I have a custom usercontrol and I want to do something relatively simple.
When ever a numeric up down in that usercontrol's value changes, have the main form update a display window.
This is not a problem if the NUD was not in a usercontrol but I can't seem to figure out how to have the event handled by the mainform and not the usercontrol.
You need to create an event handler for the user control that is raised when an event from within the user control is fired. This will allow you to bubble the event up the chain so you can handle the event from the form.
When clicking Button1 on the UserControl, i'll fire Button1_Click which triggers UserControl_ButtonClick on the form:
User control:
[Browsable(true)] [Category("Action")]
[Description("Invoked when user clicks button")]
public event EventHandler ButtonClick;
protected void Button1_Click(object sender, EventArgs e)
{
//bubble the event up to the parent
if (this.ButtonClick!= null)
this.ButtonClick(this, e);
}
Form:
UserControl1.ButtonClick += new EventHandler(UserControl_ButtonClick);
protected void UserControl_ButtonClick(object sender, EventArgs e)
{
//handle the event
}
Notes:
Newer Visual Studio versions suggest that instead of if (this.ButtonClick!= null) this.ButtonClick(this, e); you can use ButtonClick?.Invoke(this, e);, which does essentially the same, but is shorter.
The Browsable attribute makes the event visible in Visual Studio's designer (events view), Category shows it in the "Action" category, and Description provides a description for it. You can omit these attributes completely, but making it available to the designer it is much more comfortable, since VS handles it for you.
Try mapping it. Try placing this code in your UserControl:
public event EventHandler ValueChanged {
add { numericUpDown1.ValueChanged += value; }
remove { numericUpDown1.ValueChanged -= value; }
}
then your UserControl will have the ValueChanged event you normally see with the NumericUpDown control.
you can do like this.....the below example shows text box(user control) value changed
// Declare a delegate
public delegate void ValueChangedEventHandler(object sender, ValueChangedEventArgs e);
public partial class SampleUserControl : TextBox
{
public SampleUserControl()
{
InitializeComponent();
}
// Declare an event
public event ValueChangedEventHandler ValueChanged;
protected virtual void OnValueChanged(ValueChangedEventArgs e)
{
if (ValueChanged != null)
ValueChanged(this,e);
}
private void SampleUserControl_TextChanged(object sender, EventArgs e)
{
TextBox tb = (TextBox)sender;
int value;
if (!int.TryParse(tb.Text, out value))
value = 0;
// Raise the event
OnValueChanged( new ValueChangedEventArgs(value));
}
}
one of the easy way to do that is use landa function without any problem like
userControl_Material1.simpleButton4.Click += (s, ee) =>
{
Save_mat(mat_global);
};
For those looking to do this in VB, here's how I got mine to work with a checkbox.
Background: I was trying to make my own checkbox that is a slider/switch control. I've only included the relevant code for this question.
In User control MyCheckbox.ascx
<asp:CheckBox ID="checkbox" runat="server" AutoPostBack="true" />
In User control MyCheckbox.ascx.vb
Create an EventHandler (OnCheckChanged). When an event fires on the control (ID="checkbox") inside your usercontrol (MyCheckBox.ascx), then fire your EventHandler (OnCheckChanged).
Public Event OnCheckChanged As EventHandler
Private Sub checkbox_CheckedChanged(sender As Object, e As EventArgs) Handles checkbox.CheckedChanged
RaiseEvent OnCheckChanged(Me, e)
End Sub
In Page MyPage.aspx
<uc:MyCheckbox runat="server" ID="myCheck" OnCheckChanged="myCheck_CheckChanged" />
Note: myCheck_CheckChanged didn't fire until I added the Handles clause below
In Page MyPage.aspx.vb
Protected Sub myCheck_CheckChanged (sender As Object, e As EventArgs) Handles scTransparentVoting.OnCheckChanged
'Do some page logic here
End Sub
Related
I've got a user control that represents an employee. The xaml is an image of a character icon and there is a textbox for the employee name.
