• $ cat "

    Programmatically Add Conditional Formatting Formula to a Cell in Excel

    "

    The following snippet demonstrates how to add a conditional formatting rule to a cell. The rule specifies that the cell color is set to red if the contents of the cell has a length in characters longer than 3.

    The snippet assumes an existing worksheet instance.

    var range = (Excel.Range)worksheet.Cells[rowNo + 2, colNo + 1];

    Excel.FormatCondition condition = (Excel.FormatCondition)range.FormatConditions.Add(
        Microsoft.Office.Interop.Excel.XlFormatConditionType.xlExpression, 
        Type.Missing, "=LEN(R[0]C[0])>3", Type.Missing, Type.Missing, 
        Type.Missing, Type.Missing, Type.Missing);
    

    condition.Interior.ColorIndex = 3; // Red