Fix trim warnings

Author: Shane32

QRCoder/Extensions/StringValueAttribute.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Reflection;
 using System.Text;
@@ -9,6 +10,7 @@ namespace QRCoder.Extensions
     /// <summary>
     /// Used to represent a string value for a value in an enum
     /// </summary>
+    [Obsolete("This attribute will be removed in a future version of QRCoder.")]
     public class StringValueAttribute : Attribute
     {
 
@@ -31,13 +33,17 @@ public StringValueAttribute(string value)
         }        
     }
 
+    [Obsolete("This class will be removed in a future version of QRCoder.")]
     public static class CustomExtensions
     {
         /// <summary>
         /// Will get the string value for a given enum's value
         /// </summary>
         /// <param name="value"></param>
         /// <returns></returns>
+#if NET6_0_OR_GREATER
+        [RequiresUnreferencedCode("This method uses reflection to examine the provided enum value.")]
+#endif
         public static string GetStringValue(this Enum value)
         {            
 #if NETSTANDARD1_3

QRCoder/PayloadGenerator.cs

@@ -4,6 +4,7 @@
 using System.Globalization;
 using System.Text;
 using System.Text.RegularExpressions;
+using System.Diagnostics.CodeAnalysis;
 #if NETSTANDARD1_3
 using System.Reflection;
 #endif
@@ -2477,14 +2478,12 @@ public class RussiaPaymentOrder : Payload
 
             //base
             private CharacterSets characterSet;
-            private MandatoryFields mFields;
-            private OptionalFields oFields;
+            private readonly MandatoryFields mFields = new MandatoryFields();
+            private readonly OptionalFields oFields = new OptionalFields();
             private string separator = "|";
 
             private RussiaPaymentOrder()
             {
-                mFields = new MandatoryFields();
-                oFields = new OptionalFields();
             }
 
             /// <summary>
@@ -2596,7 +2595,7 @@ private string DetermineSeparator()
             private List<string> GetOptionalFieldsAsList()
             {
 #if NETSTANDARD1_3
-                return oFields.GetType().GetRuntimeProperties()
+                return typeof(OptionalFields).GetRuntimeProperties()
                         .Where(field => field.GetValue(oFields) != null)
                         .Select(field => {
                             var objValue = field.GetValue(oFields, null);
@@ -2605,7 +2604,7 @@ private List<string> GetOptionalFieldsAsList()
                         })
                         .ToList();
 #else
-                return oFields.GetType().GetProperties()
+                return typeof(OptionalFields).GetProperties()
                         .Where(field => field.GetValue(oFields, null) != null)
                         .Select(field => {
                             var objValue = field.GetValue(oFields, null);
@@ -2624,7 +2623,7 @@ private List<string> GetOptionalFieldsAsList()
             private List<string> GetMandatoryFieldsAsList()
             {
 #if NETSTANDARD1_3
-                return mFields.GetType().GetRuntimeFields()
+                return typeof(MandatoryFields).GetRuntimeFields()
                         .Where(field => field.GetValue(mFields) != null)
                         .Select(field => {
                             var objValue = field.GetValue(mFields);
@@ -2633,7 +2632,7 @@ private List<string> GetMandatoryFieldsAsList()
                         })
                         .ToList();
 #else
-                return mFields.GetType().GetFields()
+                return typeof(MandatoryFields).GetFields()
                         .Where(field => field.GetValue(mFields) != null)
                         .Select(field => {
                             var objValue = field.GetValue(mFields);

QRCoder/SvgQRCode.cs

@@ -362,7 +362,7 @@ public MediaType GetMediaType()
             /// <returns></returns>
             public string GetDataUri()
             {
-                return $"data:{_mediaType.GetStringValue()};base64,{_logoData}";
+                return $"data:{GetMimeType(_mediaType)};base64,{_logoData}";
             }
 
             /// <summary>
@@ -388,11 +388,29 @@ public bool FillLogoBackground()
             /// </summary>
             public enum MediaType : int
             {
+#pragma warning disable CS0618 // Type or member is obsolete
                 [StringValue("image/png")]
-                PNG = 0, 
+#pragma warning restore CS0618 // Type or member is obsolete
+                PNG = 0,
+#pragma warning disable CS0618 // Type or member is obsolete
                 [StringValue("image/svg+xml")]
+#pragma warning restore CS0618 // Type or member is obsolete
                 SVG = 1
             }
+
+            private string GetMimeType(MediaType type)
+            {
+                switch (type)
+                {
+                    case MediaType.PNG:
+                        return "image/png";
+                    case MediaType.SVG:
+                        return "image/svg+xml";
+                    default:
+                        throw new ArgumentOutOfRangeException(nameof(type));
+                }
+            }
+                
         }
     }