INotifyPropertyChanged for a Textbox in style - wpf

Question

I am trying to rename a column in WPF data grid. I am providing context-menu to user for column rename. Once user clicks on the rename from a column-header of particular column, I am applying a style to the column-header using following code and style.
private void RenameColumn_Executed(object sender, ExecutedRoutedEventArgs e)
{
if (e != null)
{
if (e.Parameter != null)
{
if ((e.Parameter as DataGridColumnHeader) != null)
{
this.DefaultColHeaderStyle = (e.Parameter as DataGridColumnHeader).Style;
this.RenamedColIndex = (e.Parameter as DataGridColumnHeader).DisplayIndex;
(this.grTestData.ColumnFromDisplayIndex(this.RenamedColIndex)).HeaderStyle = this.grTestData.Resources["RenameColumnHeader"] as Style;
}
}
}
}
I am binding this text-box to a properpty:
<Style x:Key="RenameColumnHeader" TargetType="{x:Type DataGridColumnHeader}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Grid FocusManager.FocusedElement="{Binding ElementName=txtBxRename}">
<TextBox x:Name="txtBxRename" GotFocus="txtBxRename_GotFocus" LostFocus="txtBxRename_LostFocus" KeyDown="txtBxRename_KeyDown" TextChanged="txtBxRename_TextChanged" Text="{Binding Path=NewColName,Mode=TwoWay}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
I have implemented INotifyPropertyChanged interface for property NewColName:
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
public string NewColName
{
get
{
return this.newColName;
}
set
{
this.newColName = value;
this.OnPropertyChanged("NewColName");
}
}
but it is not triggering the property-changed when i start typing in the text-box. I am trying to implement IDataErrorInfo for the text-box validation. Please guide me. Do let me know if you need any other information about my code.

Answer 1

You probably will need to set the Binding.UpdateSourceTrigger to PropertyChanged, as for TextBox.Text it is LostFocus by default.

Answer 2

It has been solved.
Whenever we are binding a control declared within a style, we need to give a name to the window.
<Window x:Class="DataGridColumnRename.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:cmd="clr-namespace:DataGridColumnRename"
Title="MainWindow" Height="350" Width="525" Name="Me">
And in the control within the style we need to specify the ElementName Property and assign windown name (in this case it is 'Me') to it.
<Style x:Key="RenameColumnHeader" TargetType="{x:Type DataGridColumnHeader}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Grid FocusManager.FocusedElement="{Binding ElementName=txtBxRename}">
<TextBox x:Name="txtBxRename" GotFocus="txtBxRename_GotFocus" LostFocus="txtBxRename_LostFocus" KeyDown="txtBxRename_KeyDown" Text="{Binding ElementName=Me, Path=NewColName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
Then only it triggers INotifyPropertyChanged. :) :) Thanks for the help guys.