DataTrigger Not Triggering

Question

I'm getting SO frustrated here.. I can't get these datatriggers to consistently work..

It works when I first run the program as I initialize a global UdpMessageAuthentication class (as it sets it to "test0"... but then I have a button that calls the SendAuthPacket method.. and from debugging I see it go into the OnPropertyChanged when I hit the button but the label won't change caption or color or any other property...once I use AuthenticateStatus to "test1".

Obviously I tried more realistic variables besides test0 and test1 but no matter what I'm doing I can't get the triggers to update

Please help =T

<Label Name="Label_Authentication" Margin="5,0,0,0" VerticalAlignment="Center" Grid.Column="0" FontSize="14">
<Label.Style>
    <Style TargetType="Label">
        <Setter Property="Content" Value="Initial Content"></Setter>
        <Setter Property="Foreground" Value ="Red"></Setter>

        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=AuthenticateStatus}" Value="test0">
                <Setter Property="Content" Value="Authentication Required" />
                <Setter Property="Foreground" Value="Red"></Setter>
            </DataTrigger>
            <DataTrigger Binding="{Binding Path=AuthenticateStatus}" Value="test1">
                <Setter Property="Content" Value="Attempting Authentication..." />
                <Setter Property="Background" Value="Blue"></Setter>
            </DataTrigger>
            etc....


public class UdpMessageAuthentication : INotifyPropertyChanged
{
    private string _authenticateStatus;

    public string AuthenticateStatus
    {
        get { return _authenticateStatus; }
        set
        {
            if (_authenticateStatus != value)
            {
                _authenticateStatus = value;
                OnPropertyChanged("Authenticate Status");
            }
        }
    }

    public UdpMessageAuthentication()
    {
        _udpClient = new UdpClient();
        AuthenticateStatus = "test0";
    }

    public void SendAuthPacket(IPAddress ip, string userID)
    {
        etc etc....
        AuthenticateStatus = "test1";
        etc etc....
    }

David David · Accepted Answer · 2014-05-19T20:45:28

Make sure you explicitly set the Mode Property when you use (any) binding.

<DataTrigger Binding="{Binding Path=AuthenticateStatus, Mode=OneWay}" Value="test0">

Also, you have to make sure you're raising the property changed event with the PropertyName string set to exactly the name of the proprty being raised, since the system is using Reflection under the hood to find the changed property based on said string. Thus, try using this in your ViewModel:

get { return _authenticateStatus; }
set
{
    if (_authenticateStatus != value)
    {
        _authenticateStatus = value;
        OnPropertyChanged("AuthenticateStatus");
    }
}

DataTrigger Not Triggering

1 Answers