# Processing Decimal Columns as Double when Importing a DataTable into a Workbook using RadSpreadProcessing

## Environment

| Version     | Product             | Author                                                                          |
| ----------- | ------------------- | ------------------------------------------------------------------------------- |
| 2025.4.1104 | RadSpreadProcessing | [Desislava Yordanova](https://www.telerik.com/blogs/author/desislava-yordanova) |

## Description

When importing a `DataTable` into a worksheet using [RadSpreadProcessing](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/overview), columns defined as `decimal` appear as text instead of numeric values. The import functionality checks whether the data type is primitive and only interprets primitive types as numeric. Primitive types narrow to CLR primitives (`sbyte`, `byte`, `short`, `ushort`, `int`, `uint`, `long`, `ulong`, `float`, `double`, `char`, `IntPtr`, `UIntPtr`, `bool`). Because `decimal` is not a primitive type, the library treats it as text.

This article also answers the following questions:

* How to convert decimal columns to double for proper import in Telerik Document Processing?
* How to ensure numeric semantics for decimal columns in SpreadProcessing?
* How to fix dataset column type issues in Telerik Document Processing SpreadProcessing?

## Solution

To process `decimal` columns as numeric values, clone the `DataTable`, change the column type from `decimal` to `double`, and import the modified table:

1. Clone the original `DataTable`.
2. Update the column type for `decimal` columns to `double`.
3. Import the cloned table into the worksheet using the [DataTableFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/formats-and-conversion/data-table/using-data-table-format-provider).

The following example demonstrates the full implementation:

```csharp
using Telerik.Windows.Documents.Spreadsheet.Model;
using Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx;
using Telerik.Windows.Documents.Spreadsheet.FormatProviders.DataTable;

static void Main(string[] args)
{
    // Create the original DataTable
    DataTable table = new DataTable("SampleTable");
    table.Columns.Add("Id", typeof(decimal));          // numeric column
    table.Columns.Add("Name", typeof(string));         // text column
    table.Columns.Add("Price", typeof(decimal));       // numeric column
    table.Columns.Add("Category", typeof(string));     // text column
    table.Rows.Add(1, "Laptop", 1299.99, "Electronics");
    table.Rows.Add(2, "Desk Chair", 199.50, "Furniture");
    table.Rows.Add(3, "Notebook", 4.25, "Stationery");

    // Clone the table and update column types
    DataTable clonedTable = table.Clone();
    foreach (DataColumn column in clonedTable.Columns)
    {
        if (column.DataType == typeof(decimal))
            column.DataType = typeof(double);
    }
    foreach (DataRow row in table.Rows)
    {
        clonedTable.ImportRow(row);
    }

    // Import the cloned DataTable
    DataTableFormatProvider provider = new DataTableFormatProvider();
    provider.ImportSettings.ShouldImportColumnHeaders = true;
    Workbook workbook = provider.Import(clonedTable);

    // Save the workbook to an XLSX file
    string filePath = Path.Combine(Path.GetTempPath(), "ProcessedData.xlsx");
    XlsxFormatProvider fileFormatProvider = new XlsxFormatProvider();
    using (FileStream fs = new FileStream(filePath, FileMode.Create, FileAccess.Write))
    {
        fileFormatProvider.Export(workbook, fs);
    }
}
```

### Key Notes

* The `DataTable.Clone()` method creates a copy of the schema. This allows you to modify column types without affecting the original data.
* Changing the column type ensures numeric semantics for `decimal` values during import.
* Use the `DataTableFormatProvider` to simplify the import process.

## See Also

* [Telerik Document Processing SpreadProcessing Overview](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/overview)
* [DataTableFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/formats-and-conversion/data-table/using-data-table-format-provider)