When text is typed into the textbox the Textchanged event is raised and this event handler is called:
private void employeeNameChangedEventHandler(object sender, TextChangedEventArgs args)
{
_employeeName = employeeName.Text;
}
The is a property in the user control so the name can be retrieved:
public string EmployeeName
{
get { return _employeeName; }
}
In MainWindow.xaml.cs I want to listen to the TextChanged eventhandler in the user control.
I've read up about delegates and have a bit of experience with events from Unity but just not sure the best way to implement this in wpf.
Ta
You can use customer routed event.
In your Usercontrol, you need add your routed event, like this:
public static readonly RoutedEvent NameChangedEvent = EventManager.RegisterRoutedEvent
("NameChanged", RoutingStrategy.Bubble, typeof(EventHandler<RoutedEventArgs>), typeof(UserControl1));
public event RoutedEventHandler NameChanged
{
add { this.AddHandler(NameChangedEvent, value); }
remove { this.RemoveHandler(NameChangedEvent, value); }
}
And In your textchanged event of textbox, you should raise your customer routed event.
private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
this.RaiseEvent(new RoutedEventArgs(UserControl1.NameChangedEvent));
}
Now you just need add subscribe your customer routed event where you need your usercontrol as you do use textchanged.
<local:UserControl1 x:Name="uc" NameChanged="NameChanged"/>
And the NameChanged is like this
private void NameChanged(object sender, RoutedEventArgs e)
{
//when you input one character in you usercontrol, you will get here
}
I have created custom control. I would like to perform in my custom control after that Form.Shown event. I have tried in Control.GotFocus event which has triggered before that Form.Shown event. I want to make the changes in my control after that Form.Shown event.
Is it possible? If yes means, please suggest me how to do this?
Thanks,
You could register to the event:
public class MyControl : UserControl
{
// you need a reference to the hosting Form
public MyControl(Form frmHost)
{
frmHost.Shown += FormHost_Shown;
}
private void FormHost_Shown(object sender, EventArgs e)
{
// Do your work
}
}
When you the create an instance of your control, just pass a reference to the hosting form:
this.Controls.Add(new MyControl(this));
If you need a parameterless constructor you could make the hosting Form a property of your control and set that property before the Shown event happens:
public class MyControl : UserControl
{
private Form frmHost;
public Form FrmHost
{
get
{
return frmHost;
}
set
{
frmHost = value;
frmHost.Shown += FormHost_Shown;
}
}
private void FormHost_Shown(object sender, EventArgs e)
{
// Do your work
}
}
public class MyForm : Form
{
public MyForm()
{
InitializeComponent();
// User control was created elsewhere (perhaps in the designer)
myUserControl.FrmHost = this;
}
}
No, the documented order of events when activating for the first time a windows forms is the following:
Control.HandleCreated
Control.BindingContextChanged
Form.Load
Control.VisibleChanged
Form.Activated
Form.Shown
As you can see, Shown is the last fired event. You would need to implement your own event in your custom base Form:
public event EventHandler AfterShwon;
protected override void OnShown(EventArgs e)
{
base.OnShow(e);
OnAfterShown(e);
}
protected virtual void OnAfterShown(e)
{
AfterShwon?.Invoke(this, e);
}
I've created a custom UserControl, it's a button with a grid inside it.
From the Page that contains it, MainPage.xaml, I need to bind a Click event to the UserControl, and the function for the EventHandler must be written outside, in the MainPage (not inside the UserControl).
So, reading through this question, I've created an Event and a EventHandler function that triggers the event. These are inside the UserControl.
