input file实现多张图片上传

网上找的.

注意：页面上初始的file控件必须有runat="server"标志。也就是说，这个页面上必须至少有一个runat="server"的file控件，否则后台接收不到Request.Files。
<FORM id="form1" runat="server">
            <DIV id="div1">
                <INPUT ID="File1" TYPE="file" NAME="File1" runat="server">
                <INPUT TYPE="button" VALUE="添加附件" onclick="javascript:AddFile();">
                <INPUT TYPE="button" VALUE="删除附件" onclick="javascript:RemoveFile();">
                <ASP:LISTBOX id="ListBox1" Width="200px" Height="100px" runat="server"> </ASP:LISTBOX>
                <ASP:BUTTON id="Button1" runat="server" Text="保存" Width="60px"> </ASP:BUTTON>
            </DIV>
            <ASP:LITERAL ID="lResult" Runat="server"> </ASP:LITERAL>
           
        </FORM>

<SCRIPT language="javascript">
<!--
function AddFile()
{   
 
    var file = document.getElementById("div1").firstChild;
    if(file.value == "")
    {
        alert("请选择文件!");
        return;
    }
   
    var ary = file.value.split("\");
    var filename = ary[ary.length-1];
   
    var bAddFile = true;
    if(CheckOptionsExists(filename,document.getElementById("ListBox1")))
    {
       
        alert("文件已经存在列表中!");
        div1.removeChild(file);
        bAddFile = false;
       
    }
   
   
    var f = document.createElement("input");
    f.type = "file";
    f.name = "file"
   
    div1.insertBefore(f,div1.firstChild);
   
    if(!bAddFile)
    {
        return
    }
    var o = new Option();
    o.innerText = filename;
    o.value = file.uniqueID;
    document.getElementById("ListBox1").appendChild(o);
   
    file.style.display = "none";
   
   
   
}

function RemoveFile()
{
    var lst = document.getElementById("ListBox1");
    if(lst.selectedIndex == -1)
    {
        alert("请选择要删除的附件!");
        return;
    }
   
    var id = lst.value;
    div1.removeChild(document.all[id]);
    lst.removeChild(lst.options[lst.selectedIndex]);
    div1.firstChild.style.display = "";
   
}

//检查选项是否存在.
function CheckOptionsExists(value,ddl)
{
    for(var i=0;i <ddl.options.length;i++)
    {
        if(ddl.options[i].innerText == value)
        {
            return true;
        }
    }
    return false;
}

//-->
        </SCRIPT>

后台代码就比较简单了。没有过多的处理，只是一个简单的保存。

private void Button1_Click(object sender, System.EventArgs e)
        {
           
            for(int i=0;i <Request.Files.Count;i++)
            {
                if(Request.Files[i].ContentLength >0)
                {
                    string filename = System.IO.Path.GetFileName(Request.Files[i].FileName);
                    Request.Files[i].SaveAs(Server.MapPath(filename));
                    this.ListBox1.Items.Add(new ListItem(filename,filename));
                }

                this.lResult.Text = "保存成功!";
            }
           
        }