修复空引用

Assets/Unity-Tools/ExcelResolver/Editor/Core/Data/ClassCodeData.cs

@@ -24,6 +24,8 @@ namespace Tools.ExcelResolver.Editor
             fields.Clear();
             fields = null;
 
+            if (keyField != null)
+            {
                 foreach (var fieldData in keyField)
                 {
                     fieldData?.Dispose();
@@ -31,4 +33,5 @@ namespace Tools.ExcelResolver.Editor
                 keyField = null;
             }
         }
+    }
 }