Binding String property to TextBox Text from Code Behind

Question

Sorry for this basic question

I have a data model :

class data_test
    {
        public string textdata { get; set; }
        public bool booldata { get; set; }
        public bool checkdata { get; set; }
        public data_opt enumdata { get; set; }
    }

Here's Enum :

   enum data_opt
        {
            managed = 1,
            unmanaged = 2 ,
            mixed = 3
        }

Then I create a data model :

    var n_Data = new data_test()
    { textdata = "test data",
    booldata = false,
    checkdata = true ,
    enumdata = data_opt.mixed
    };

And I create a text box from code behind :

 var text_box = new TextBox();

Now I want to bind text_box.Text property to n_Data.textdata from code behind

The same way DataGrid works , two-way connection with real-time update.

I found some pages :

Binding String Property in Code-Behind TextBlock

WPF Data Binding to a string property

Binding string property to object

Unfortunately , none of them worked for me , Here's my code to bind:

Binding binding = new Binding();
binding.Path = new PropertyPath("textdata");
binding.Source = n_Data;
text_box.SetBinding(TextBlock.TextProperty, binding);

Also I tried this :

    Binding binding = new Binding();
    binding.Path = new PropertyPath("textdata");
    binding.Source = n_Data;
    BindingOperations.SetBinding(text_box, TextBlock.TextProperty, binding);

Both of them don't work , What am I doing wrong ?

You have not set datacontext to your viewmodel. You also haven't implemented inotifyprooertychanged, which you should do EVEN if you don't want to change data in the vm and see the view respond. — Andy, Mar 16 '19 at 18:01
It's not necessary to set the DataContext when you explicitly set the Binding's Source. And of course you only have to implement INotifyPropertyChanged when your logic actually requires a property change notification. — Clemens, Mar 16 '19 at 18:03
@Andy As I know there's no need to `INotifyPropertyChanged ` and `DataContext ` for single binding ... I did what **Fruchtzwerg** said and it's working fine now... — , Mar 16 '19 at 20:10
@Clemens , It's working fine , Do I really need `INotifyPropertyChanged` ??? I change value and GUI change and I change GUI and value change , Why I need `INotifyPropertyChanged` ? — , Mar 16 '19 at 20:11
As said, you do of course not need to implement when it is not required. — Clemens, Mar 16 '19 at 20:16
Unless it's been fixed in very recent framework versions, you can get a memory leak binding to properties in a plain class that doesn't implement inpc. — Andy, Mar 16 '19 at 20:21
@Clemens I just checked when I create element by code , text box updates value of property but when I change value from code , text box will not update... Do you have any good link about `INotifyPropertyChanged ` ? — , Mar 16 '19 at 20:22

score 0 · Accepted Answer · edited Mar 16 '19 at 22:07

0

Since your target is a TextBox, you can't use TextBlock.TextProperty as property to bind. You need to use TextBox.TextProperty:

text_box.SetBinding(TextBox.TextProperty, binding);

edited Mar 16 '19 at 22:07

Wai Ha Lee

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answered Mar 16 '19 at 17:57

Fruchtzwerg

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Binding String property to TextBox Text from Code Behind

1 Answers1