Custom control not updating upon PropertyChanged

Question

0.00/5 (No votes)

See more:

I'm trying out custom control that has a label for its header and a textbox for its InputText. The control binds fine but I can't seem toe get it to update on PropertyChanged event. Here is how I did the class:

C#

public static readonly DependencyProperty HeaderProperty = DependencyProperty.Register("Header",typeof(string), typeof(CustomControl), new PropertyMetadata(null));
public static readonly DependencyProperty InputTextProperty = DependencyProperty.Register("InputText",typeof(string), typeof(CustomControl), new FrameWorkPropertyMetadata(null) {BindsTwoWayByDefault = true} );

public string Header
{
   get { return (string)GetValue(HeaderProperty); }
   set { SetValue(HeaderProperty,value; }
}


public string InputText
{
   get { return (string)GetValue(InputTextProperty); }
   set { SetValue(InputTextProperty,value; }
}

and here is the ControlTemplate:

XML

<StackPanel Orientation="Horizontal">
   <TextBlock Text="{Binding Header, RelativeSource={RelativeSource TemplatedParent}}" Margin="0,0,10,0"/>
   <TextBox Text="{Binding InputText, RelativeSource={RelativeSource TemplatedParent}}" MinWidth="150"/>
</StackPanel>

my call for the control looks like this:

XML

<local:CustomControl Header="HeaderText" InputText={Binding InputString, UpdateSourceTrigger=PropertyChanged/>

What did I miss?

Posted 29-Dec-15 2:08am

Lyandor

Add a Solution

2 solutions

Solution 1

What is your DataContext here? just implement INotifyPropertyChanged event for your properties present in the DataContext object.

Posted 30-Dec-15 20:42pm

VR Karthikeyan

Comments

Lyandor 31-Dec-15 3:04am

Hi,

my data context is a public string property in a viewmodel called InputString. This code works if i change focus from the control. What I wanted was calling set on PropertyChanged without moving away focus. I thought setting UpdateSourceTrigger to PropertyChanged would do the trick but it didn't

VR Karthikeyan 31-Dec-15 3:12am

Have you implemented INotifyPropertyChanged interface in your viemodel?

Lyandor 31-Dec-15 3:41am

yes, the viewmodel looks like this:

private string inputString;
public event PropertyChangedEventHandler PropertyChanged;

protected virtual void OnPropertyChanged(string name)
{
PropertyChangedEventHandler hndl = this.PropertyChanged;

if (hndl !=null)
{
var e = new PropertyChangedEventArgs(name);
hndl(this,e);
}
}

public string InputString
{
get { return inputString;}
set
{
inputString = value;
OnPropertyChanged("InputString");
}
}

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Lyandor · Accepted Answer · 2016-02-05T21:02:00

Solution 2

In TextBox Binding, set UpdateSourceTrigger to PropertyChanged. The code becomes like this:

XML

<textbox text="{Binding InputText, UpdateSourceTrigger=PropertyChanged, RelativeSource={RelativeSource TemplatedParent}}" minwidth="150" />

Posted 5-Feb-16 21:02pm

Lyandor