It is a very simple coding for entering numeric value in a text box (VB.NET)

Step1 : Place a TextBox(TextBox1) on your form.

Step2 : Create a function (say TrapKey) for Checking the Values entered.

Step3: Call this function in the KeyPress event of TextBox1.

This has been explained below:

Code:
Private Function TrapKey(ByVal KCode As String) As Boolean

If (KCode >= 48 And KCode <= 57) Or KCode = 8 Then 

'The AsCII values for numbers are between 48 to 57 and ASCII value 8 is for BackSpace.

TrapKey = False

Else

TrapKey = True

End If

End Function

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

e.Handled = TrapKey(Asc(e.KeyChar))

End Sub