基于ajax实现上传图片代码示例解析

js源码：

/// <reference path="jquery-1.8.3.js" />
/// <reference path="ajaxForm/jquery.form.js" />

/*!
* jQuery upload
* 用于上传单个文件，上传成功后,返回文件路径。
* 本插件依赖jQuery，jquery.form 请在使用时引入依赖的文件
*
* Date: 2014/4/23
*/
/*
使用:
html:
<div style="width: 100%; float: left;">
<input type="hidden" id="hfThumbnail" value="/uploads/2014/04/23/635338686611432716.jpg" />
<div class="imgdiv"></div>
<span class="img_span">
<input type="file" name="file" />
</span>

<input type="button" value="上传" class="upload" />
</div>
<div style="width: 100%; float: left;">
<input type="hidden" id="hfThumbnail" value="/uploads/2014/04/23/635338686611432716.jpg" />
<div class="imgdiv"></div>
<span class="img_span">
<input type="file" name="file" />
</span>

<input type="button" value="上传" class="upload" />
</div>

js:

$(document).ready(function () {

//$(".upload").upload({
//  uploadData: { id: "12233" },
//  successFn: function (response, statusText, xhr, $this) {
//    alert(response.Data.RelativePath)
//  },
//  deleteData: { id: function () { return "asdfasdf" } }
//});

$(".upload").upload({
uploadData: { id: "12233" },
successFn: "success",      //可以是字符串
deleteData: { id: function () { return "asdfasdf" } }
});
});

//上传成功后执行该函数
function success(response, statusText, xhr, $this) {
//比如插入编辑器
alert(response.Data.RelativePath + $this.attr("value"))
}
*/

(function ($) {
$.extend($.fn, {
upload: function (settings) {

var options = $.extend({
fileType: "gif|jpg|jpeg|png|bmp",            //允许的文件格式
uploadUrl: "/ajax/handler.ashx?action=uploadfile",   //上传URL地址
deleteUrl: "/ajax/handler.ashx?action=deletefile",   //删除URL地址
width: "",                       //图片显示的宽度
height: 100,                      //图片显示的高度
imgSelector: ".imgdiv",                 //图片选择器
uploadData: {},                     //上传时需要附加的参数
deleteData: {},                     //删除时需要附加的参数
deleteFn: function ($parent, showMessage) {       //删除图片的方法(默认方法使用POST提交)
methods.deleteImage($parent, showMessage);
},
beforeSubmitFn: "beforeUpload",             //上传前执行的方法 原型 beforeSubmit(arr, $form, options);
successFn: "uploadSuccess",               //上传成功后执行的方法 uploadSuccess(response, statusText, xhr, $this)
errorFn: "uploadError"                 //上传失败后执行的方法
}, settings);

//上传准备函数
var methods = {
//验证文件格式
checkFile: function (filename) {
var pos = filename.lastIndexOf(".");
var str = filename.substring(pos, filename.length);
var str1 = str.toLowerCase();
if (typeof options.fileType !== 'string') { options.fileType = "gif|jpg|jpeg|png|bmp"; }
var re = new RegExp("\.(" + options.fileType + ")$");
return re.test(str1);
},
//创建表单
createForm: function () {
var $form = document.createElement("form");
$form.action = options.uploadUrl;
$form.method = "post";
$form.enctype = "multipart/form-data";
$form.style.display = "none";
//将表单加当document上，
document.body.appendChild($form); //创建表单后一定要加上这句否则得到的form不能上传。document后要加上body,否则火狐下不行。
return $($form);
},
//创建图片
createImage: function () {
//不能用 new Image() 来创建图片，否则ie下不能改变img 的宽高
var img = $(document.createElement("img"));
img.attr({ "title": "双击图片可删除图片！" });
if (options.width !== "") {
img.attr({ "width": options.width });
}
if (options.height !== "") {
img.attr({ "height": options.height });
}
return img;
},
showImage: function (filePath, $parent) {
var $img = methods.createImage();
$parent.find(options.imgSelector).find("img").remove();
//要先append再给img赋值，否则在ie下不能缩小宽度。
$img.appendTo($parent.find(options.imgSelector));
$img.attr("src", filePath);
this.bindDelete($parent);
},
bindDelete: function ($parent) {
$parent.find(options.imgSelector).find("img").bind("dblclick", function () {
options.deleteFn($parent, true);
});
},
deleteImage: function ($parent, showMessage) {
var $fileInput = $parent.find("input:hidden");
if ($fileInput.val() !== "") {

var data = $.extend(options.deleteData, { filePath: $fileInput.val(), t: Math.random() });

