Upload multiple files to database in ASP.Net

Hi, I have a question about uploading multiple files using vb.net. I can select one file only to upload but need to save first before I can proceed to the next upload file. The reason I want to upload multiple because before I select the file, I need to insert the account no which is the unique id (cannot duplicate). So, my solution is upload multiple file at the same time by using same account no.

after I uploaded multiple files and check the database then only show 1 file save.

<tr>
    <td>
        <asp:DropDownList ID="ddl_bnkName" CssClass="form-control input-sm" runat="server"></asp:DropDownList>
        <asp:HiddenField ID="hfaccno_id" runat="server" />
    </td>

    <td><asp:TextBox ID="bnkAcct" CssClass="form-control input-sm" runat="server"></asp:TextBox></td>
    <td><asp:FileUpload ID="upl_bnkDocs" CssClass="form-control input-sm" runat="server" /></td>
    
    <td><asp:Button ID="btn_bnkAdd" OnClick="btn_bnkAdd_Click" CssClass="btn btn-sm btn-primary" runat="server" Text="Add" /></td>
</tr>

vb code : 

Protected Sub btn_bnkAdd_Click(sender As Object, e As EventArgs)
        If Not retrievePerson.Value = "" Then
            If ddl_bnkName.SelectedValue <> 0 Then
                If bnkAcct.Text <> Nothing Then
                    Dim aDM As New PersonDM
                    aDM.assgnby = Session("UserID")
                    aDM.per_id = retrievePerson.Value
                    aDM.acc_no = bnkAcct.Text
                    aDM.branch_cd = Session("BranchID")
                    aDM.bank_id = ddl_bnkName.SelectedItem.Value
                    Dim path As String = UploadDocument(upl_bnkDocs, aDM.per_id, aDM.acc_no, ddl_bnkName.SelectedItem.Text)
                    aDM.doc_path = path
                    Dim bnkadSucc = PersonDB.InsertCIFAccNo(aDM)
                    If bnkadSucc.accno_id = 0 Then
                        UtilClass.AlertMessageStartupScripts(Me, "Bank account is already exists")
                    End If
                    PopulateRPTBnkAcctList()
                    ClearBankInfo()
                Else
                    UtilClass.AlertMessageStartupScripts(Me, "Please insert account no")
                End If
            Else
                UtilClass.AlertMessageStartupScripts(Me, "Please Select Bank")
            End If
        Else
            UtilClass.AlertMessageStartupScripts(Me, "No Person ID")
        End If
    End Sub

upload script :

Private Function UploadDocument(ByVal upRpt As FileUpload, ByVal per_id As String, ByVal acct_no As String, ByVal bnk_name As String) As String

        Dim retPath As String = Nothing

        Dim PathToSave As String = UtilFolderAccess.CreateOutputFolderBank(per_id, "BANK_ACCNO")
        Dim ext As String = System.IO.Path.GetExtension(upRpt.PostedFile.FileName)
        Dim fileName As String = acct_no & "_" & bnk_name & ext
        'Dim FromFolder As String = System.IO.Path.GetDirectoryName(upRpt.PostedFile.FileName)

        If upRpt.HasFile = True Then

            If (System.IO.File.Exists(PathToSave & "\" & fileName)) = True Then
                UtilClass.AlertMessageStartupScripts(Me, "A file with the same name already exists.")
                retPath = Nothing
            Else
                'CopyFile(FromFolder, PathToSave & "\" & fileName)
                Try
                    upRpt.SaveAs(PathToSave & "\" & fileName)
                    retPath = PathToSave & "\" & fileName
                Catch ex As Exception
                    retPath = Nothing
                End Try

            End If
        End If

        Return retPath
    End Function

So, here how to edit the code for that solution? Kindly help me. Appreciated if someone can help me. TQ