TextEdit.CustomMask Event

Occurs after the editor is initialized, got the focus, or the editor’s value is changed.

Namespace: DevExpress.Xpf.Editors

Assembly: DevExpress.Xpf.Core.v25.1.dll

NuGet Package: DevExpress.Wpf.Core

Declaration

C#

public event EventHandler<CustomMaskEventArgs> CustomMask

VB.NET

Public Event CustomMask As EventHandler(Of CustomMaskEventArgs)

Event Data

The CustomMask event's data class is CustomMaskEventArgs. The following properties provide information specific to this event:

Property	Description
ActionType	Gets the user action.
CurrentCursorPosition	Gets the cursor (caret) position before a user performs an action.
CurrentEditText	Gets text displayed in the editor before a user performs an action.
CurrentHead	Gets the editor’s text that precedes the cursor (caret) position or selected text.
CurrentSelectedText	Gets the editor’s selected text.
CurrentSelectionAnchor	Gets the selection start point before a user performs an action.
CurrentSelectionEnd	Gets the position of the right-most selected character.
CurrentSelectionStart	Gets the position of the left-most selected character.
CurrentTail	Gets the editor’s text that follows the cursor (caret) position or selected text.
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
InsertedText	Gets text a user attempts to add to the editor.
IsCanceled	Gets whether the user action does not lead to the editor value change.
IsSelection	Gets whether the editor contains selected text.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
ResultCursorPosition	Gets the cursor (caret) position after a user performs an action.
ResultEditText	Gets text displayed in the editor after a user performs an action.
ResultSelectionAnchor	Gets the selection start point after a user performs an action.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
Tag	Gets the editor’s Tag property value.

The event data class exposes the following methods:

Method	Description
Cancel()	Cancels the user action.
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.
SetResult(String, Int32, Nullable<Int32>)	Sets the editor text, cursor position, and selection anchor.
SetResult(String, String)	Sets the editor text and cursor position.
ToString()	Gets the transcript of the user’s action in the following format: (InitialState)->UserAction->(FinalState).

Remarks

You can use custom masks to process user input and specify complex custom conditions. Do the following to specify a custom mask:

1. Set the editor’s MaskType property to Custom.
2. Handle the CustomMask event.
3. Process the text displayed in the editor (e.CurrentEditText), the text entered by a user (e.InsertedText), or the edited text (e.ResultEditText).
4. Use e.SetResult or e.Cancel methods to specify the editor’s final text.

The following code sample allows users to enter only valid image file names:

XAML

<dxe:TextEdit MaskType="Custom" CustomMask="OnCustomMask"/>

C#

void OnCustomMask(object sender, DevExpress.Xpf.Editors.CustomMaskEventArgs e) {
    var imageExtensions = new string[] {".jpeg", ".jpg", ".png", ".gif", ".tiff", ".tif", ".bmp", ".svg", ".esp"};
    var enteredExtension = Path.GetExtension(e.ResultEditText);

    if (e.ResultEditText.Any(x => Path.GetInvalidFileNameChars().Contains(x)))
        e.Cancel();

    if (!imageExtensions.Any(x => x.StartsWith(enteredExtension, System.StringComparison.OrdinalIgnoreCase)))
        e.Cancel();
}

VB.NET

Private Sub OnCustomMask(ByVal sender As Object, ByVal e As DevExpress.Xpf.Editors.CustomMaskEventArgs)
    Dim imageExtensions = New String() {".jpeg", ".jpg", ".png", ".gif", ".tiff", ".tif", ".bmp", ".svg", ".esp"}
    Dim enteredExtension = Path.GetExtension(e.ResultEditText)

    If e.ResultEditText.Any(Function(x) Path.GetInvalidFileNameChars().Contains(x)) Then e.Cancel()

    If Not imageExtensions.Any(Function(x) x.StartsWith(enteredExtension, System.StringComparison.OrdinalIgnoreCase)) Then e.Cancel()
End Sub

Refer to the following help topic for more information: Mask Type: Custom.