$.post(options.deleteUrl, data, function (response) {

if (showMessage) { alert(response.MessageContent) }

if (response.MessageType == 1) {
$fileInput.val("");
$parent.find(options.imgSelector).find("img").remove();
}
}, "JSON");
}
},
onload: function ($parent) {
var hiddenInput = $parent.find("input:hidden");
if (typeof hiddenInput !== "undefined" && hiddenInput.val() !== "") {
var img = methods.createImage();
if ($parent.find(options.imgSelector).find("img").length > 0) { $parent.find(options.imgSelector).find("img").remove(); }
//要先append再给img赋值，否则在ie下不能缩小宽度。
img.appendTo($parent.find(options.imgSelector));
img.attr("src", hiddenInput.val());
methods.bindDelete($parent);
}
}
};
//上传主函数
this.each(function () {
var $this = $(this);
methods.onload($this.parent());
$this.bind("click", function () {
var $fileInput = $(this).parent().find("input:file");
var fileBox = $fileInput.parent();

if ($fileInput.val() === "") {
alert("请选择要上传的图片！");
return false;
}
//验证图片
if (!methods.checkFile($fileInput.val())) {
alert("文件格式不正确，只能上传格式为：" + options.fileType + "的文件。");
return false;
}
//若隐藏域中有图片，先删除图片
if ($fileInput.val() !== "") {
options.deleteFn($this.parent(), false);
//methods.deleteImage($this.parent(), false);
}

//创建表单
var $form = methods.createForm();

//把上传控件附加到表单
$fileInput.appendTo($form);
fileBox.html("<img src=\"/admin/styles/images/loading.gif\" />  正在上传... ");
$this.attr("disabled", true);

//构建ajaxSubmit参数
var data = {};
data.data = options.uploadData;
data.type = "POST";
data.dataType = "JSON";
//上传前
data.beforeSubmit = function (arr, $form, options) {

var beforeSubmitFn;
try { beforeSubmitFn = eval(options.beforeSubmitFn) } catch (err) { };
if (beforeSubmitFn) {
var $result = beforeSubmitFn(arr, $form, options);
if (typeof ($result) == "boolean")
return $result;
}
};
//上传失败
data.error = function (response, statusText, xhr, $form) {
var errorFn;
try { errorFn = eval(options.errorFn) } catch (err) { };
if (errorFn) {
errorFn(response.responseText, statusText, xhr, $this);
}
};
//上传成功
data.success = function (response, statusText, xhr, $form) {
//response = eval("(" + response + ")");
if (response.MessageType == 1) {
methods.showImage(response.Data.RelativePath, $this.parent());
$this.parent().find("input:hidden").val(response.Data.RelativePath);

var successFn;
try { successFn = eval(options.successFn) } catch (err) { };
if (successFn) {
$.ajaxSetup({ cache: false });//这个不能少，否则ie下会提示下载
successFn(response, statusText, xhr, $this);
}

} else {
alert(response.MessageContent);
}
$this.attr("disabled", false);
fileBox.html("<input type=\"file\" name=\"file\" />");
$form.remove();
};

try {
//开始ajax提交表单
$form.ajaxSubmit(data);
} catch (e) {
alert(e.message);
}
});
});
}
});
})(jQuery)

html代码：

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script src="Scripts/jquery/jquery-1.8.3.js"></script>
<script src="Scripts/jquery/ajaxForm/jquery.form.js"></script>
<script src="Scripts/jquery/jquery.upload.js"></script>
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div style="width: 100%; float: left;">
<input type="hidden" id="hfThumbnail" value="/uploads/2014/04/23/635338686611432716.jpg" />
<div class="imgdiv"></div>
<span class="img_span">
<input type="file" name="file" />
</span>

<input type="button" value="上传" class="upload" />
</div>
<div style="width: 100%; float: left;">
<input type="hidden" id="hfThumbnail" value="/uploads/2014/04/23/635338686611432716.jpg" />
<div class="imgdiv"></div>
<span class="img_span">
<input type="file" name="file" />
</span>

<input type="button" value="上传" class="upload" />
</div>
</form>
<script type="text/javascript">
$(document).ready(function () {
//$(".upload").upload({
//  uploadData: { id: "12233" },
//  successFn: function (response, statusText, xhr, $this) {
//    alert(response.Data.RelativePath)
//  },
//  deleteData: { id: function () { return "asdfasdf" } }
//});
$(".upload").upload({
uploadData: { id: "12233" },
successFn: "success",
deleteData: { id: function () { return "asdfasdf" } }
});
});

//上传成功后执行该函数
function success(response, statusText, xhr, $this) {
//比如插入编辑器
alert(response.Data.RelativePath + $this.attr("value"))
}
</script>
</body>
</html>

