CODEWITHSUNDEEP
c#wpfxamldata-bindingbinding
Rokujolady
Rokujolady

Reputation: 1009

Binding to a property within an instance

I'm working on a project that is getting data from a backend, ie, the data is constantly changing dynamically, and the frontend shouldn't have to care. I need to expose this data to wpf such that someone can bind things to the data in wpf via expression blend. Readonly is fine. In short, how do I do databinding to the property Foostring in a instance of a class "foo" of type "Foo" if my flow of control is roughly the following:

 public partial class Window1 : window
 {
      public Window1()
      {
           InitializeComponent();
           Foo foo = new foo;
      }
   // my text box is defined in the xaml of this window.

 }

public ref class Foo
{
     Foo()
    {
         FooProperty = "work,dammit";
    }
    private string _foostring="";
    public string FooProperty
    {
       get {return _foostring;}
        set {foostring=value;} 

    }
}

I can get things to work if in the constructor of the Foo class I set binding on the text box, and if I inherit from INotifyPropertyChanged and raise an event on the setting of FooProperty. However, this does not expose this variable to expression blend--it's not really setting a datasource. I've tried to set the binding in xaml and it compiles but doesn't update. Any help would be greatly appreciated!

Upvotes: 1

Views: 2725

Answers (1)

brunnerh
brunnerh

Reputation: 185300

[Answer by Rokujolady]
For posterity, I've posted the solution: I was instancing the object foo from c# when I should have been instancing from xaml, because xaml was creating its own instance which was not being updated because I was updating the c# instantiated instance. Apparently you can't reference an object created in c# from xaml, but you can reference one created in xaml from c#. The code ended up like this: XAML:

<Window.Resources>
<local:Foo x:Name "foo" x:Key="FooDataSource" d:IsDataSource="True"/>
...
</Window.Resources>
<Grid x:name="blah">
<Grid DataContext="{Binding Source={StaticResource FooDataSource}}">
<TextBlock x:Name="myText" Text="{Binding FooProperty, Mode=Default}"></TextBlock></Grid>

C# Code looked like this:

public partial class Window1:window
{
     Foo myFooVariable = null;
     public Window1()
     {
          InitializeComponent();
          myFooVariable = this.Resources["FooDataSource"] as Foo;
          myFooVariable.FooString = "Work, Dammit";
     }
}

Upvotes: 1

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