Hai
am having a WPF user control in my WPF Form, when i click my button in my form , i just want to pass some value to the textbox which is in the usercontrol, tell me how to do this.
There are several ways you can do this. The easiest way is to use a String property and implement INotifyPropertyChanged in your UserControl.
To illustrate, you will have your UserControl like so:
/// <summary>
/// Interaction logic for TextBoxUsercontrol.xaml
/// </summary>
public partial class TextBoxUsercontrol : UserControl, INotifyPropertyChanged
{
private string _text;
public string Text
{
get { return _text; }
set
{
_text = value;
if(PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs("Text"));
}
}
public TextBoxUsercontrol()
{
DataContext = this;
InitializeComponent();
}
public event PropertyChangedEventHandler PropertyChanged;
}
Now the TextBox in your UserControl must bind itself to your Text property like so:
<TextBox Text="{Binding Text}" />
Then in your WPF form, you will have your UserControl declared and a button to handle the click like so:
<local:TextBoxUsercontrol x:Name="textBox" />
<Button Click="ButtonBase_OnClick" >Add Text</Button>
And finally, in your Click handler:
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
textBox.Text = "Hello!";
}
Having shown you the solution, I give your question asking skill a 1 out of 5. You can be a lot more specific with your question and give sample codes snippets as I have done without asking us to download your whole solution from a site that we must wait download it (not to mention most of us are security conscious about downloading unknown files).
Good luck.
Standard WPF? NO WAY.
Why? You dont pass values around. You get a click event on the item that is clicked (the button) with elements defined on the button (only), then in the code you access the other elements, which thus also have to be either defined in code (the standard way) and expose their values through something called "properties", OR you get the control by name and extract the value. But you dont pass any additional data around.
Look at the tutorials ;)
If you want to PASS values around to METHODS on a click, you need to use something like caliburn (http://www.codeplex.com/caliburn) which allows you to map the click to a method and grab the values passed into the method from other controls.
Just Create a Dependency property and Bind the Porperty to the UserControl's TextBox. While creating the object itself assign the value to the Usercontrol's dependency property.
Related
I apologize if the question title isn't really specific, I'm not exactly sure how to condense the problem I'm having down to a few words. But to simplifiy the problem I'm having, here is my issue:
I'm creating a tool using WPF that consists of a TextBox that will contain a path to a directory and a Button that will allow you to Browse to a certain directory. Now, when I select the Browse button, it pops up a dialog, allows the user to select a directory and then I have some methods that will disable some buttons and updates some Brushes on the screen if the path doesn't meet a certain set of criteria. No problems there, got that working.
My problem is the TextBox that this Browse button correlates with. This TextBox is using a binding as such:
In my MainWindow.xaml (Yes, this is the simplified, focused version):
<Window>
<TextBox Text="{Binding Directory}" TextChanged="Directory_TextChanged" />
<Button Content="Browse..." Click="Browse_Click"/>
</Window>
In my code MainWindow.xaml.cs file:
public partial class MainWindow: Window
{
private ViewModel myViewModel;
public MainWindow()
{
myViewModel = new ViewModel();
this.DataContext = myViewModel;
}
private void Browse_Click(object sender, RoutedEventArgs e)
{
// Dialog stuff that's working
viewModel.Directory = dialog.SelectedPath;
}
private void InstallDir_TextChanged(object sender, TextChangedEventArgs e)
{
ValidatePath(); /* Disables/enables buttons and updates brushes based on validation. Also working */
}
private void ValidatePath() {/* */}
}
Like I mentioned earlier, the browse button works fine. I'm trying to figure out however, how I can get this to work if I type a directory alongside it. Because if I type something in the textbox, that would mean that inside of the InstallDir_TextChanged() function I would have to set viewModel.Directory, but since I have the INotifyPropertyChanged attached to this ViewModel, this function would get called recursively.
I tried doing the validation stuff within the viewmodel, but I couldn't figure out how to update the brushes/buttons in MainWindow if I did this. (Still relatively new to C# so I haven't learned the ins and outs yet. This is the first WPF tool I've been making from scratch, so just a disclaimer).
Would anyone have any ideas (or logic) I can approach to try and accomplish this? If there's any further clarification needed, that's not an issue. I don't need an exact definitive answer. Maybe some advice that could point me in the correct direction would definitely suffice. I don't have a problem trying to figure stuff out.
I have written a property in a user control class using set get like this :
public partial class MyUserControl : UserControl
{
public string ServerName { get; set; }
public PagingUserControl()
{
InitializeComponent();
}
}
then by adding this user control to a windows form project I set ServerName in the "Misc" section of properties window.
now here is the question, how can I access ServerName from another usercontrol ? I think I should access the property "ServerName" of the object made by the constructor of "MyUserControl"
The right approach is to reverse the data flow by extracting your model being the value of the ServerName property out of the user control and bind both user controls to it, see Windows Forms Data Binding for details. This way you can save a lot of time on plumbing and passing data between your components.
If you are specifically looking for how to implement this with your existing code then following steps below may be able to help you too. Once you drop an instance of the user control to the form, the designer is going to generate some code for it in the Form1.Designer.cs file.
// the declaration of your user control
private MyUserControl1 myUserControl11;
private void InitializeComponent()
{
// the initialization of your user control
this.myUserControl11 = new WindowsFormsApp3.MyUserControl1();
}
This code makes it possible to access the instance of the user control from the form. If you are asking how to share the value of this property with another control you would need to implement INotifyPropertyChanged inside your user control.
public partial class MyUserControl1 : UserControl, INotifyPropertyChanged
And then subscribe your parent form to this event.
private void InitializeComponent()
{
// subscribe to the user control event
this.myUserControl11.PropertyChanged +=
new System.ComponentModel.PropertyChangedEventHandler(
this.myUserControl11_PropertyChanged);
}
// handle the event by updating the other control
private void myUserControl11_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
textBox1.Text = myUserControl11.ServerName;
}
Once you have notification implemented you may consider looking at how data binding can be used to achieve the data propagation between controls with less code. Hope it helps!
