Question

I’m trying to setup a TextBox subclass that will change its style based on a few different things, and I’m running into two problems. The first Trigger, the VisualBrush one, triggers properly but won’t write the text in the String myName. I tried making myName a property but for some reason the set method throws a StackOverFlowException.

The second problem is with the DataTrigger, which isn’t getting triggered even though isRequired is set to false.

This is all within a custom control that inherits TextBox.

Here’s my XAML:

    <TextBox.Style>
    <Style TargetType="TextBox">
        <Style.Triggers>
            <Trigger Property="Text" Value="">
                <Setter Property="Background">
                    <Setter.Value>
                        <VisualBrush Stretch="None">
                            <VisualBrush.Visual>
                                <TextBlock Foreground="Gray" FontSize="24">
                                        <TextBlock.Text>
                                            <Binding Path="myName" RelativeSource="{RelativeSource Self}" />
                                        </TextBlock.Text>
                                </TextBlock>
                            </VisualBrush.Visual>
                        </VisualBrush>
                    </Setter.Value>
                </Setter>
            </Trigger>
            <DataTrigger Binding="{Binding Path=isRequired, Source={RelativeSource Self}}" Value="False">
                <Setter Property="Text" Value="100" />
            </DataTrigger>
        </Style.Triggers>
    </Style>
</TextBox.Style>

CS:

    public partial class SuperTB : TextBox
{
    public String myName
    {
        get { return myName; }
        set {}
    }

    DependencyProperty isRequiredProperty = DependencyProperty.Register("isRequired", typeof(Boolean), typeof(SuperTB));

    public Boolean isRequired
    {
        get { return (Boolean)GetValue(isRequiredProperty); }
        set { SetValue(isRequiredProperty, value); }
    }

    public SuperTB()
    {
        InitializeComponent();
        myName = "Unicorns!";
    }

}

This is the code that StackOverflows it. Also failing to work but no Exception is:

public string myName = "Rainbows!";

Answer 1

 public string myName    
 {        
     get { return myName; }        
     set {}    
 }

that property getter is returning itself, hence the stack overflow.

and the setter is doing nothing, hence the “failing to work”

you probably want:

 private string myName; // lower case!
 public string MyName    // upper case!
 {        
     get { return myName; }        
     set { myName = value; }    
 }

or even

 public string myName { get; set; }

and even then this still won’t work like you expect, since nothing is firing any property change notifications there, so nobody will notice that myName ever changes.