如何在aspxgridview编辑状态时获取控件？

[groundsky]

使用DEV aspxgridview控件

<dx:ASPxGridView ID="gridAttach" runat="server" AutoGenerateColumns="False" Caption="附件列表" ClientInstanceName="gridAttach" DataSourceID="SqlDataSource2" EnableTheming="True" KeyFieldName="id" Theme="Aqua" Width="912px">
        <EditFormLayoutProperties ColCount="2">
            <Items>
                <dx:GridViewColumnLayoutItem ColSpan="2" ColumnName="附件名称">
                    <Template>
                        <dx:ASPxTextBox ID="txtattach" runat="server" Text='<%# Bind("附件名称") %>' Width="170px">
                        </dx:ASPxTextBox>
                        <dx:ASPxUploadControl ID="uploaderattach" runat="server" OnFileUploadComplete="uploaderattach_FileUploadComplete1" ShowUploadButton="True" UploadMode="Auto" Width="280px">
                        </dx:ASPxUploadControl>
                    </Template>
                </dx:GridViewColumnLayoutItem>
                <dx:GridViewColumnLayoutItem ColumnName="类别">
                </dx:GridViewColumnLayoutItem>
                <dx:GridViewColumnLayoutItem ColumnName="扩展名">
                </dx:GridViewColumnLayoutItem>
                <dx:GridViewColumnLayoutItem ColumnName="上传日期">
                </dx:GridViewColumnLayoutItem>
                <dx:GridViewColumnLayoutItem ColumnName="上传人">
                </dx:GridViewColumnLayoutItem>
                <dx:GridViewColumnLayoutItem ColSpan="2" ColumnName="备注" RowSpan="2">
                </dx:GridViewColumnLayoutItem>
                <dx:EditModeCommandLayoutItem ColSpan="2" HorizontalAlign="Right">
                </dx:EditModeCommandLayoutItem>
            </Items>
        </EditFormLayoutProperties>
        <Columns>
            <dx:GridViewCommandColumn ShowDeleteButton="True" ShowEditButton="True" ShowNewButtonInHeader="True" VisibleIndex="0">
            </dx:GridViewCommandColumn>
            <dx:GridViewDataTextColumn FieldName="id" ReadOnly="True" Visible="False" VisibleIndex="1">
                <EditFormSettings Visible="False" />
            </dx:GridViewDataTextColumn>
            <dx:GridViewDataTextColumn FieldName="sid" Visible="False" VisibleIndex="2">
            </dx:GridViewDataTextColumn>
            <dx:GridViewDataTextColumn FieldName="类别" VisibleIndex="3">
            </dx:GridViewDataTextColumn>
            <dx:GridViewDataTextColumn FieldName="附件名称" VisibleIndex="4">
            </dx:GridViewDataTextColumn>
            <dx:GridViewDataTextColumn FieldName="扩展名" VisibleIndex="5">
            </dx:GridViewDataTextColumn>
            <dx:GridViewDataDateColumn FieldName="上传日期" VisibleIndex="6">
            </dx:GridViewDataDateColumn>
            <dx:GridViewDataTextColumn FieldName="上传人" VisibleIndex="7">
            </dx:GridViewDataTextColumn>
            <dx:GridViewDataMemoColumn FieldName="备注" VisibleIndex="8">
            </dx:GridViewDataMemoColumn>
        </Columns>
<Styles AdaptiveDetailButtonWidth="22"></Styles>
    </dx:ASPxGridView>

后台代码：

 Protected Sub uploaderattach_FileUploadComplete1(sender As Object, e As FileUploadCompleteEventArgs)
        Dim newfile As String
        newfile = Help.AspxUploadHelper.GetNewFile(Server.MapPath("~/Uploadfiles/"), e.UploadedFile.FileName)
        e.UploadedFile.SaveAs(newfile)
        Me.hdNewfilename.Value = newfile
        e.CallbackData = newfile
        newfile = IO.Path.GetFileName(newfile)
        Dim col As New GridViewDataColumn
        col = Me.gridAttach.Columns("附件名称")
        'Me.gridAttach.GetRow(Me.gridAttach.FocusedRowIndex).FindControl("txtattach")
        DirectCast(Me.gridAttach.FindEditRowCellTemplateControl(col, "txtattach"), ASPxTextBox).Text = newfile
        DirectCast(Me.gridAttach.FindEditFormTemplateControl("txtattach"), ASPxTextBox).Text = newfile
        DirectCast(Me.gridAttach.FindEditFormLayoutItemTemplateControl("txtattach"), ASPxTextBox).Text = newfile

    End Sub

如上图，想上传文件后，将文件的名称写入到 txtattach控件中，但是一直无法获取到txtattach控件，红色代码内三种获取方式都试过了，获得的都是nothing ，求各位大侠帮帮忙。