Fix nullability mismatch in WPF converters

DiscordChatExporter.Gui/Converters/ChannelToGroupKeyConverter.cs

@@ -10,7 +10,12 @@ public class ChannelToGroupKeyConverter : IValueConverter
 {
     public static ChannelToGroupKeyConverter Instance { get; } = new();
 
-    public object? Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
+    public object? Convert(
+        object? value,
+        Type targetType,
+        object? parameter,
+        CultureInfo culture
+    ) =>
         value switch
         {
             Channel { IsThread: true, Parent: not null } channel
@@ -22,9 +27,9 @@ public class ChannelToGroupKeyConverter : IValueConverter
         };
 
     public object ConvertBack(
-        object value,
+        object? value,
         Type targetType,
-        object parameter,
+        object? parameter,
         CultureInfo culture
     ) => throw new NotSupportedException();
 }

DiscordChatExporter.Gui/Converters/DateTimeOffsetToDateTimeConverter.cs

@@ -9,15 +9,20 @@ public class DateTimeOffsetToDateTimeConverter : IValueConverter
 {
     public static DateTimeOffsetToDateTimeConverter Instance { get; } = new();
 
-    public object? Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
+    public object? Convert(
+        object? value,
+        Type targetType,
+        object? parameter,
+        CultureInfo culture
+    ) =>
         value is DateTimeOffset dateTimeOffsetValue
             ? dateTimeOffsetValue.DateTime
             : default(DateTime?);
 
     public object? ConvertBack(
-        object value,
+        object? value,
         Type targetType,
-        object parameter,
+        object? parameter,
         CultureInfo culture
     ) =>
         value is DateTime dateTimeValue

DiscordChatExporter.Gui/Converters/ExportFormatToStringConverter.cs

@@ -10,13 +10,17 @@ public class ExportFormatToStringConverter : IValueConverter
 {
     public static ExportFormatToStringConverter Instance { get; } = new();
 
-    public object? Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
-        value is ExportFormat exportFormatValue ? exportFormatValue.GetDisplayName() : default;
+    public object? Convert(
+        object? value,
+        Type targetType,
+        object? parameter,
+        CultureInfo culture
+    ) => value is ExportFormat exportFormatValue ? exportFormatValue.GetDisplayName() : default;
 
     public object ConvertBack(
-        object value,
+        object? value,
         Type targetType,
-        object parameter,
+        object? parameter,
         CultureInfo culture
     ) => throw new NotSupportedException();
 }

DiscordChatExporter.Gui/Converters/InverseBoolConverter.cs

@@ -9,13 +9,13 @@ public class InverseBoolConverter : IValueConverter
 {
     public static InverseBoolConverter Instance { get; } = new();
 
-    public object Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
+    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture) =>
         value is false;
 
     public object ConvertBack(
-        object value,
+        object? value,
         Type targetType,
-        object parameter,
+        object? parameter,
         CultureInfo culture
     ) => value is false;
 }

DiscordChatExporter.Gui/Converters/SnowflakeToDateTimeOffsetConverter.cs

@@ -10,13 +10,17 @@ public class SnowflakeToDateTimeOffsetConverter : IValueConverter
 {
     public static SnowflakeToDateTimeOffsetConverter Instance { get; } = new();
 
-    public object? Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
-        value is Snowflake snowflake ? snowflake.ToDate() : null;
+    public object? Convert(
+        object? value,
+        Type targetType,
+        object? parameter,
+        CultureInfo culture
+    ) => value is Snowflake snowflake ? snowflake.ToDate() : null;
 
     public object ConvertBack(
-        object value,
+        object? value,
         Type targetType,
-        object parameter,
+        object? parameter,
         CultureInfo culture
     ) => throw new NotSupportedException();
 }

DiscordChatExporter.Gui/Converters/TimeSpanToDateTimeConverter.cs

@@ -9,13 +9,17 @@ public class TimeSpanToDateTimeConverter : IValueConverter
 {
     public static TimeSpanToDateTimeConverter Instance { get; } = new();
 
-    public object? Convert(object value, Type targetType, object parameter, CultureInfo culture) =>
-        value is TimeSpan timeSpanValue ? DateTime.Today.Add(timeSpanValue) : default(DateTime?);
+    public object? Convert(
+        object? value,
+        Type targetType,
+        object? parameter,
+        CultureInfo culture
+    ) => value is TimeSpan timeSpanValue ? DateTime.Today.Add(timeSpanValue) : default(DateTime?);
 
     public object? ConvertBack(
-        object value,
+        object? value,
         Type targetType,
-        object parameter,
+        object? parameter,
         CultureInfo culture
     ) => value is DateTime dateTimeValue ? dateTimeValue.TimeOfDay : default(TimeSpan?);
 }