c# - 检查asp:fileupload是否为空，客户端验证

Question

我在表单视图中有一个文件上传控件。如果没有上传文件，我希望它会导致验证错误。我可以在上面应用某种验证器还是让控件本身抛出验证错误？

Answer 1

<asp:FileUpload ID="FileUpload1" runat="server" />
 <asp:RequiredFieldValidator ID="RequiredFieldValidator1"
    runat="server" ErrorMessage="your own error message" 
    ControlToValidate="FileUpload1"></asp:RequiredFieldValidator>

Answer 2

要检查文件上传是否有文件，请像这样使用 jquery

    $(document).ready(function(){
        $('#button').click(function(){
          if($('#uploadFile').val()=="")
           {
           alert("no file selected!");
           return false;
          }
        });
    });

Answer 3

尝试类似的东西

<asp:FileUpload ID="fu1" runat="server" />
<asp:Button ID="btn" runat="server" CausesValidation="true" Text="Click" 
       OnClientClick="return ValidateFileName();" /> 

 <script type="text/javascript">
function ValidateFileName() {
    var fu = document.getElementById("<%= fu1.ClientID %>");
    var f = fu.value + "";
    if ((f.indexOf("#", 0) >= 0) || (f.indexOf("$", 0) >= 0) ||
          (f.indexOf("%", 0) >= 0) || (f.indexOf("^", 0) >= 0)) {
        alert("Filename: [" + f + "] contains invalid char");
        return false;//will stop button click event here
    }

    return true;
}