【VB开源代码栏目提醒】：网学会员在VB开源代码频道为大家收集整理了Ex5_10.frm提供大家参考，希望对大家有所帮助!

    VERSION 5.00
    Begin VB.Form Ex5_10 
       Caption         =   "Form1"
       ClientHeight    =   2250
       ClientLeft      =   60
       ClientTop       =   450
       ClientWidth     =   3375
       LinkTopic       =   "Form1"
       ScaleHeight     =   2250
       ScaleWidth      =   3375
       StartUpPosition =   3  '窗口缺省
       Begin VB.CommandButton Command1 
          Caption         =   "显示"
          Height          =   375
          Left            =   840
          TabIndex        =   4
          Top             =   1560
          Width           =   1095
       End
       Begin VB.TextBox Text2 
          Height          =   375
          Left            =   1560
          TabIndex        =   3
          Top             =   960
          Width           =   1455
       End
       Begin VB.TextBox Text1 
          Height          =   375
          Left            =   1560
          TabIndex        =   1
          Top             =   240
          Width           =   1455
       End
       Begin VB.Label Label2 
          Caption         =   "第二个参数"
          Height          =   255
          Left            =   480
          TabIndex        =   2
          Top             =   1080
          Width           =   975
       End
       Begin VB.Label Label1 
          Caption         =   "第一个参数"
          Height          =   255
          Left            =   480
          TabIndex        =   0
          Top             =   360
          Width           =   975
       End
    End
    Attribute VB_Name = "Ex5_10"
    Attribute VB_GlobalNameSpace = False
    Attribute VB_Creatable = False
    Attribute VB_PredeclaredId = True
    Attribute VB_Exposed = False
    Sub mysum(var1 As String, Optional var2 As Integer = 10)
        '给可选参数设定默认值
        Text1.Text = var1
        Text2.Text = var2
    End Sub
    Private Sub Command1_Click()
        Call mysum("abcd")
    End Sub