Null Converters

These converters handle null values and convert them to boolean states or visibility for UI binding scenarios.

NotNullConverter

• Namespace: GenHub.Infrastructure.Converters
• Purpose: Converts any value to true if it's not null, false if it is null
• Return Type: bool

Basic Usage

<TextBlock Text="Has Value"
           IsVisible="{Binding SelectedItem, Converter={StaticResource NotNullConverter}}" />

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NotNullOrEmptyConverter

• Namespace: GenHub.Infrastructure.Converters
• Purpose: Converts a value to true if it's not null and not an empty string
• Return Type: bool
• Logic: Returns true if value is not null, or if it's a string and not empty

String/Object Usage

<Button Content="Search"
        IsEnabled="{Binding SearchQuery, Converter={StaticResource NotNullOrEmptyConverter}}" />

Examples

<!-- String property -->
<TextBlock IsVisible="{Binding UserName, Converter={StaticResource NotNullOrEmptyConverter}}" />

<!-- Object property -->
<Border IsVisible="{Binding SelectedProfile, Converter={StaticResource NotNullConverter}}" />

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NullToVisibilityConverter

• Namespace: GenHub.Infrastructure.Converters
• Purpose: Converts null values to "Collapsed" and non-null values to "Visible"
• Return Type: string ("Visible" or "Collapsed")

Visibility Usage

<TextBlock Text="No selection"
           IsVisible="{Binding SelectedItem, Converter={StaticResource NullToVisibilityConverter}}" />

Inverted Logic

For the inverse (show when null, hide when not null), you can combine with other converters or create a custom one.

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NullSafePropertyConverter

• Namespace: GenHub.Infrastructure.Converters
• Purpose: Safely handles null values in property binding, returning a fallback value
• Parameters:
  • ConverterParameter: Optional fallback string to return for null values

Property Binding Usage

<TextBlock Text="{Binding User.Name, Converter={StaticResource NullSafePropertyConverter},
                          ConverterParameter='Unknown User'}" />

Two-Way Binding

This converter supports two-way binding, making it useful for editable fields:

<TextBox Text="{Binding User.Description, Converter={StaticResource NullSafePropertyConverter},
                        ConverterParameter='No description'}" />

Real Usage in GameProfileCardView.axaml

<!-- Show version info only when available -->
<TextBlock Text="{Binding VersionId}" 
           IsVisible="{Binding VersionId, Converter={StaticResource NotNullOrEmptyConverter}}" />

<!-- Show source type badge conditionally -->
<Border IsVisible="{Binding SourceTypeName, Converter={StaticResource NotNullOrEmptyConverter}}">
    <TextBlock Text="{Binding SourceTypeName}" />
</Border>

<!-- Show workflow info when present -->
<StackPanel IsVisible="{Binding WorkflowNumber, Converter={StaticResource NotNullOrEmptyConverter}}">
    <TextBlock Text="Workflow:" />
    <TextBlock Text="{Binding WorkflowNumber}" />
</StackPanel>

<!-- Show PR info conditionally -->
<StackPanel IsVisible="{Binding PullRequestNumber, Converter={StaticResource NotNullOrEmptyConverter}}">
    <TextBlock Text="PR:" />
    <TextBlock Text="{Binding PullRequestNumber}" />
</StackPanel>

<!-- Show commit info when available -->
<StackPanel IsVisible="{Binding CommitSha, Converter={StaticResource NotNullOrEmptyConverter}}">
    <TextBlock Text="Commit:" />
    <TextBlock Text="{Binding CommitSha}" />
</StackPanel>

<!-- Show build info section -->
<Border IsVisible="{Binding BuildInfo, Converter={StaticResource NotNullConverter}}">
    <StackPanel>
        <!-- Compiler info with null safety -->
        <TextBlock IsVisible="{Binding BuildInfo, Converter={StaticResource NullSafeConverter}, ConverterParameter=Compiler, FallbackValue=False}">
            Compiler: <TextBlock Text="{Binding BuildInfo.Compiler}" />
        </TextBlock>
        
        <!-- Configuration info -->
        <TextBlock IsVisible="{Binding BuildInfo, Converter={StaticResource NullSafeConverter}, ConverterParameter=Configuration, FallbackValue=False}">
            Config: <TextBlock Text="{Binding BuildInfo.Configuration}" />
        </TextBlock>
        
        <!-- Build flags -->
        <TextBlock IsVisible="{Binding BuildInfo, Converter={StaticResource NullSafeConverter}, ConverterParameter=HasTFlag, FallbackValue=False}">
            T-Flag: <TextBlock Text="{Binding BuildInfo.HasTFlag}" />
        </TextBlock>
    </StackPanel>
</Border>

Real Usage in GameProfileSettingsWindow.axaml

<!-- Show version details when selected -->
<Border IsVisible="{Binding SelectedVersion, Converter={StaticResource NotNullConverter}, FallbackValue=False}">
    <TextBlock Text="{Binding SelectedVersion.Name}" />
</Border>

<!-- Show build date when available -->
<StackPanel IsVisible="{Binding SelectedVersion.BuildDate, Converter={StaticResource NotNullConverter}}">
    <TextBlock Text="Built:" />
    <TextBlock Text="{Binding SelectedVersion.BuildDate}" />
</StackPanel>

<!-- Show source type info -->
<Border IsVisible="{Binding SelectedVersion.SourceType, Converter={StaticResource NotNullConverter}}">
    <TextBlock Text="{Binding SelectedVersion.SourceType}" />
</Border>