Initial commit of the ClosedXML library

Establishes the foundational structure, core Excel functionality, and tooling.

- Implements base components for cells, ranges, columns, and rows.
- Integrates a custom calculation engine with a wide range of Excel functions.
- Adds comprehensive support for styling, conditional formatting, data validation, comments, pictures, and charts.
- Configures build setup, project metadata (NuGet), and developer guidelines.
- Includes editor and Git attributes for consistent code style and line endings.

ClosedXML_Examples/Rows/RowCells.cs

@@ -0,0 +1,73 @@
+using System;
+using ClosedXML.Excel;
+
+
+namespace ClosedXML_Examples
+{
+    public class RowCells : IXLExample
+    {
+        #region Variables
+
+        // Public
+
+        // Private
+
+
+        #endregion
+
+        #region Properties
+
+        // Public
+
+        // Private
+
+        // Override
+
+
+        #endregion
+
+        #region Events
+
+        // Public
+
+        // Private
+
+        // Override
+
+
+        #endregion
+
+        #region Methods
+
+        // Public
+        public void Create(String filePath)
+        {
+            var workbook = new XLWorkbook();
+            var ws = workbook.Worksheets.Add("Row Cells");
+
+            var rowFromWorksheet = ws.Row(1);
+            rowFromWorksheet.Cell(1).Style.Fill.BackgroundColor = XLColor.Red;
+            rowFromWorksheet.Cells("2").Style.Fill.BackgroundColor = XLColor.Blue;
+            rowFromWorksheet.Cells("3,5:6").Style.Fill.BackgroundColor = XLColor.Red;
+            rowFromWorksheet.Cells(8, 9).Style.Fill.BackgroundColor = XLColor.Blue;
+
+            var rowFromRange = ws.Range("A2:I2").FirstRow();
+
+            rowFromRange.Cell(1).Style.Fill.BackgroundColor = XLColor.Red;
+            rowFromRange.Cells("2").Style.Fill.BackgroundColor = XLColor.Blue;
+            rowFromRange.Cells("3,5:6").Style.Fill.BackgroundColor = XLColor.Red;
+            rowFromRange.Cells(8, 9).Style.Fill.BackgroundColor = XLColor.Blue;
+
+            ws.Columns().Width = 7;
+
+            workbook.SaveAs(filePath);
+        }
+
+        // Private
+
+        // Override
+
+
+        #endregion
+    }
+}