用vb控件做计算器，要求文本框底色为黄色

Const LineSpace As Integer = 100
Private theReg As Double
Private TextChange As Boolean
Private Operator As String

Private Sub Form_Load()
Dim X1 As Integer
Dim Y1 As Integer
Dim X2 As Integer
Dim Y2 As Integer
Dim BtnWidth As Integer
Dim BtnHeight As Integer
Dim ptr As Integer
Caption = "计算器"
X1 = CmdNum(0).Left
Y1 = CmdNum(0).Top
BtnWidth = CmdNum(0).Width
BtnHeight = CmdNum(0).Height
X2 = X1 + BtnWidth * 3 + LineSpace * 5
Y2 = Y1

For ptr = 1 To 10
Load CmdNum(ptr)
CmdNum(ptr).Visible = True
Next ptr

For ptr = 0 To 10
Select Case ptr
Case 0
CmdNum(0).Caption = "0"
CmdNum(0).Top = Y1 + BtnHeight * 3 + LineSpace * 3
CmdNum(0).Left = X1
CmdNum(0).Width = 2 * BtnWidth + LineSpace
Case 1 To 9
CmdNum(ptr).Caption = CStr(ptr)
CmdNum(ptr).Top = Y1 + (2 - (ptr - 1) \ 3) * (BtnHeight + LineSp