Hi Barry,
Thank you for your interest in Syncfusion Products.
We have two specific TextBox controls to display numeric values alone. They are IntegerTextBox and DoubleTextBox. The IntegerTextBox is derived from a Windows Forms framework text box control and can display integer data type values alone.The DoubleTextBox is a text box-derived control that can display double data type values. Please refer the below sample that llustrates this:
http://websamples.syncfusion.com/samples/Tools.Windows/46651/main.htmPlease let me know if any concerns.
Regards,
Fathima