This are the classes
UserControl.xaml.cs
public class MyButton : UserControl
{
public event RoutedEventHandler ButtonClicked;
private void ButtonClickedHandler()
{
//Null check makes sure the main page is attached to the event
if (this.ButtonClicked != null)
this.ButtonClicked(this, new RoutedEventArgs());
Debug.WriteLine("ButtonClickedHandler");
}
}
MainPage.xaml.cs
private void MyButton_Click(object sender, RoutedEventArgs e)
{
Debug.WriteLine("MyButton_Click");
}
private void MyButton_Loaded(object sender, RoutedEventArgs e)
{
(sender as MyButton).ButtonClicked += MyButton_Click;
}
As you can see, I've placed a couple of Debug.WriteLine, but they don't get triggered, and I don't know what I'm doing wrong.
Just having a single method in your code that is never called by anything will not make your program work. You will first have to call the ButtonClickedHandler() method each time your button is clicked.
To do that, just register a method for the click-event of your button in your xaml file.
<Button Content="This Is Your Button" Click="YourButtonClick"/>
And then call the ButtonClickedHandler() method in there:
private void YourButtonClick(object sender, RoutedEventArgs e) {
ButtonClickedHandler();
}
A simpler way to solve the problem is using an event property:
UserControl.xaml.cs
public Event RoutedEventHandler ButtonClicked
{
add {
ButtonName.Click += value; //use the name of your button here
}
remove {
ButtonName.Click -= value;
}
}
And then you can simply register to that event in your MainWindow:
private void MyButton_Loaded(object sender, RoutedEventArgs e)
{
(sender as MyButton).ButtonClicked += MyButton_Click;
}
By the way, I think it is better to register the event in the xaml file where you also create the control:
I am really new to programming and currently working on a C# Windows Forms application.
The problem is the following:
I have a Form with different objects and controls like: tabpages, textboxes, timers, etc .
I also have a UserControl form which I load into one of the main Form's tabpages.
I would like to write a code into the UserControl , how can I manipulate element properties of the main Form.
For example: when I click on a button on the UserControl form It sets the main Form's timer.Enabled control to true.
It is possible to do this, but having the user control access and manipulate the form isn't the cleanest way - it would be better to have the user control raise an event and have the hosting form deal with the event. (e.g. on handling the button click, the form could enable/disable the timer, etc.)
That way you could use the user control in different ways for different forms if need be; and it makes it more obvious what is going on.
Update:
Within your user control, you can declare an event - In the button click, you raise the event:
namespace WindowsFormsApplication1
{
public partial class UserControl1 : UserControl
{
public event EventHandler OnButtonClicked;
public UserControl1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
EventHandler handler = OnButtonClicked;
// if something is listening for this event, let let them know it has occurred
if (handler != null)
{
handler(this, new EventArgs());
}
}
}
}
Then within your form, add the user control. You can then hook into the event:
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
userControl11.OnButtonClicked += userControl11_OnButtonClicked;
}
void userControl11_OnButtonClicked(object sender, EventArgs e)
{
MessageBox.Show("got here");
}
}
}
You may want to rethink what it is you are trying to accomplish. However, to answer your question, it can be done.
The best way to do it is to make a property in your UserControl called MainForm:
public Control MainForm {
get;
set;
}
Then, in your MainForm's Load event, set the property to itself:
userControl1.MainForm = this;
Finally, in your user control, set the MainForm's timer:
protected button_click(object sender, EventArgs e)
{
timerName = "timer1";
EnableTimer(timerName);
}
private void EnableTimer(timerName)
{
var timer = MainForm.Controls.FirstOrDefault(z => z.Name.ToLower().Equals(timerName.ToLower());
if (timer != null)
{
((Timer)timer).Enabled = true;
} else {
// Timer was not found
}
}
This is very simple. It's called events. On the user control you would expose an event with a EventHandler for the form to subscribe to.
public partial class MyUserControl : UserControl
{
/// You can name the event anything you want.
public event EventHandler ButtonSelected;
/// This bubbles the button selected event up to the form.
private void Button1_Clicked(object sender, EventArgs e)
{
if (this.ButtonSelected != null)
{
// You could pass your own custom arguments back to the form here.
this.ButtonSelected(this, e)
}
}
}
Now that we have the user control code we'll implement it in the form code. Probably in the constructor of the form you'll have some code like below.
