How to set this event programmatically?

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I want to set the TextBoxBase.TextChanged of a ComboBox via code. In other words, I want to do the following:

XML

<Combobox Textboxbase.Textchanged="comboBox1_TextChanged" />

...but outside of XAML (in C# code).
Can someone help me? I've tried some things and searched the web but I had no luck. I haven't delved in to WPF so such yet...

Perhaps I must do sth with System.Windows.Controls.Primitives.TextBoxBase.TextChangedEvent but I have no idea what and how...

I have found that I could access the inner TextBox of the ComboBox like that:

C#

protected override void OnRender(System.Windows.Media.DrawingContext drawingContext)
{
        base.OnRender(drawingContext);
        TextBox txt = this.GetTemplateChild("PART_EditableTextBox") as TextBox;
        txt.TextChanged += new TextChangedEventHandler(txt_TextChanged);
}

...to set the event there, but isn't there an easier/better/reliable way?

Posted 1-Nov-12 22:28pm

KEL3

Updated 1-Nov-12 22:52pm

v9

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YvesDaoust 2-Nov-12 5:52am

Doesn't it work if you just assign a value to the Text property and handle the TextChanged event of the Combo ?

KEL3 2-Nov-12 6:08am

Unfortunately not.
This is mostly a problem for ComboBoxes with the IsEditable property set to true.
There is a problem with ComboBox and when the event handler for TextChanged gets called (when you edit the text contents of it by typing inside it) you cannot see the new Text value (you see the value before modification).

This is a related discussion:
http://social.msdn.microsoft.com/Forums/en/wpf/thread/bf7de95a-b088-48e9-989f-d5f9e3a857da

Textboxbase.Textchanged solves a lot of problems, but I have problems accessing it by code...

YvesDaoust 2-Nov-12 6:13am

What is the real issue then, that you can't raise the event or that you can't get the changed content ?

KEL3 2-Nov-12 6:27am

Oups! My bad!
I CAN get the new value (I just do (e.OriginalSource as TextBox).Text). Forget what I said before.
The problem is how to set the event handler by code.
There doesn't seem to be any comboBox1.TextChanged.

YvesDaoust 2-Nov-12 9:45am

You are right. I was referring to the Windows Forms combo. In WPF, you will use property comboBox1.TextBox.Text and event comboBox1.TextBox.TextChanged

KEL3 2-Nov-12 10:11am

I don't see a any "comboBox1.TextBox" either. That's the problem.
I guess I must do the trick inside the OnRender() override function... :(

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YvesDaoust · Accepted Answer · 2012-11-02T05:39:00

As a workaround, you can bind an auxiliary TextBox to the ComboBox so that it reflects the text. Then attach your handler to the TextBox TextChanged event and make the TextBox invisible.

<combobox height="23" horizontalalignment="Left" margin="98,53,0,0" name="comboBox1" verticalalignment="Top" width="120" iseditable="True" />
<textbox height="23" horizontalalignment="Left" margin="100,95,0,0" name="textBox1" verticalalignment="Top" width="120">Text="{Binding ElementName=comboBox1, Path=Text}" TextChanged="textBox1_TextChanged" Visibility="Hidden" /></textbox>

Works fine for me.

Clifford Nelson · Accepted Answer · 2012-11-02T09:17:00

Solution 2

It appears not: http://www.go4answers.com/Example/comboboxs-textchanged-event-60975.aspx[^].

Posted 2-Nov-12 9:17am

Clifford Nelson