服务器端使用一般处理程序：

public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "application/json";
var action = context.Request.QueryString.Get<string>("action").ToLower();
var response = new JsonResult(StatusMessageType.Error, "没有权限或无效请求。").ToJson();
switch (action)
{

case "uploadfile":
if (context.Request.Files.Count > 0)
response = UploadFile(context.Request);
break;
case "deletefile":
response = DeleteFile(context.Request.Form);
break;
default:
break;
}
context.Response.Write(response);
}
/// <summary>
///
/// </summary>
/// <param name="file"></param>
/// <returns></returns>
private string UploadFile(HttpRequest request)
{
if (request.Files.Count == 0)
return new JsonResult(StatusMessageType.Error, "没有可处理的数据。").ToJson();
var id = request.Form.Get<string>("id", "");

var file = request.Files[0];
if (file == null || file.ContentLength <= 0 || string.IsNullOrEmpty(file.FileName))
return new JsonResult(StatusMessageType.Error, "没有可处理的数据。").ToJson();

//IStoreFile storeFile = null;

string[] datePaths = new string[] { "~/uploads/" };
datePaths = datePaths.Union(DateTime.Now.ToString("yyyy-MM-dd").Split('-')).ToArray();
var relativePath = storeProvider.JoinDirectory(datePaths);

var dirPath = HttpContext.Current.Server.MapPath(relativePath);

if (!System.IO.Directory.Exists(dirPath))
System.IO.Directory.CreateDirectory(dirPath);

var fileName = GenerateFileName(Path.GetExtension(file.FileName));

var filePath = Path.Combine(dirPath, fileName);
file.SaveAs(filePath);
return new JsonResult(StatusMessageType.Success, "上传成功。", new
{
RelativePath = WebUtility.ResolveUrl(Path.Combine(relativePath, fileName)),
Size = file.ContentLength,
Id = id,
}).ToJson();
}

public string DeleteFile(NameValueCollection form)
{
var filePath = form.Get<string>("filePath", "").Trim();
if (string.IsNullOrEmpty(filePath))
return new JsonResult(StatusMessageType.Error, "无效提交。").ToJson();

try
{
if (System.IO.File.Exists(HttpContext.Current.Server.MapPath(filePath)))
{
System.IO.File.Delete(HttpContext.Current.Server.MapPath(filePath));
return new JsonResult(StatusMessageType.Success, "文件删除成功。").ToJson();
}
else
{
return new JsonResult(StatusMessageType.Success, "找不到该文件。").ToJson();
}
}
catch (Exception)
{
return new JsonResult(StatusMessageType.Hint, "发生错误。").ToJson();
}
}

/// <summary>
/// 生成随机文件名
/// </summary>
/// <returns></returns>
private string GenerateFileName(string extension)
{
return DateTime.Now.Ticks.ToString() + extension;
}

程序使用的是framework4.0，所以使用了一些扩展方法。

JsonTesult类代码：

[Serializable]
public class JsonResult
{
private StatusMessageType _messageType;
private string _messageContent;

/// <summary>
///
/// </summary>
/// <param name="messageType"></param>
/// <param name="messageContent"></param>
/// <param name="data"></param>
public JsonResult(StatusMessageType messageType, string messageContent, object data = null)
{
_messageType = messageType;
_messageContent = messageContent;
Data = data;
}

public StatusMessageType MessageType
{
get { return _messageType; }
set { _messageType = value; }
}

public string MessageContent
{
get { return _messageContent; }
set { _messageContent = value; }
}

public object Data { get; set; }

public string ToJson()
{
JavaScriptSerializer serializer = new JavaScriptSerializer();
var json = serializer.Serialize(this);

//string p = @"\\/Date(\d+)\\/";
//MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString);
//Regex reg = new Regex(p);
//json = reg.Replace(json, matchEvaluator);
return json;
}

private static string ConvertJsonDateToDateString(Match m)
{
string result = string.Empty;
DateTime dt = new DateTime(1970, 1, 1);
dt = dt.AddMilliseconds(long.Parse(m.Groups[1].Value));
dt = dt.ToLocalTime();
result = dt.ToString("d");
return result;
}
}

StatusMessageType枚举类：

/// <summary>
/// 提示消息类别
/// </summary>
public enum StatusMessageType
{
/// <summary>
/// 权限不足
/// </summary>
NoAccess = -2,
/// <summary>
/// 错误
/// </summary>
Error = -1,
/// <summary>
/// 成功
/// </summary>
Success = 1,

/// <summary>
/// 提示信息
/// </summary>
Hint = 0
}

以上就是本文的全部内容，希望对大家的学习有所帮助

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