Fix DecimalConverter to support scientific notation

- Changed NumberStyles from Number to Float | AllowThousands
- This enables parsing of scientific notation values (e.g., 1.2345678E5)
- Aligns DecimalConverter with SingleConverter and DoubleConverter behavior
- Added comprehensive tests for scientific notation parsing

Fixes #35

Co-authored-by: Chrissy LeMaire <[email protected]>

Author: github-actions[bot]

project/dbatools.Tests/Csv/TypeConverterTest.cs

@@ -161,6 +161,26 @@ public void TestDecimalConverter()
             Assert.AreEqual(1234567890.123456m, result);
         }
 
+        [TestMethod]
+        public void TestDecimalConverterScientificNotation()
+        {
+            var converter = DecimalConverter.Default;
+
+            // Test case from issue #35
+            Assert.IsTrue(converter.TryConvert("1.2345678E5", out decimal result));
+            Assert.AreEqual(123456.78m, result);
+
+            // Additional scientific notation tests
+            Assert.IsTrue(converter.TryConvert("1.5e10", out result));
+            Assert.AreEqual(15000000000m, result);
+
+            Assert.IsTrue(converter.TryConvert("2.5E-3", out result));
+            Assert.AreEqual(0.0025m, result);
+
+            Assert.IsTrue(converter.TryConvert("-3.14E2", out result));
+            Assert.AreEqual(-314m, result);
+        }
+
         #endregion
 
         #region Type Converter Registry Tests

project/dbatools/Csv/TypeConverters/NumericConverters.cs

@@ -135,7 +135,7 @@ protected override bool TryParseSpan(ReadOnlySpan<char> value, NumberStyles styl
 
     /// <summary>
     /// Converts string values to Decimal values.
-    /// Supports culture-aware parsing for decimal separators.
+    /// Supports culture-aware parsing for decimal separators and scientific notation.
     /// Addresses LumenWorks issue #66 for Czech locale decimal parsing.
     /// </summary>
     public sealed class DecimalConverter : CultureAwareConverterBase<decimal>
@@ -146,7 +146,7 @@ public sealed class DecimalConverter : CultureAwareConverterBase<decimal>
         /// <summary>Initializes a new instance of the <see cref="DecimalConverter"/> class.</summary>
         public DecimalConverter()
         {
-            NumberStyles = NumberStyles.Number;
+            NumberStyles = NumberStyles.Float | NumberStyles.AllowThousands;
         }
 
         /// <inheritdoc />