wpf how to get value from textbook in ControlTemplate treeivwitem - wpf

Question

how to get txt_add.text value?
this style applied to TreeViewitem in code behind
<Page.Resources>
<Style TargetType="{x:Type TreeViewItem}" x:Key="add" >
<Setter Property="Background" Value="{DynamicResource WhiteBrush}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem" >
<StackPanel Orientation="Horizontal" Margin="5">
<TextBox Width="300" Controls:TextBoxHelper.Watermark="Account Name" Margin="2" x:Name="txt_add"/>
<Button Content="{x:Static lang:ResLang.insert}" Style="{StaticResource ButtonSystem}" Width="100" Margin="2" Click="Button_AddNewSubOk_Click"/>
<Button Content="{x:Static lang:ResLang.btn_cancel}" Style="{StaticResource ButtonCancel }" Width="100" Margin="2" Click="Button_AddNewSubCancel_Click"/>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Page.Resources>
</Page>

Answer 1

You need to bind it using mvvm pattern, create a viewmodel class which inherits inotifypropertychanged then bind your text to property in that class.
<Window.DataContext>
<model:viewmodel x:Key="viewmodel"/>
</Window.DataContext>
<!-- where ever you got your textbox -->
<TextBox Text="{Binding Mode=TwoWay,Source={StaticResource viewmodel},Path=stringproperty"/>
and simple viewmodel class :
public class viewmodel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public String stringproperty{ get; set; } ;
}
there is simple implementation of "property changed" in web if this is not working for you.
and you can access it like this but this is wrong you should'nt do this
(this.DataContext as viewmodel).stringproperty
after binding only use bindings to access your data , if you need them in some actions or events pass as parameter to "command" you could search about that