It seems that .NET does not support Indian formatting for some reason. You have to implement formatting yourself, for example write your own (overloaded) ToString method. Shouldn't be that hard to write code for this.

I did find a one .NET implementation for this (both numbers and dates Indian Number & Date format, but the source code is in C#.

Try this
Format(yourNo, "#,##0")
all the best

Try this :
Go to Control Panel >>>> Regional Options >>> Numbers and change the "Digit Grouping" like 12,34,56,789 then OK


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Label1.Text = Format(Your No., "##,##0")
End Sub