show(); as it's more readable
//...
}
Don't forget to hide all panels at the beginning of the click event. You can use following method if you do not have any other panel in your control except those 10 ones.
private void hidePanels()
{
foreach (Control c in yourControl.Controls) //replace yourControl with the control that is the container of your panels e.g. your form
{
if (c is Panel) c.Visible = false; //or c.Hide();
}
}
I haven't tested this code, but it should work.
I am developing an application for a WindowsCE device. Within my application I have five Panels, in which only one of them is visible at time.
Each panel has many different components, however, one of those many components is a button which has an unique Tag property set to btnOK.
Keeping in mind that each Panel has one of those unique buttons, and each of those buttons has a different function:
How can I get my "Enter" KeyPress event to find the Visible OK button and perform a click?
try creating a function:
private Control FindControl(Control parent, string ctlName)
{
foreach(Control ctl in parent.Controls)
{
if(ctl.Name.Equals(ctlName))
{
return ctl;
}
FindControl(ctl, ctlName);
}
return null;
}
use the function like this:
Control ctl = FindControl(this, "btnOK");
if (ctl != null)
{
btnOK_Click(this, new ButtonEventArgs());
}
this assumes your button click event looks like this...
button1_Click(object sender, ButtonEventArgs e)
{
}
I have a Windows form named Form1 and panel within this form named panel1. I use the panel only to place buttons there so that I can group them and work with them separately from the other buttons in my Form1. For the purpose of my program I need to handle every button click made from the buttons inside panel1. For this purpose I use the same code snippet:
public Form1()
{
InitializeComponent();
// Set a click event handler for the button in the panel
foreach (var button in panel1.Controls.OfType<Button>())
{
button.Click += HandleClick;
}
}
What I need to do is to have a way to identify which button exactly has been clicked. For this purpose I played a little bit with my handler method:
private void HandleClick(object o, EventArgs e)
{
MessageBox.Show("HI" + o.ToString());
}
which gave me some hope because I get this:
It's the second part - Text: button4 which is actually enough information to continue with my work. But I can't find a way to get this piece of information without some complicated string manipulations. So is there a way to get this or other unique information about the button been clicked given the way I have written my code?
private void HandleClick(object sender, EventArgs e)
{
var btn = sender as Button;
if (btn != null)
{
MessageBox.Show(btn.Text);
}
}
One option is to cast the object to a Button, but rather than doing the casting you can change how the event handler is assigned so that you don't need to cast in the first place:
foreach (var button in panel1.Controls.OfType<Button>())
{
button.Click += (_,args)=> HandleClick(button, args);
}
Then just change the signature of HandleClick to:
private void HandleClick(Button button, EventArgs e);
You need to cast sender to the Button class so you can access its properties:
Button b = (Button)sender;
MessageBox.Show(b.Text);
I am working on a form that has lots of buttons. When the user clicks one button the background should change color. If they click another button on the form its background should change color and the previous buttons color should return back to the original color.
I can do this by hard coding in every button but this form has alot of buttons. I am sure there has to be a more efficient way of doing this
I have this so far
foreach (Control c in this.Controls)
{
if (c is Button)
{
if (c.Text.Equals("Button 2"))
{
Btn2.BackColor = Color.GreenYellow;
}
else
{
}
}
}
I can get the background for Btn2 to change. How would i change the background for all the other buttons in the form. Any ideas how i could do this without having to hardcode each button.
The code below will work without regard to the number of buttons on the form. Simply set the button_Click method to be the event handler of all buttons. When you click on a button, its background will change color. When you click on any other button, that button's background will change color, and the previously-colored button's background will revert to the default background color.
// Stores the previously-colored button, if any
private Button lastButton = null;
...
// The event handler for all button's who should have color-changing functionality
private void button_Click(object sender, EventArgs e)
{
// Change the background color of the button that was clicked
Button current = (Button)sender;
current.BackColor = Color.GreenYellow;
// Revert the background color of the previously-colored button, if any
if (lastButton != null)
lastButton.BackColor = SystemColors.Control;
// Update the previously-colored button
lastButton = current;
}
This will work as long as you don't have any control containers (eg Panels)
foreach (Control c in this.Controls)
{
Button btn = c as Button;
if (btn != null) // if c is another type, btn will be null
{
if (btn.Text.Equals("Button 2"))
{
btn.BackColor = Color.GreenYellow;
}
else
{
btn.BackColor = Color.PreviousColor;
}
}
}
if your buttons are inside of a panel do the code below, in foreach
you will get all the buttons inside of pnl2Buttons panel and then try to pass the text name of the button that you want to change the background
and the rest will have a SeaGreen color.
foreach (Button oButton in pnl2Buttons.Controls.OfType<Button>())
{
if (oButton.Text == clickedButton)
{
oButton.BackColor = Color.DodgerBlue;
}
else
{
oButton.BackColor = Color.SeaGreen;
}
}
Elaborating on the answer from #Brett Wolfington in 2013...
You can use a simple method to reduce the code in the mouse button_Click events methods.
Below I use the method Chgcolor and invoke it via a one liner in my button_Click events. It helps to reduce the redundancy and by calling current.BackColor = Color.GreenYellow; after all the checks I can now click on 1 button repeatedly without the color disappearing.
Example below from Visual Studio community 2022
private Button? lastButton = null;
private void Chgcolor(Button current)
{
if (lastButton != null)
{
lastButton.BackColor = SystemColors.Control;
}
lastButton = current;
current.BackColor = Color.GreenYellow;
}
private void Button_Click(object sender, EventArgs e)
{
Chgcolor((Button)sender);//call the check color method
}
private void Button2_Click(object sender, EventArgs e)
{
Chgcolor((Button)sender);//call the check color method
}
I want to use a wheel to change (for example) 30 buttons' background image each time a form loads.
I cannot use this:
for(int i=1;i<=30;i++)
{
button i .backgroundimage=image.fromfile("URL");
}
What should I do?
There are many possible interpretations of your problem. Why can't you use your code? There are also different solutions for your problem.
As example:
public Form1() // Constructor
{
InitializeComponent(); // Ensure all controls are created.
List<Button> buttons = new List<Button>(30);
buttons.Add(mybutton1)
buttons.Add(mybutton2)
// Go futher with all your buttons.
}
private void Form1_Load(object sender, System.EventArgs e) // Create a load event
{
foreach(Button button in buttons)
{
button.BackgroundImage = Image.FromFile(path);
// Note: The file remains locked until the Image is disposed!
}
}
Well you could use something like this assuming this code executes in a Form_Load and the buttons Parent control is your form. Have in mind that you should supply the real path to your image that you want to set as a background image
string path = "rootNameOfTheImage";
int counter = 0;
foreach(Control ctrl in this.Controls)
{
if(ctrl is Button)
{
Button btn = (Button)ctrl;
if(/* test if this button should be used */)
{
btn.BackgroundImage=Image.FromFile(path + counter++.ToString() + ".jpg");
}
}
}