I'm new to WPF and MVVM and am going through an example on Microsoft's site, however, I don't see how the binding is done. In the example linked, there's this piece of code:
public partial class MainPage : UserControl
{
private PartInventoryViewModel viewModel;
public MainPage()
{
InitializeComponent();
viewModel = new PartInventoryViewModel();
this.DataContext = viewModel;
}
private void PartSearchButton_Click(object sender, RoutedEventArgs e)
{
viewModel.GetParts();
}
}
Apparently:
It notifies the ViewModel instance when the user clicks the PartSearchButton.
But how? There's no binding in the XAML above for the PartSearchButton in the example. Is it a normative that if you name your function YourButtonName_Clicked() it will trigger when the button is clicked? Or does it become a listener if you create the function with the (object sender, RoutedEventArgs e) arguments? Or is there some XAML which this tutorial is not showing, where the binding occurs?
Thank you for your answer, sorry if it's a newb one.
Microsoft is not showing all the code that is necessary here. Basically all that this code does is setting the DataContext to a newly instantiated ViewModel. The PartSearchButton_Click is a simple Click-Event-Handler that should look something like this in your XAML-file:
<Button Click="PartSearchButton_Click">Search</Button>
The whole binding thing is happening in these 2 lines of the datagrid in your xaml file:
ItemsSource="{Binding Parts}"
SelectedItem="{Binding CurrentPart, Mode=TwoWay}"
This is telling the DataGrid that it should look for a public property called Parts in the current DataContext. You set the DataContext to a new instance of PartInventoryViewModel, so there needs to be a public property Parts somewhere in there. I guess the PartInventoryViewModel class will be explained a bit further down on the Microsofts site.
The XAML snippets from your link are effectively missing that event handler.
The <source>_<event> guideline is the convention for naming event handlers, but by no means the function gets automatically bound to the corresponding event; you have to add the handler either programmatically or in XAML.
That said, associating application logic to buttons is usually done in WPF by means of commands instead of event handlers. The view model exposes a property of type ICommand, anf the view binds the Command dependency property of a Button (or other controls) to it. How that command is implemented under the hood is completely irrelevant to the view.
What I want is to store a method with parameters owned by one class in a variable in another class for later execution. The first class would be my MainWindow class and second is a UserControl. The method I want to pass would stand in as a SelectionChanged event for a ListBox contained in the UserControl. The method would require a parameter only the UserControl will know at the time items are changing.
An example for my method (in MainWindow) would be as follows:
public void MethodToPass(string UniqueParameterValue) {
//...do stuff with special string
}
And I would pass the method in my MainWindow class like:
//In MainWindow.Loaded
this.userControlInstance.SelectionChanged += MethodToPass;
Because I'm not directly assigning it to the ListBox, I would do so in the UserControl like:
private void selectionChanged;
public void SelectionChanged {
get {
...
}
set
{
this.selectionChanged = value;
this.listBox1.SelectionChanged += value;
}
}
I feel like NOT directly setting the ListBox is redundant, but my MainWindow class does not allow me to "see" it. I also feel like the more politically correct way to do this is to store the method in a variable, but I don't know how to do that or call it.
How are operations like this usually done?
You should be able to expose the properties of your user control by creating them as class properties as usual. Then you can create an event on your user control which is raised by the SelectionChanged event of your ListBox. You can subscribe to this event using a delegate on your main window.
Check out these links:
How to access properties of a usercontrol in C#
How do I make an Event in the Usercontrol and Have it Handeled in the Main Form?
i`m trying to design a dialog window which will display different messages depending on what case will be true.
so for example when i have a
<CustomDialog Content="{Binding Path=Name}"/>
is there a possibility to change the Binding Path=Name to Path=Whatever or how do you implement something like that ? When the Control should use other resources on runtime.
--------------edit
I ok i`ll try to describe my problem better ;)
I have an ResourceDictionary with strings for example
<System:String x:Key="Message1">Message1</System:String>
<System:String x:Key="Message2">Message2</System:String>
<System:String x:Key="Message3">Message3</System:String>
So when I now call my UserControl
Doing it customdialog.visibility = true; for example
<CustomDialog Text=”” />
I want to define which key from the resourcedictionary is taken when the dialog popups up.
something like customdialog.text = Message1; but Loaded from the ResourceDictionary
is that possible or is there an better way of doing something like this ?
You may provide another content to the same property Name at runtime in code-behind. Suppose you have Initialize (or may be Show) method in your CustomDialog and the last one implements INotifyPropertyChanged:
public class CustomDialog : INotifyPropertyChanged
{
//Your implementation of class goes here
public void Initialize(string message)
{
Name = message;
Visibility = Visibility.Visible;
}
public string Name
{
get {return _name;}
set
{
if (_name != value)
{
_name = value;
raiseOnPropertyChanged("Name");
}
}
}
//Your implementation of class goes here
}
In method Initialize there will be updated Name property and your control will be shown. When there will be setting of Name property must be raise PropertyChanged event which will tell presentation that binded value has updated and to reflect it in the UI.
The easiest way I can think of would be to bind to the parent item, not to a child property, and then use a DataTemplateSelector to select a different template at run-time, depending on some condition involving the bound object or its properties.
Alternatively, if the Content has well defined types, you only need to define DataTemplates with specific data types, and they will be automatically used to display objects of those types.
Not knowing more about the context I can't be much more specific, but if you search for more information on DataTemplates and DataTemplateSelectors you should be fine - you can find a lot of useful information here.