TextChanged Event in UI for WPF

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TextChanged Event

12 Answers 197 Views

ComboBox

This is a migrated thread and some comments may be shown as answers.

12 Answers, 1 is accepted

answered on 22 Jun 2010, 11:33 AM

Hi lkeel,

TextBoxBase.TextChanged is an attached property. Your XAML will look like this:

<telerikInput:RadComboBox Height="20" Width="200" x:Name="combo" TextBoxBase.TextChanged="combo_TextChanged" >

This way you will trigger this event with every symbol you type or every Text change. Then just put the code you want to execute in combo_TextChanged in the code behind.

Let me know if you have further questions.

Best wishes,
Boyan
the Telerik team

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answered on 26 Aug 2015, 11:45 AM

Hi Anna,

RadComboBox does not support TextChanged event by design. However, you have two appraoches that you could use in order to achieve the desired.

The first one is the proposed by Boyan below to use the TextBoxBase.TextChanged attached property:

<telerik:RadComboBox x:Name="rcboDocSize" DisplayMemberPath="FontSizeName" IsEditable="True" MaxDropDownHeight="190" Width="70" SelectionChanged="rcboDocSize_SelectionChanged" StaysOpenOnEdit="True"

TextBoxBase.TextChanged="radComboBox_TextChanged"/>

and in code - behind:

private void radComboBox_TextChanged(object sender, TextChangedEventArgs e)

{

//implement custom logic here

}

The second approach that you could use to handle to the TextChanged event is to get the TextBox placed inside RadComboBox using the ChildrenOfType method (inside the Loaded event) and handle its TextChanged event:

private void radComboBox_Loaded(object sender, RoutedEventArgs e)

{

var combo = sender as RadComboBox;

var textBox = combo.ChildrenOfType<TextBox>().FirstOrDefault();

if(textBox != null)

{

textBox.TextChanged += textBox_TextChanged;

}

void textBox_TextChanged(object sender, TextChangedEventArgs e)

{

//implement custom logic

}

Hopes this helps.

Regards,
Nasko
Telerik

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answered on 28 Aug 2015, 10:52 AM

RadComboBoxWPF.rar

Hello Anna,

We tried to reproduce the observed by you error but it seems everything works as expected on our side.

I am attaching you a sample project that demonstrates the approach with the TextBoxBase.TextChanged attached event - please, check it.

Hopes this helps.

Regards,
Nasko
Telerik

answered on 09 May 2018, 10:37 AM

Hello Flemming,

I checked this on my side and I hit the following error - "Could not find event 'TextChanged' on object of type 'Telerik.Windows.Controls.RadComboBox'.". I am not familiar with the Reactive Linq framework but I will guess that the FromEventPattern method is searching for direct events only. And since the TextChanged is not an event of RadComboBox you can't get the proper event pattern.

To achieve your requirement you can subscribe the Loaded event of the combobox where you can get the TextBox element and use the reactive linq on it.

private void Combobox_Loaded(object sender, RoutedEventArgs e)

{

var textBox = this.combobox.FindChildByType<TextBox>();

var input = from evt in Observable.FromEventPattern(textBox, "TextChanged") select evt;

}

Regards,
Martin Ivanov
Progress Telerik

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