WPF Showing / Hiding a control with triggers - wpf

Question

I'm new to WPF and I trying to create xaml logic to show / hide a control based on the value of the AllowMiscTitle on the ViewModel. The xaml consist of two fields a combobox of the standard tiles ("Mr", "Mrs", ..., "Other") when "Other" is selected I want the textbox to display.
I've created the follow xaml:
<DockPanel Validation.Error="Validation_Error" HorizontalAlignment="Stretch">
<ComboBox ItemsSource="{Binding Path=Titles, Mode=OneTime}"
Text="{Binding Path=Title}"/>
<TextBox x:Name="TxtBxTitle" Margin="5,5" Visibility="Visible">
<TextBox.Style>
<Style>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=AllowMiscTitle}" Value="false">
<Setter Property="TextBox.Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
</DockPanel>

Answer 1

That Trigger won't work because you have set Visibility property explicitly in TextBox
Do it like this:
<TextBox x:Name="TxtBxTitle" Margin="5,5">
<TextBox.Style>
<Style>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=AllowMiscTitle}" Value="false">
<Setter Property="TextBox.Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
The reason for this is Dependency property value precedence.

Answer 2

There is a
<BooleanToVisibilityConverter x:Key="BoolToVis"></BooleanToVisibilityConverter>
You can use it as following
<TextBox Visibility="{Binding YourPropertyName, Converter={StaticResource BoolToVis}}"></TextBox>

Answer 3

If I got your question right:-
If your selected value is binded to some property in the ViewModel like:-
private string _GenderType;
public string GenderType
{
get
{
return _GenderType;
}
set
{
_GenderType= value;
RaisePropertyChanged("GenderType");
In xaml:-
<TextBox.Style>
<Style>
<Setter Property="TextBox.Visibility" value="Hidden"/>
<Style TargetType="{x:Type TextBox}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=GenderType,ElementName=Combo1}" Value="Other">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBox.Style>