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/Delete/DeleteFewWorksheets.cs

@@ -0,0 +1,41 @@
+using System.IO;
+using ClosedXML.Excel;
+
+namespace ClosedXML_Examples.Delete
+{
+    public class DeleteFewWorksheets:IXLExample
+    {
+        public void Create(string filePath)
+        {
+            string tempFile = ExampleHelper.GetTempFilePath(filePath);
+            try
+            {
+                //Note: Prepare
+                {
+                    var workbook = new XLWorkbook();
+                    workbook.Worksheets.Add("1");
+                    workbook.Worksheets.Add("2");
+                    workbook.Worksheets.Add("3");
+                    workbook.Worksheets.Add("4");
+                    workbook.SaveAs(tempFile);
+                }
+
+                //Note: Delate few worksheet
+                {
+                    var workbook = new XLWorkbook(tempFile);
+                    workbook.Worksheets.Delete("1");
+                    workbook.Worksheets.Delete("2");
+                    workbook.SaveAs(filePath);
+                }
+            }
+            finally
+            {
+                if (File.Exists(tempFile))
+                {
+                    File.Delete(tempFile);
+                }
+            }
+            
+        }
+    }
+}