feat: Add ObjectNotNullToVisibilityCollapsedValueConverter and ObjectNullToVisibilityVisibleValueConverter

Author: davidkallesen

src/Atc.Wpf/ValueConverters/@Readme.md

@@ -43,8 +43,10 @@
 | Null -> X                 | NullCheckValueConverter                                  | NULL -> Parameter if set                | Not supported                           |
 | Null -> UnsetValue        | NullToUnsetValueConverter                                | NULL -> DependencyProperty.UnsetValue   | Object -> DependencyProperty.UnsetValue |
 | Object -> Bool            | ObjectNotNullToBoolValueConverter                        | NotNULL -> True                         | Not supported                           |
+| Object -> Visibility      | ObjectNotNullToVisibilityCollapsedValueConverter         | NotNULL -> Collapsed                      | Not supported                           |
 | Object -> Visibility      | ObjectNotNullToVisibilityVisibleValueConverter           | NotNULL -> Visible                      | Not supported                           |
 | Object -> Visibility      | ObjectNullToVisibilityCollapsedValueConverter            | NULL -> Collapsed                       | Not supported                           |
+| Object -> Visibility      | ObjectNullToVisibilityVisibleValueConverter              | NULL -> Visible                         | Not supported                           |
 | Object[] -> Visibility    | MultiObjectNullToVisibilityCollapsedValueConverter       | All-NULL -> Collapsed                   | Not supported                           |
 | Object -> Bool            | ObjectNullToBoolValueConverter                           | NULL => True                            | Not supported                           |
 

src/Atc.Wpf/ValueConverters/ObjectNotNullToVisibilityCollapsedValueConverter.cs

@@ -0,0 +1,31 @@
+namespace Atc.Wpf.ValueConverters;
+
+/// <summary>
+/// ValueConverter: Object NotNull To Visibility-Collapsed.
+/// </summary>
+[ValueConversion(typeof(object), typeof(Visibility), ParameterType = typeof(Visibility))]
+public sealed class ObjectNotNullToVisibilityCollapsedValueConverter : IValueConverter
+{
+    public Visibility NonVisibility { get; set; } = Visibility.Visible;
+
+    /// <inheritdoc />
+    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        var nonVisibility = NonVisibility;
+
+        if (parameter is Visibility visibility and Visibility.Visible)
+        {
+            nonVisibility = visibility;
+        }
+
+        return value is null
+            ? nonVisibility
+            : Visibility.Collapsed;
+    }
+
+    /// <inheritdoc />
+    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        throw new NotSupportedException("This is a OneWay converter.");
+    }
+}

src/Atc.Wpf/ValueConverters/ObjectNullToVisibilityVisibleValueConverter.cs

@@ -0,0 +1,22 @@
+namespace Atc.Wpf.ValueConverters;
+
+/// <summary>
+/// ValueConverter: Object Null To Visibility-Visible.
+/// </summary>
+[ValueConversion(typeof(object), typeof(Visibility))]
+public sealed class ObjectNullToVisibilityVisibleValueConverter : IValueConverter
+{
+    /// <inheritdoc />
+    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        return value is null
+            ? Visibility.Visible
+            : Visibility.Collapsed;
+    }
+
+    /// <inheritdoc />
+    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        throw new NotSupportedException("This is a OneWay converter.");
+    }
+}

test/Atc.Wpf.Tests/ValueConverters/ObjectNotNullToVisibilityCollapsedValueConverterTests.cs

@@ -0,0 +1,44 @@
+namespace Atc.Wpf.Tests.ValueConverters;
+
+public class ObjectNotNullToVisibilityCollapsedValueConverterTests
+{
+    private readonly IValueConverter converter = new ObjectNotNullToVisibilityCollapsedValueConverter();
+
+    [Theory]
+    [InlineData(Visibility.Visible, null)]
+    [InlineData(Visibility.Collapsed, true)]
+    [InlineData(Visibility.Collapsed, "Hello")]
+    public void Convert(Visibility expected, object? input)
+        => Assert.Equal(
+            expected,
+            converter.Convert(input, targetType: null, parameter: null, culture: null));
+
+    [Theory]
+    [InlineData(Visibility.Visible, null, null)]
+    [InlineData(Visibility.Collapsed, true, null)]
+    [InlineData(Visibility.Collapsed, "Hello", null)]
+    [InlineData(Visibility.Visible, null, Visibility.Collapsed)]
+    [InlineData(Visibility.Collapsed, true, Visibility.Collapsed)]
+    [InlineData(Visibility.Collapsed, "Hello", Visibility.Collapsed)]
+    [InlineData(Visibility.Visible, null, Visibility.Hidden)]
+    [InlineData(Visibility.Collapsed, true, Visibility.Hidden)]
+    [InlineData(Visibility.Collapsed, "Hello", Visibility.Hidden)]
+    [InlineData(Visibility.Visible, null, Visibility.Visible)]
+    [InlineData(Visibility.Collapsed, true, Visibility.Visible)]
+    [InlineData(Visibility.Collapsed, "Hello", Visibility.Visible)]
+    public void Convert_Parameter(Visibility expected, object? input, object? parameter)
+        => Assert.Equal(
+            expected,
+            converter.Convert(input, targetType: null, parameter, culture: null));
+
+    [Fact]
+    public void ConvertBack_Should_Throw_Exception()
+    {
+        // Act
+        var exception = Record.Exception(() => converter.ConvertBack(value: null, targetType: null, parameter: null, culture: null));
+
+        // Assert
+        Assert.IsType<NotSupportedException>(exception);
+        Assert.Equal("This is a OneWay converter.", exception.Message);
+    }
+}

test/Atc.Wpf.Tests/ValueConverters/ObjectNullToVisibilityVisibleValueConverterTests.cs

@@ -0,0 +1,26 @@
+namespace Atc.Wpf.Tests.ValueConverters;
+
+public class ObjectNullToVisibilityVisibleValueConverterTests
+{
+    private readonly IValueConverter converter = new ObjectNullToVisibilityVisibleValueConverter();
+
+    [Theory]
+    [InlineData(Visibility.Visible, null)]
+    [InlineData(Visibility.Collapsed, true)]
+    [InlineData(Visibility.Collapsed, "Hello")]
+    public void Convert(Visibility expected, object? input)
+        => Assert.Equal(
+            expected,
+            converter.Convert(input, targetType: null, parameter: null, culture: null));
+
+    [Fact]
+    public void ConvertBack_Should_Throw_Exception()
+    {
+        // Act
+        var exception = Record.Exception(() => converter.ConvertBack(value: null, targetType: null, parameter: null, culture: null));
+
+        // Assert
+        Assert.IsType<NotSupportedException>(exception);
+        Assert.Equal("This is a OneWay converter.", exception.Message);
+    }
+}