Remove a call to Type.GetProperty to improve AOT support (#2048)

EPPlus is mostly usable in a native AOT compilation context. One exception to
this support is the use of the reflection method Type.GetProperty in
TypeCompat.GetPropertyValue.

Fortunately, there is only one place where this method is used, in
ExcelVBACollectionBase. By adding a type constraint on the generic type T of
ExcelVBACollectionBase, we can get rid of the use of reflection.

In practice, an AOT compiled project that uses EPPlus to read an Excel file
that contains VBA macro could throw NullReferenceExceptions.

Author: oreadvanthink

src/EPPlus/Compatibility/TypeCompat.cs

@@ -45,13 +45,5 @@ internal static bool IsGenericType(Type t)
 #endif
 
         }
-        public static object GetPropertyValue(object v, string name)
-        {
-#if (Core)
-            return v.GetType().GetTypeInfo().GetProperty(name).GetValue(v, null);
-#else
-            return v.GetType().GetProperty(name).GetValue(v, null);
-#endif
-        }
     }
 }

src/EPPlus/Vba/ExcelVBACollectionBase.cs

@@ -20,7 +20,7 @@ namespace OfficeOpenXml.VBA
     /// Base class for VBA collections
     /// </summary>
     /// <typeparam name="T"></typeparam>
-    public class ExcelVBACollectionBase<T> : IEnumerable<T>
+    public class ExcelVBACollectionBase<T> : IEnumerable<T> where T : IExcelVBACollectionElement
     {
         /// <summary>
         /// A list of vba objects
@@ -48,7 +48,7 @@ public T this [string Name]
         {
             get
             {
-                return _list.Find((f) => TypeCompat.GetPropertyValue(f,"Name").ToString().Equals(Name,StringComparison.OrdinalIgnoreCase));
+                return _list.Find((f) => f.Name.ToString().Equals(Name,StringComparison.OrdinalIgnoreCase));
             }
         }
         /// <summary>
@@ -77,7 +77,7 @@ public int Count
         /// <returns>True if the name exists</returns>
         public bool Exists(string Name)
         {
-            return _list.Exists((f) => TypeCompat.GetPropertyValue(f,"Name").ToString().Equals(Name,StringComparison.OrdinalIgnoreCase));
+            return _list.Exists((f) => f.Name.ToString().Equals(Name,StringComparison.OrdinalIgnoreCase));
         }
         /// <summary>
         /// Removes the item

src/EPPlus/Vba/ExcelVBAReference.cs

@@ -15,7 +15,7 @@ namespace OfficeOpenXml.VBA
     /// <summary>
     /// A VBA reference
     /// </summary>
-    public class ExcelVbaReference
+    public class ExcelVbaReference : IExcelVBACollectionElement
     {
         /// <summary>
         /// Constructor.

src/EPPlus/Vba/ExcelVbaModule.cs

@@ -21,7 +21,7 @@ namespace OfficeOpenXml.VBA
     /// <summary>
     /// A VBA code module. 
     /// </summary>
-    public class ExcelVBAModule
+    public class ExcelVBAModule : IExcelVBACollectionElement
     {
         string _name = "";
         ModuleNameChange _nameChangeCallback = null;

src/EPPlus/Vba/ExcelVbaModuleAttribute.cs

@@ -15,7 +15,7 @@ namespace OfficeOpenXml.VBA
     /// <summary>
     /// A VBA modual attribute
     /// </summary>
-    public class ExcelVbaModuleAttribute
+    public class ExcelVbaModuleAttribute : IExcelVBACollectionElement
     {
         internal ExcelVbaModuleAttribute()
         {

src/EPPlus/Vba/IExcelVBACollectionElement.cs

@@ -0,0 +1,9 @@
+namespace OfficeOpenXml.VBA {
+
+    /// <summary>
+    /// The interface that must be implemented by the elements stored by ExcelVBACollectionBase.
+    /// </summary>
+    public interface IExcelVBACollectionElement {
+        string Name{get;}
+    }
+}