Enable nullability in ListViewGroupConverter (#6373)

dotnet · Dec 22, 2021 · 5aca3ed · 5aca3ed
1 parent 57b34a9
commit 5aca3ed
Showing 1 changed file with 8 additions and 11 deletions.
diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/ListViewGroupConverter.cs b/src/System.Windows.Forms/src/System/Windows/Forms/ListViewGroupConverter.cs
@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using System.Collections;
 using System.ComponentModel;
 using System.ComponentModel.Design.Serialization;
@@ -23,7 +21,7 @@ internal class ListViewGroupConverter : TypeConverter
         ///  Determines if this converter can convert an object in the given source type to
         ///  the native type of the converter.
         /// </summary>
-        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
+        public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
         {
             if (sourceType == typeof(string) && context is not null && context.Instance is ListViewItem)
             {
@@ -37,7 +35,7 @@ public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceT
         ///  Gets a value indicating whether this converter can convert an object to the given
         ///  destination type using the context.
         /// </summary>
-        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
+        public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType)
         {
             if (destinationType == typeof(InstanceDescriptor))
             {
@@ -55,7 +53,7 @@ public override bool CanConvertTo(ITypeDescriptorContext context, Type destinati
         /// <summary>
         ///  Converts the given object to the converter's native type.
         /// </summary>
-        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
+        public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
         {
             if (value is string)
             {
@@ -90,17 +88,16 @@ public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo c
         ///  type is string. If this cannot convert to the destination type, this will
         ///  throw a NotSupportedException.
         /// </summary>
-        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
+        public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
         {
             ArgumentNullException.ThrowIfNull(destinationType);
 
             if (destinationType == typeof(InstanceDescriptor) && value is ListViewGroup)
             {
                 ListViewGroup group = (ListViewGroup)value;
-                ConstructorInfo ctor;
 
                 // Header
-                ctor = typeof(ListViewGroup).GetConstructor(new Type[] { typeof(string), typeof(HorizontalAlignment) });
+                ConstructorInfo ctor = typeof(ListViewGroup).GetConstructor(new Type[] { typeof(string), typeof(HorizontalAlignment) })!;
                 Debug.Assert(ctor is not null, "Expected the constructor to exist.");
                 return new InstanceDescriptor(ctor, new object[] { group.Header, group.HeaderAlignment }, false);
             }
@@ -118,7 +115,7 @@ public override object ConvertTo(ITypeDescriptorContext context, CultureInfo cul
         ///  validator is designed for. This will return null if the data type does not support
         ///  a standard set of values.
         /// </summary>
-        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
+        public override StandardValuesCollection? GetStandardValues(ITypeDescriptorContext? context)
         {
             if (context is not null && context.Instance is ListViewItem item && item.ListView is not null)
             {
@@ -141,7 +138,7 @@ public override StandardValuesCollection GetStandardValues(ITypeDescriptorContex
         ///  in an enum data type.  If the list is not exclusive, then there are other valid values
         ///  besides the list of standard values GetStandardValues provides.
         /// </summary>
-        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
+        public override bool GetStandardValuesExclusive(ITypeDescriptorContext? context)
         {
             return true;
         }
@@ -150,7 +147,7 @@ public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
         ///  Determines if this object supports a standard set of values that can be picked
         ///  from a list.
         /// </summary>
-        public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
+        public override bool GetStandardValuesSupported(ITypeDescriptorContext? context)
         {
             return true;
         }