Fixed bug in FILTER function where third parameter should be able to handle error value as input. #2239 (#2244)

Author: karlkallman

src/EPPlus/FormulaParsing/Excel/Functions/RefAndLookup/Filter.cs

@@ -14,6 +14,7 @@ Date               Author                       Change
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using OfficeOpenXml.Export.HtmlExport;
 using OfficeOpenXml.FormulaParsing.Excel.Functions.MathFunctions;
 using OfficeOpenXml.FormulaParsing.Excel.Functions.Metadata;
 using OfficeOpenXml.FormulaParsing.Exceptions;
@@ -184,5 +185,14 @@ public override string NamespacePrefix
 		/// If the function is allowed in a pivot table calculated field
 		/// </summary>
 		public override bool IsAllowedInCalculatedPivotTableField => false;
-	}
+
+        public override ExcelFunctionParametersInfo ParametersInfo => new ExcelFunctionParametersInfo(new Func<int, FunctionParameterInformation>((argumentIndex) =>
+        {
+            if (argumentIndex == 2)
+            {
+                return FunctionParameterInformation.IgnoreErrorInPreExecute;
+            }
+            return FunctionParameterInformation.Normal;
+        }));
+    }
 }

src/EPPlusTest/FormulaParsing/Excel/Functions/RefAndLookup/FilterTests.cs

@@ -67,5 +67,21 @@ public void ShouldFilterOnColumn()
             Assert.AreEqual(4, _ws.Cells["D2"].Value);
             Assert.AreEqual(1, _ws.Cells["D3"].Value);
         }
+
+        [TestMethod]
+        public void FilterShouldHandleNAAsIfEmptyValue()
+        {
+            using (var package = new ExcelPackage())
+            {
+                var s = package.Workbook.Worksheets.Add("test");
+                s.Cells["A1"].Value = "Joe";
+                s.Cells["A2"].Value = "Anna";
+                s.Cells["B1"].Value = 1;
+                s.Cells["B2"].Value = 2;
+                s.Cells["C1"].Formula = "FILTER(A1:A2, B1:B2 =1, NA())";
+                s.Calculate();
+                Assert.AreEqual("Joe", s.Cells["C1"].Value);
+            }
+        }
     }
 }