MyUserControl ctrl = new MyUserControl();
ctrl.ButtonSelected += this.ButtonSelected_OnClick;
Finally in the form code you'll have a method that subscribed to the event like the below code that will set the Timer enabled to true.
private void ButtonSelected_OnClick(object sender, EventArgs e)
{
this.Timer1.Enabled = true;
}
And that's how you allow an event on a user control on a form set an object on the form.
You can set the timer1.Modifiers property to "internal" and access it with an instance to Form1:
form1.timer1.Enabled = true;
You need to have an instance of your class Form1, not the class itself. For example:
// INVALID
Form1.timer1.Enabled = true;
// VALID
var form1 = Form1.ActiveForm;
form1.timer1.Enabled = true;
But this is not a very clean way to do this, you would rather use events as described in NDJ's answer.
You need to put the below code,
(`userControl11.OnButtonClicked += userControl11_OnButtonClicked;`)
in a separate file in Visual Studio. The other file is called 'Form1.Designer.cs', and can be found in the Solution Explorer pane under
Form1 >> Form1.cs >> Form1.Designer.cs.
Hope this helps!
I want to get the clicked event of a Button which is in my UserControl and I am adding that UserControl dynamically in my form. I want the event to be raised in the Form in which i am adding the UserControl. Please if anyone could suggest me proper way then it will be really very helpful.
You need to expose the event in your user control, then subscribe it when you add the user control to the form. e.g.:
public partial MyUserControl:Control
{
public event EventHandler ButtonClicked;
private void myButtonClick(object sender, EventArgs e)
{
if (this.ButtonClicked != null)
this.ButtonClicked(this, EventArgs.Empty);
}
}
public partial MyForm:Form
{
private void MethodWhereYouAddTheUserControl()
{
var myUC = new MyUserControl();
myUC += myUC_ButtonClicked;
// code where you add myUC to the form...
}
void myUC_ButtonClicked(object sender, EventArgs e)
{
// called when the button is clicked
}
}
I guess you're using Winforms referring to your title.
What you can do it to forward your Click event.
So in the ctor of your UserControl
public class MyUserControl
{
public event EventHandler MyClick;
private void OnMyClick()
{
if (this.MyClick != null)
this.MyClick(this, EventArgs.Empty);
}
public MyUserControl()
{
this.Click += (sender, e) => this.OnMyClick();
}
}
Add your own event to your custom user control.
Inside your customer user control, once you add the button, also attach your (internal) event handler that will then raise your own public event with some way to tell the event handler which button has been clicked (you'll most likely need your own delegate here).
Once that's done, your form can add its own event handler just like you add one to the standard controls.
Rereading your question, this might not be the exact structure (the button is fixed, but the user control is dynamically added?). In any way, it should be almost the same, it just differs where/when you add the event handler upon creation.
With one static button it's a lot easier to be done - assuming you're using Windows Forms:
In your custom user control:
public event EventHandler ButtonClicked; // this could be named differently obviously
...
public void Button_OnClick(object sender, EventArgs e) // this is the standard "on button click" event handler created using the form editor
{
if (ButtonClicked != null)
ButtonClicked(this, EventArgs.Empty);
}
In your form:
// create a new user control and add the event
MyControl ctl = new MyControl();
Controls.Add(ctl);
ctl.ButtonClicked += new EventHandler(Form_OnUserControlButtonClicked); // name of the event handler in your form that's called once you click the button
...
private void Form_OnUserControlbuttonClicked(object sender EventArgs e)
{
// do whatever should happen once you click the button
}
when you are adding your usercontrol to your form, register the click event (if it is public) usercontrol.button.Click += new EventHandler(usercontrolButton_Click);
register the button's Click event within your usercontrol