I have a WPF user control containing the textbox and the button. The textbox has the validation rule associated(which executes some business rule. This class implements ValidationRule). The button needs to be enabled/disabled based on the textbox validation result.

The validation of the textbox is happening properly.

The enabled/disabling of the button is not happening properly. Once the button gets enabled, it does not get disabled even if the validation of the textbox results in error.

      <TextBox MaxLength="3" Width="40" Margin="5" x:Name="Text1" HorizontalContentAlignment="Center">
                <TextBox.Text>
                    <Binding Path="Densities[0].Value" UpdateSourceTrigger="PropertyChanged" >
                        <Binding.ValidationRules>
                            <administration:ValidateDensityRule/>
                        </Binding.ValidationRules>
                    </Binding>
                </TextBox.Text>
      </TextBox>

Button Xaml

<Button.Style>
    <Style TargetType="{x:Type Button}" BasedOn="{StaticResource ButtonStyle}">
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding Text1,Path=(Validation.HasError)}" Value="True">
                                <Setter Property="IsEnabled" Value="False"></Setter>                                    
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </Button.Style>

What am i missing here ?