Windows Phone 7 BorderBrush can only be set once?

So I have this validation method which checks the user's input. If the input is wrong or missing it set the border of the text block to red. Otherwise it resets it. However this code does not work at all. Sometimes the border is set to red, othertimes it isn't when it should be etc etc. It is almost like the control is not repainting itself?

What am I doing wrong?

        private SolidColorBrush _errorBorderBrush = new SolidColorBrush(Colors.Red);
        private SolidColorBrush _normalBorderBrush = new SolidColorBrush(Colors.Black);

        private bool Validate()
        {
            if(txtName.Text == string.Empty)
            {
                txtName.BorderBrush = _errorBorderBrush;
                return false;
            }
            else
            {
                txtName.BorderBrush = _normalBorderBrush;
            }

            if (pwdPassword.Password == string.Empty)
            {
                pwdPassword.BorderBrush = _errorBorderBrush;
                return false;
            }
            else
            {
            开发者_开发知识库    pwdPassword.BorderBrush = _normalBorderBrush;
            }

            ...
         }

I had the same problem, and although I'm not an expert on WP7 or SL/WPF development I think the problem has to do with the default TextBox Template's Focused state not reverting the BorderBrush back to it's original setting (the same problem seems to exist with the Background property as well.) I managed to resolve this by using my own template in XAML... I don't have Blend installed so I don't know how to pull out the original template, but based on this page I think the original template is as follows:

<Style TargetType="TextBox">
<Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilyNormal}"/>
<Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMediumLarge}"/>
<Setter Property="Background" Value="{StaticResource PhoneTextBoxBrush}"/>
<Setter Property="Foreground" Value="{StaticResource PhoneTextBoxForegroundBrush}"/>
<Setter Property="BorderBrush" Value="{StaticResource PhoneTextBoxBrush}"/>
<Setter Property="SelectionBackground" Value="{StaticResource PhoneAccentBrush}"/>
<Setter Property="SelectionForeground" Value="{StaticResource PhoneTextBoxSelectionForegroundBrush}"/>
<Setter Property="BorderThickness" Value="{StaticResource PhoneBorderThickness}"/>
<Setter Property="Padding" Value="2"/>
<Setter Property="Template">
    <Setter.Value>
        <ControlTemplate TargetType="TextBox">
            <Grid Background="Transparent">
                <VisualStateManager.VisualStateGroups>
                    <VisualStateGroup x:Name="CommonStates">
                        <VisualState x:Name="Normal"/>
                        <VisualState x:Name="MouseOver"/>
                        <VisualState x:Name="Disabled">
                            <Storyboard>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="EnabledBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0">
                                        <DiscreteObjectKeyFrame.Value>
                                            <Visibility>Collapsed</Visibility>
                                        </DiscreteObjectKeyFrame.Value>
                                    </DiscreteObjectKeyFrame>
                                </ObjectAnimationUsingKeyFrames>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0">
                                        <DiscreteObjectKeyFrame.Value>
                                            <Visibility>Visible</Visibility>
                                        </DiscreteObjectKeyFrame.Value>
                                    </DiscreteObjectKeyFrame>
                                </ObjectAnimationUsingKeyFrames>
                            </Storyboard>
                        </VisualState>
                        <VisualState x:Name="ReadOnly">
                            <Storyboard>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="EnabledBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0">
                                        <DiscreteObjectKeyFrame.Value>
                                            <Visibility>Collapsed</Visibility>
                                        </DiscreteObjectKeyFrame.Value>
                                    </DiscreteObjectKeyFrame>
                                </ObjectAnimationUsingKeyFrames>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0">
                                        <DiscreteObjectKeyFrame.Value>
                                            <Visibility>Visible</Visibility>
                                        </DiscreteObjectKeyFrame.Value>
                                    </DiscreteObjectKeyFrame>
                                </ObjectAnimationUsingKeyFrames>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneTextBoxBrush}"/>
                                </ObjectAnimationUsingKeyFrames>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="DisabledOrReadonlyBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneTextBoxBrush}"/>
                                </ObjectAnimationUsingKeyFrames>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="DisabledOrReadonlyContent">
                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneTextBoxReadOnlyBrush}"/>
                                </ObjectAnimationUsingKeyFrames>
                            </Storyboard>
                        </VisualState>
                    </VisualStateGroup>
                    <VisualStateGroup x:Name="FocusStates">
                        <VisualState x:Name="Focused">
                            <Storyboard>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="EnabledBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneTextBoxEditBackgroundBrush}"/>
                                </ObjectAnimationUsingKeyFrames>
                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="EnabledBorder">
                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneTextBoxEditBorderBrush}"/>
                                </ObjectAnimationUsingKeyFrames>
                            </Storyboard>
                        </VisualState>
                        <VisualState x:Name="Unfocused"/>
                    </VisualStateGroup>
                </VisualStateManager.VisualStateGroups>
                <Border x:Name="EnabledBorder" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Margin="{StaticResource PhoneTouchTargetOverhang}">
                    <ContentControl x:Name="ContentElement" BorderThickness="0" HorizontalContentAlignment="Stretch" Margin="{StaticResource PhoneTextBoxInnerMargin}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="Stretch"/>
                </Border>
                <Border x:Name="DisabledOrReadonlyBorder" BorderBrush="{StaticResource PhoneDisabledBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="Transparent" Margin="{StaticResource PhoneTouchTargetOverhang}" Visibility="Collapsed">
                    <TextBox x:Name="DisabledOrReadonlyContent" Background="Transparent" Foreground="{StaticResource PhoneDisabledBrush}" FontWeight="{TemplateBinding FontWeight}" FontStyle="{TemplateBinding FontStyle}" FontSize="{TemplateBinding FontSize}" FontFamily="{TemplateBinding FontFamily}" IsReadOnly="True" SelectionForeground="{TemplateBinding SelectionForeground}" SelectionBackground="{TemplateBinding SelectionBackground}" TextAlignment="{TemplateBinding TextAlignment}" TextWrapping="{TemplateBinding TextWrapping}" Text="{TemplateBinding Text}" Template="{StaticResource PhoneDisabledTextBoxTemplate}"/>
                </Border>
            </Grid>
        </ControlTemplate>
    </Setter.Value>
</Setter>

I didn't need the Focused state to look different than the Unfocused state, so I changed the FocusStates VisualStateGroup to look as follows:

    <VisualStateGroup x:Name="FocusStates">
    <VisualState x:Name="Focused" />
    <VisualState x:Name="Unfocused"/>
</VisualStateGroup>

Yeah, I know, not the most elegant solution but it worked for me and hopefully this at least helps point you in the right direction!

It could be the return call. return just means return/cancel method. With a return you break out of the method - directly. So if txtName is empty, pwdPassword won't be checked etc.

What you're doing with the colours should work if you're logic is ok. We can't see all of it, but you should be able to step through it in the debuger and see why it might not be being called.

Here's some sample code that works changing the colour from green to red and back on successive button clicks.

Page class fields

SolidColorBrush green = new SolidColorBrush(Colors.Green);
SolidColorBrush red = new SolidColorBrush(Colors.Red);

Button event handler

    if (textBox1.BorderBrush != green) {
        textBox1.BorderBrush = green;
    } else {
        textBox1.BorderBrush = red;
    }

If you're still having trouble I'd suggest creating a repro project. It may reveal the problem to you and if not, you can post it here for people to look at where your problem can be reproduced.