Conditional Formatting by Expression using EPPlus

Question

I\'m trying to format some range by using conditional Formatting feature of EPPlus. I read many document but there is nowhere mentions about Conditional Formatting Expressio

Answer 1

After many moons I found way more flexible and fast approach to do this using LINQ and EPPlus. All you need to do is: add extra property to your list to save Excel Row Numbers, and then retrieve cell addresses using LINQ. In this case it would look like this:

string sRng = string.Join(",", YourModel.Where(f => f.YourField == null)
    .Select(a => "H" + a.iRow + ",L" + a.iRow + ",AA" + a.iRow)); // this address could be many pages and it works

if (sRng.Length > 0) {
    ws.Cells[sRng].Style.Fill.BackgroundColor.SetColor(System.Drawing.Color.Green); 
}

Here is the full article:

https://www.codeproject.com/Tips/1231992/Conditional-Formatting-in-Excel-with-LINQ-and-EPPl

Also see here another example: https://stackoverflow.com/a/49022692/8216122 hope this helps somebody in the future.

Answer 2

I have found out solution by myself. Please take an example code:

ExcelAddress _formatRangeAddress = new ExcelAddress("B3:B10,D3:D10,F3:F10,H3:H10:J3:J10");
// fill WHITE color if previous cell or current cell is BLANK:
// B3 is the current cell because the range _formatRangeAddress starts from B3.
// OFFSET(B3,0,-1) returns the previous cell's value. It's excel function.
string _statement = "IF(OR(ISBLANK(OFFSET(B3,0,-1)),ISBLANK(B3)),1,0)";
var _cond4 = sheet.ConditionalFormatting.AddExpression(_formatRangeAddress);
_cond4.Style.Fill.PatternType = OfficeOpenXml.Style.ExcelFillStyle.Solid;
_cond4.Style.Fill.BackgroundColor.Color = Color.White;
_cond4.Formula = _statement;

// fill GREEN color if value of the current cell is greater than 
//    or equals to value of the previous cell
_statement = "IF(OFFSET(B3,0,-1)-B3<=0,1,0)";
var _cond1 = sheet.ConditionalFormatting.AddExpression(_formatRangeAddress);
_cond1.Style.Fill.PatternType = OfficeOpenXml.Style.ExcelFillStyle.Solid;
_cond1.Style.Fill.BackgroundColor.Color = Color.Green;
_cond1.Formula = _statement;

// fill RED color if value of the current cell is less than 
//    value of the previous cell
_statement = "IF(OFFSET(B3,0,-1)-B3>0,1,0)";
var _cond3 = sheet.ConditionalFormatting.AddExpression(_formatRangeAddress);
_cond3.Style.Fill.PatternType = OfficeOpenXml.Style.ExcelFillStyle.Solid;
_cond3.Style.Fill.BackgroundColor.Color = Color.Red;
_cond3.Formula = _statement;

In the above example,

• _formatRangeAddress is the range that will be applied for the conditional formatting by the expression. The first cell in this range will be used in the condition formula. (B3).
• _statement is the formula used to calculate the condition, this string doesn't start with equal sign (=) (difference point from MS Excel), the cell which is used to make expression is the first cell in the _formatRangeAddress. (B3).

Hope this is helpful to others who need. -Han-

Answer 3

There is support for conditional formatting in the 3.1 beta version of EPPlus.

Take a look at the source-code here: http://epplus.codeplex.com/discussions/348196/