feat: add ReflectionHelper.GetPrivateField<T>

atc-net · Oct 10, 2024 · 890698e · 890698e
1 parent 55ea945
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diff --git a/docs/CodeDoc/Atc/Atc.Helpers.md b/docs/CodeDoc/Atc/Atc.Helpers.md
@@ -1945,16 +1945,27 @@ ReflectionHelper.
 
 ### Static Methods
 
+#### GetPrivateField
+>```csharp
+>T GetPrivateField(object target, string fieldName)
+>```
+><b>Summary:</b> Gets the value of a private field from the specified target object.
+>
+><b>Parameters:</b><br>
+>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`target`&nbsp;&nbsp;-&nbsp;&nbsp;The target object containing the private field.<br />
+>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`fieldName`&nbsp;&nbsp;-&nbsp;&nbsp;The name of the private field to retrieve.<br />
+>
+><b>Returns:</b> The value of the private field, cast to the specified type.
 #### SetPrivateField
 >```csharp
 >void SetPrivateField(object target, string fieldName, object value)
 >```
-><b>Summary:</b> Sets the private field.
+><b>Summary:</b> Sets the value of a private field on the specified target object.
 >
 ><b>Parameters:</b><br>
->&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`target`&nbsp;&nbsp;-&nbsp;&nbsp;The target.<br />
->&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`fieldName`&nbsp;&nbsp;-&nbsp;&nbsp;Name of the field.<br />
->&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`value`&nbsp;&nbsp;-&nbsp;&nbsp;The value.<br />
+>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`target`&nbsp;&nbsp;-&nbsp;&nbsp;The target object containing the private field.<br />
+>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`fieldName`&nbsp;&nbsp;-&nbsp;&nbsp;The name of the private field to set.<br />
+>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`value`&nbsp;&nbsp;-&nbsp;&nbsp;The value to set on the private field.<br />
 
 <br />
 

diff --git a/docs/CodeDoc/Atc/IndexExtended.md b/docs/CodeDoc/Atc/IndexExtended.md
@@ -4669,6 +4669,7 @@
      - KillEntryCaller(int timeoutInSec = 30)
 - [ReflectionHelper](Atc.Helpers.md#reflectionhelper)
   -  Static Methods
+     - GetPrivateField(object target, string fieldName)
      - SetPrivateField(object target, string fieldName, object value)
 - [RegionInfoHelper](Atc.Helpers.md#regioninfohelper)
   -  Static Methods

diff --git a/src/Atc/Helpers/ReflectionHelper.cs b/src/Atc/Helpers/ReflectionHelper.cs
@@ -6,12 +6,14 @@ namespace Atc.Helpers;
 public static class ReflectionHelper
 {
     /// <summary>
-    /// Sets the private field.
+    /// Sets the value of a private field on the specified target object.
     /// </summary>
-    /// <param name="target">The target.</param>
-    /// <param name="fieldName">Name of the field.</param>
-    /// <param name="value">The value.</param>
-    [SuppressMessage("Major Code Smell", "S3011:Reflection should not be used to increase accessibility of classes, methods, or fields", Justification = "OK.")]
+    /// <param name="target">The target object containing the private field.</param>
+    /// <param name="fieldName">The name of the private field to set.</param>
+    /// <param name="value">The value to set on the private field.</param>
+    /// <exception cref="ArgumentNullException">Thrown if the target or field name is null.</exception>
+    /// <exception cref="ArgumentException">Thrown if the private field is not found in the object hierarchy.</exception>
+    [SuppressMessage("Major Code Smell", "S3011:Reflection should not be used to increase accessibility of classes, methods, or fields", Justification = "Reflection required for testing private fields.")]
     [ExcludeFromCodeCoverage]
     public static void SetPrivateField(object target, string fieldName, object value)
     {
@@ -22,27 +24,71 @@ public static void SetPrivateField(object target, string fieldName, object value
 
         if (string.IsNullOrEmpty(fieldName))
         {
-            throw new ArgumentNullOrDefaultException(nameof(fieldName));
+            throw new ArgumentException("Field name cannot be null or empty", nameof(fieldName));
         }
 
+        var fieldInfo = GetFieldInfo(target, fieldName);
+        if (fieldInfo is null)
+        {
+            throw new ArgumentPropertyException($"Field '{fieldName}' not found in type '{target.GetType()}' or its base types.");
+        }
+
+        fieldInfo.SetValue(target, value);
+    }
+
+    /// <summary>
+    /// Gets the value of a private field from the specified target object.
+    /// </summary>
+    /// <typeparam name="T">The type of the field value.</typeparam>
+    /// <param name="target">The target object containing the private field.</param>
+    /// <param name="fieldName">The name of the private field to retrieve.</param>
+    /// <returns>The value of the private field, cast to the specified type.</returns>
+    /// <exception cref="ArgumentNullException">Thrown if the target or field name is null.</exception>
+    /// <exception cref="ArgumentException">Thrown if the private field is not found in the object hierarchy.</exception>
+    [SuppressMessage("Major Code Smell", "S3011:Reflection should not be used to increase accessibility of classes, methods, or fields", Justification = "Reflection required for testing private fields.")]
+    [ExcludeFromCodeCoverage]
+    public static T? GetPrivateField<T>(object target, string fieldName)
+    {
+        if (target is null)
+        {
+            throw new ArgumentNullException(nameof(target));
+        }
+
+        if (string.IsNullOrEmpty(fieldName))
+        {
+            throw new ArgumentException("Field name cannot be null or empty", nameof(fieldName));
+        }
+
+        var fieldInfo = GetFieldInfo(target, fieldName);
+        if (fieldInfo is null)
+        {
+            throw new ArgumentPropertyException($"Field '{fieldName}' not found in type '{target.GetType()}' or its base types.");
+        }
+
+        return (T?)fieldInfo.GetValue(target);
+    }
+
+    /// <summary>
+    /// Retrieves FieldInfo for a private field by name, traversing the inheritance hierarchy.
+    /// </summary>
+    /// <param name="target">The target object containing the private field.</param>
+    /// <param name="fieldName">The name of the private field.</param>
+    /// <returns>FieldInfo object representing the field, or null if not found.</returns>
+    [SuppressMessage("Major Code Smell", "S3011:Make sure that this accessibility bypass is safe here", Justification = "OK.")]
+    private static FieldInfo? GetFieldInfo(object target, string fieldName)
+    {
         var type = target.GetType();
-        FieldInfo? fi = null;
         while (type is not null)
         {
-            fi = type.GetField(fieldName, BindingFlags.Instance | BindingFlags.NonPublic);
-            if (fi is not null)
+            var fieldInfo = type.GetField(fieldName, BindingFlags.Instance | BindingFlags.NonPublic);
+            if (fieldInfo != null)
             {
-                break;
+                return fieldInfo;
             }
 
-            type = type.BaseType!;
-        }
-
-        if (fi is null)
-        {
-            throw new ArgumentPropertyException($"Field '{fieldName}' not found in type hierarchy.");
+            type = type.BaseType;
         }
 
-        fi.SetValue(target, value);
+        return null;
     }
 }