Merge pull request #2377 from EPPlusSoftware/bug/issue2376

Fixes issue 2376

Author: OssianEPPlus

src/EPPlus/Core/CellStore/RangeDictionary.cs

@@ -133,6 +133,7 @@ internal bool Exists(int row, int col)
         }
         internal List<T> GetValuesFromRange(int fromRow, int fromCol, int toRow, int toCol)
         {
+            if (_addresses.Keys.Count == 0) return new List<T>();
             var hs = new HashSet<T>();
             long rowSpan = ((fromRow - 1) << 20) | (fromRow - 1);
             var searchItem = new RangeItem(rowSpan, default);

src/EPPlusTest/DataValidation/DataValidationTests.cs

@@ -1295,5 +1295,12 @@ public void DataValidationsPerformance()
                 SaveAndCleanup(p);
             }
         }
-    }    
+        [TestMethod]
+        public void VerifyClearDataValidationOnEmptyRange()
+        {
+            using var p = new ExcelPackage();
+            var ws = p.Workbook.Worksheets.Add("Sheet1");
+            ws.Cells[1, 1, 4, 4].DataValidation.ClearDataValidation();
+        }
+    }
 }