Here is the code:
border = TryCast(radDateTimePicker1.DateTimePickerElement.Children(1), BorderPrimitive)
border.BoxStyle = Telerik.WinControls.BorderBoxStyle.FourBorders
border.TopColor = Color.Transparent
border.LeftColor = Color.Transparent
border.RightColor = Color.Transparent
border.BottomColor = Color.Green
You can use the following converter as well: VB Converter
In addition, this answer applies for the WinForms suite.
Please do not hesitate to contact us with any additional questions or concerns.
Telerik by Progress
Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms.For more information check out this blog post
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