Private Sub txtInterestRate_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtInterestRate.TextChanged
        Try
 
            If Me.txtInterestRate.Text.Length = 0 Then          'reads interest rate text box
                Me.errInput.SetError(Me.txtInterestRate, "Please Enter a valid value") 'if 0 gives error
 
            ElseIf Not IsNumeric(txtInterestRate.Text) Then     'checks input for numeric value
                Me.errInput.SetError(Me.txtInterestRate, "Please Enter a valid Numeric value") 'if non-numerics gives error
                Throw New Exception("Please enter a valid numeric value")
 
            ElseIf txtInterestRate.Text = 0 Then                'checks input for numeric value
                Me.errInput.SetError(Me.txtLoanAmount, "Please Enter a Non Zero valid Numeric value") 'if non-numerics gives error
                Throw New Exception("Please enter a valid Non Zero numeric value")
 
            End If
 
        Catch ex As Exception       'exception handeler for error input
            MsgBox(ex.Message)      'displays error
            Me.txtInterestRate.Text = ("")
        End Try
    End Sub

Private Sub cmdOk_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOk.Click
  ' Check empty text
 
  If Me.txtInterestRate.Text.Trim = "" Then
    MessageBox.Show("Please enter interest rate", _
      "Missing Information", _
      MessageBoxButtons.OK, _
      MessageBoxIcon.Warning)
    Me.txtInterestRate.Focus() ' Set focus to field if you want
  End If
 
End Sub

If Me.txtInterestRate.Text <> ""
  /// do all of your stuff
Else
  MessageBox.Show("Please enter interest rate", _
     "Missing Information", _
     MessageBoxButtons.OK, _
     MessageBoxIcon.Warning)
End If