[5分]文本框多次输入数据，如何不覆盖上一次的数据，而是连续显示

Private Sub 工序列表框_DblClick(Cancel As Integer)
Dim i As Long
Dim str As String
For i = 0 To Me.工序列表框.ListCount
    If Me.工序列表框.Selected(i) = True Then
           str = str & Me.工序列表框.Column(0, i) & Me.工序列表框.Column(1, i) & ";"
    End If
Next
Me.车间.Value = Me.车间.Value & str
End Sub