# Using a Character Format Validator

Create a validator to check for specific characters and take action if the value is invalid. Use the CharFormatValidator class and CellStyleNotify to add the validator to a cell range.

## Content

You can create a validator that checks for specific characters.
A validation error occurs if the value is not valid. You can also create an action, such as adding a backcolor to the cell, that lets the user know the value is invalid.
Use the **CharFormatValidator** class to create the validator. Specify a notification type such as [CellStyleNotify](/spreadnet/api/latest/online-win/FarPoint.Win.Spread/FarPoint.Win.Spread.CellStyleNotify.html). Then use the [AddValidators](/spreadnet/api/latest/online-win/FarPoint.Win.Spread/FarPoint.Win.Spread.SheetView.AddValidators.html) method to add the validator to a cell range.
The following image displays an invalid backcolor for the cell.
![Spereadsheet cell displaying a blue backcolor for an invalid value](https://cdn.mescius.io/document-site-files/images/2238e618-a1fb-45a6-9ce5-9a4157bd2931/images/charvalid.png)

## Using Code

The following example displays an invalid backcolor if you type characters other than the format string.

```csharp
FarPoint.Win.Spread.CellStyleNotify cnotify = new FarPoint.Win.Spread.CellStyleNotify();
cnotify.InvalidCellStyle.BackColor = Color.Aqua;
FarPoint.Win.Spread.CharFormatValidator cFormatValidator1 = new FarPoint.Win.Spread.CharFormatValidator();
cFormatValidator1.Format = "Ａａ";
cFormatValidator1.Actions.Add(cnotify);
fpSpread1.Sheets[0].AddValidators(new FarPoint.Win.Spread.Model.CellRange(1, 1, 1, 1), cFormatValidator1);
```

```vbnet
Dim cnotify As New FarPoint.Win.Spread.CellStyleNotify()
cnotify.InvalidCellStyle.BackColor = Color.Aqua
Dim charFormatValidator1 As New FarPoint.Win.Spread.CharFormatValidator()
charFormatValidator1.Format = "Ａａ"
charFormatValidator1.Actions.Add(cnotify)
fpSpread1.Sheets(0).AddValidators(New FarPoint.Win.Spread.Model.CellRange(1, 1, 1, 1), charFormatValidator1)
```

## See Also

[Using a Cell Comparison Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellcomparevalidator)
[Using a String Comparison Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellcomparestring)
[Using a Value Comparison Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellcomparevalue)
[Using an Encoding Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellencodingvalid)
[Using the Exclude List Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellexcludevalidator)
[Using the Include List Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellincludevalidate)
[Using a Pair Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellpairvalidate)
[Using the Range Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellrangevalidator)
[Using a Regular Expression Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellregexpression)
[Using a Required Field Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellrequiredvalid)
[Using a Required Type Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellrequiretypev)
[Using a Surrogate Character Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-cellsurrogate)
[Using a Text Length Validator](/spreadnet/docs/latest/online-win/overview/spwin-devguide/spwin-interactcell/spwin-cellvalid/spwin-cellvalidation/spwin-celltextlvalid)