Added new kb article preventing-cell-formatting-extension-spreadprocessing

knowledge-base/preventing-cell-formatting-extension-spreadprocessing.md

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+---
+title: Preventing Excel From Extending Cell Formatting Below Formatted Range Using SpreadProcessing
+description: Resolve the issue where cells below a formatted range inherit formatting when using SpreadProcessing to generate Excel files.
+type: how-to
+page_title: Avoiding Automatic Formatting Extension Below a Range in Excel with SpreadProcessing
+meta_title: Avoiding Automatic Formatting Extension Below a Range in Excel with SpreadProcessing
+slug: preventing-cell-formatting-extension-spreadprocessing
+tags: telerik-document-processing, spreadprocessing, excel-formatting, cell-formatting, worksheet
+res_type: kb
+ticketid: 1693269
+---
+
+## Environment
+
+ Version | Product | Author | 
+| ---- | ---- | ---- | 
+| 2025.2.520| RadSpreadProcessing |[Desislava Yordanova](https://www.telerik.com/blogs/author/desislava-yordanova)|
+
+## Description
+
+When exporting an Excel file using [SpreadProcessing](https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/overview) and applying formatting to a range of cells, entering data immediately below the formatted range may cause Excel to automatically extend the formatting. This occurs due to Excel's built-in "Extend data range formats and formulas" feature. The behavior is controlled by Excel itself and cannot be disabled programmatically from within the SpreadProcessing library.
+
+Clearing the formatting of cells in a range below the formatted data helps mitigate this issue. However, this approach works only for pre-defined ranges and does not override Excel's internal settings permanently.
+
+## Solution
+
+To prevent Excel's automatic formatting extension, clear the formatting of cells in a specified range below the formatted and populated range. Use the following steps and code:
+
+1. Identify the used cell range in the worksheet.
+2. Define a range below the used cells that you want to clear formatting from.
+3. Apply default formatting (e.g., transparent fill, no borders, default alignment, etc.) to the defined range.
+
+Use the following code example:
+
+```csharp
+// Identify the used range in the worksheet
+CellRange usedCellRange = worksheet.UsedCellRange;
+int rowIndexStart = usedCellRange.ToIndex.RowIndex + 1;
+int columnIndexStart = usedCellRange.FromIndex.ColumnIndex + 1;
+int rowIndexEnd = rowIndexStart + 10; // Adjust the range size as needed
+int columnIndexEnd = usedCellRange.ToIndex.ColumnIndex;
+
+// Define the range to clear formatting
+CellRange clearRange = new CellRange(rowIndexStart, columnIndexStart, rowIndexEnd, columnIndexEnd);
+
+// Set transparent fill and default formatting
+var clearColor = Colors.Transparent;
+SetDefaultFormattingCellRange(worksheet, clearRange, clearColor);
+
+// Helper method to apply default formatting
+static void SetDefaultFormattingCellRange(Worksheet worksheet, CellRange cellRange, Color cellColor)
+{
+    worksheet.Cells[cellRange].SetFill(new PatternFill(PatternType.Solid, cellColor, Colors.Transparent));
+    worksheet.Cells[cellRange].SetIsBold(false);
+    worksheet.Cells[cellRange].SetHorizontalAlignment(RadHorizontalAlignment.Left);
+    worksheet.Cells[cellRange].SetVerticalAlignment(RadVerticalAlignment.Center);
+    worksheet.Cells[cellRange].SetIsWrapped(false);
+    worksheet.Cells[cellRange].SetValue(string.Empty);
+
+    CellBorder border = new CellBorder(CellBorderStyle.Thin, ThemableColor.FromColor(Colors.LightGray));
+    CellBorder noBorder = new CellBorder(CellBorderStyle.None, ThemableColor.FromColor(Colors.Black));
+
+    worksheet.Cells[cellRange].SetBorders(new CellBorders(
+        left: border,
+        top: border,
+        right: border,
+        bottom: border,
+        diagonalUp: noBorder,
+        diagonalDown: noBorder,
+        insideHorizontal: border,
+        insideVertical: border)
+    );
+}
+```
+
+This approach minimizes the chances of Excel automatically extending formatting when new data is entered below the formatted range.
+
+## See Also
+
+- [SpreadProcessing Overview](https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/overview)
+- [Working with Cell Formats](https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/formats)
+- [Working with Worksheets in SpreadProcessing](https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/worksheets)