如何在FileUpload选择文件时显示ASP按钮 [英] How to show an ASP Button only when FileUpload has file chosen

问题描述

我想知道如何实现以下目标：



Show（隐藏在页面加载后面的代码）一个ASP按钮，当FileUpload ASP控件有一个文件被选中。



aspx

Hi,

I would like to know how to achieve the following:

Show (hidden with code behind on page load) an ASP Button, when the FileUpload ASP control has a file selected.

aspx

<asp:FileUpload ID="FileUpload1" runat="server" onchange="showButton()"/>
                       <p><asp:Button ID="Button1" runat="server"  Text="Upload File" />&nbsp;</p>

当FileUpload1有选择onchange的文件应该点亮

（按钮1保持隐藏且不显示）



Javascript：

When FileUpload1 has a file selected the onchange should fire
(Button 1 stays hidden and does not show)

Javascript:

<script type ="text/javascript" >
          function showButton() {
              document.getElementById('<%=Button1.ClientID%>').style.visibility = "visible";
          }
</script>

但这不起作用。



请让我知道我做错了什么。



（应该Button1.Visible = true;在代码隐藏中使用，如果是这样，你怎么在aspx文件中告诉它这样做？）

but this does not work.

Please let me know what I am doing wrong.

(should Button1.Visible=true; be used in codebehind instead, if so , how in the aspx file do you tell it to do so?)

推荐答案

试试这个

Try this

<asp:fileupload id="fileupload1" runat="server" onchange="showButton()" xmlns:asp="#unknown" />
<asp:button id="btnUpload" runat="server" text="Upload" style="display:none" xmlns:asp="#unknown" />

<script type ="text/javascript" >
        function showButton() {
            document.getElementById("<%=btnUpload.ClientID%>").style.display = "";
        }
    </script>

使用



如果（FileUpload1.hasfile == true）

{



//你的陈述///////////// /

}

Use

if (FileUpload1.hasfile==true)
{

// Your Statement//////////////
}

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