看不懂,帮我解析!!!

Sub subGetAllData()
Dim StrSql As String
Dim RstTblUnit As New ADODB.Recordset
Dim Xitem As ListItem
StrSql = ""
StrSql = "select * from TblUnit"

Set RstTblUnit = conn.Execute(StrSql)
LvwUnitName.ListItems.Clear

If Not RstTblUnit.EOF Then
RstTblUnit.MoveFirst
While Not RstTblUnit.EOF
DoEvents
Set Xitem = LvwUnitName.ListItems.Add(Text:=RstTblUnit!ID)
Xitem.SubItems(1) = RstTblUnit!UnitName
RstTblUnit.MoveNext
Wend
End If
End Sub
上面的代码请大虾给我详细的解说一下,我是刚学的:

Dim Xitem As ListItem '这个定义什么类型
DoEvents '这个又是什么呀
Set Xitem = LvwUnitName.ListItems.Add(Text:=RstTblUnit!ID) '????
Xitem.SubItems(1) = RstTblUnit!UnitName '????