求救asp高手，帮我解释下如下代码，在线等，急！

SqlHelper.FillDataset(Application("connectstring"), CommandType.StoredProcedure, "SELECTCOMPANY_DEPARTMENT", ds, New String() {"subcompany"})

            SqlHelper.FillDataset(Application("connectstring"), CommandType.StoredProcedure, "SELECTALLDEPARTMENT_DEPARTMENT", ds, New String() {"department"})

           

         
    Sub search()

        Dim strSubcompany, strDepartment, strFindname As String

        strSubcompany = Trim(subcompany.SelectedItem.Text)

        strDepartment = Trim(department.SelectedItem.Text)

        strFindname = Trim(findname.Text)

        If strSubcompany = "请选择..." Then
            strSubcompany = "%"
        End If

        If strDepartment = "请选择..." Then
            strDepartment = "%"
        End If

        If strFindname = "" Then
            strFindname = "%"
        End If
        Dim objReader As SqlClient.SqlDataReader
        Try

            Dim subcompanyParm As SqlParameter = New SqlParameter("@subcompany", SqlDbType.NVarChar, 50)
            subcompanyParm.Value = strSubcompany

            Dim departmentParm As SqlParameter = New SqlParameter("@department", SqlDbType.NVarChar, 50)
            departmentParm.Value = strDepartment

            Dim realnameParm As SqlParameter = New SqlParameter("@realname", SqlDbType.NVarChar, 50)
            realnameParm.Value = strFindname

            objReader = SqlHelper.ExecuteReader(Application("connectstring"), CommandType.StoredProcedure, "SEARCH_STAFF", subcompanyParm, departmentParm, realnameParm)

            Repeater1.DataSource = objReader
            Repeater1.DataBind()
        Catch exc As Exception
            Session("wrong") = "不能正确获取用户资料！" + exc.Message
            Session("returnURL") = "../document_address.aspx"
            Response.Redirect("frame/wrong.aspx")
        Finally
            objReader.Close()
        End Try
    End Sub

    Private Sub subcompany_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles subcompany.SelectedIndexChanged

        Dim ds As DataSet
        ds = New DataSet
        Dim i As Integer

        Dim subcompanyParm As SqlParameter = New SqlParameter("@subcompany", SqlDbType.NVarChar, 50)
        subcompanyParm.Value = Trim(subcompany.SelectedItem.Text)

        SqlHelper.FillDataset(Application("connectstring"), CommandType.StoredProcedure, "SELECTBYCOMPANY_DEPARTMENT", ds, New String() {"department"}, subcompanyParm)
        Dim strDepartment() As String
        strDepartment = New String() {}

        If ds.Tables("department").Rows.Count > 0 Then

            ReDim Preserve strDepartment(0)
            strDepartment(0) = "请选择..."

            For i = 1 To ds.Tables("department").Rows.Count
                ReDim Preserve strDepartment(i)
                strDepartment(i) = ds.Tables("department").Rows(i - 1)("departmentname")
            Next
        Else

            ReDim Preserve strDepartment(0)
            strDepartment(0) = "请选择..."
        End If

        department.DataSource = strDepartment
        department.DataBind()
    End Sub
End Class