# TextControl.OnFormFieldCheckChanged Method

> Raises the FormFieldCheckChanged event.

- **Product:** TX Text Control .NET for WPF
- **Section:** Reference
- **Kind:** Method
- **Introduced:** 28.0
- **Namespace:** `TXTextControl.WPF`
- **Package:** `TXTextControl.TextControl.WPF.SDK` (assembly `TXTextControl.WPF.dll`, from the private NuGet feed or Text Control Offline Packages)
- **.NET Framework:** reference `TXTextControl.WPF.dll` from the setup
- **Path:** TX Text Control .NET for WPF > Reference > TXTextControl.WPF > TextControl.OnFormFieldCheckChanged Method
- **540 words**
- **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/onformfieldcheckchanged-method/
- **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/onformfieldcheckchanged-method/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/onformfieldcheckchanged-method/llms-full.txt

---

### Description

Raises the FormFieldCheckChanged event.

### Syntax

```csharp
protected virtual void OnFormFieldCheckChanged(CheckFormFieldEventArgs e);
```

```vbnet
Protected Overridable Sub OnFormFieldCheckChanged(e As CheckFormFieldEventArgs)
```

### Parameters

| Parameter | Description |
|---|---|
| e | Specifies a [CheckFormFieldEventArgs](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/checkformfieldeventargs/llms-full.txt) object that contains the event data. |

### Examples

The following example extends Text Control and performs custom processing when On Form Field Check Changed is invoked.

```csharp
class CustomTextControl : TXTextControl.WPF.TextControl
{
    protected override void OnFormFieldCheckChanged(CheckFormFieldEventArgs e)
    {
        // Add custom processing before registered event handlers run.
        base.OnFormFieldCheckChanged(e);
    }
}
```

```vbnet
Class CustomTextControl
    Inherits TXTextControl.WPF.TextControl

    Protected Overrides Sub OnFormFieldCheckChanged(e As CheckFormFieldEventArgs)
        ' Add custom processing before registered event handlers run.
        MyBase.OnFormFieldCheckChanged(e)
    End Sub
End Class
```

---

## Nearby

- **Previous:** [TextControl.OnFormattingStyleListChanged Method](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/onformattingstylelistchanged-method/llms-full.txt)
- **Next:** [TextControl.OnFormFieldDateChanged Method](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/onformfielddatechanged-method/llms-full.txt)