关于.net上传图片不能预览的问题

来源：互联网发布：软件数据储存在哪里编辑：程序博客网时间：2024/05/18 03:21

项目中的WebConfig页面必须要引用下面一段代码

</appSettings>

并且项目中要建立对应的文件夹来保存图片文件

下面是ashx文件

#region 上传图片
/// <summary>
/// 上传图片
/// </summary>
/// <param name="context"></param>
private void UploadImage(HttpContext context)
{
string strRoot = System.Configuration.ConfigurationManager.AppSettings["uploadify_root"];
StringBuilder sbMsg = new StringBuilder();
String fileTypes = "gif,jpg,jpeg,png";
int maxSize = 1024 * 1024 * 2;

HttpPostedFile imgFile = context.Request.Files["Filedata"];
if (imgFile == null)
{
sbMsg.Append("{\"code\":\"201\",\"tips\":\"请上传图片！\"}");
context.Response.Write(sbMsg.ToString());
context.Response.End();
}

String dirPath = context.Server.MapPath(strRoot);
if (!Directory.Exists(dirPath))
{
try
{
Directory.CreateDirectory(strRoot);
}
catch
{
sbMsg.Append("{\"code\":\"201\",\"tips\":\"保存目录创建失败，请检查文件夹权限！\"}");
context.Response.Write(sbMsg.ToString());
context.Response.End();
}
}

String fileName = imgFile.FileName;
String fileExt = Path.GetExtension(fileName).ToLower();
ArrayList fileTypeList = ArrayList.Adapter(fileTypes.Split(','));

if (imgFile.InputStream.Length > maxSize)
{
sbMsg.Append("{\"code\":\"201\",\"tips\":\"超出最大上传限制（2M）！\"}");
context.Response.Write(sbMsg.ToString());
context.Response.End();
}

if (String.IsNullOrEmpty(fileExt) || Array.IndexOf(fileTypes.Split(','), fileExt.Substring(1).ToLower()) == -1)
{
sbMsg.Append("{\"code\":\"201\",\"tips\":\"请上传指定格式的图片文件！\"}");
context.Response.Write(sbMsg.ToString());
context.Response.End();
}

try
{
String ymd = DateTime.Now.ToString("yyyyMMdd", DateTimeFormatInfo.InvariantInfo);
dirPath += ymd + "/";
if (!Directory.Exists(dirPath))
{
Directory.CreateDirectory(dirPath);
}
string newDate = DateTime.Now.ToString("yyyyMMddHHmmssffff", DateTimeFormatInfo.InvariantInfo);
string strfn = StringUtility.FilterSpecial(imgFile.FileName);
String newFileName = strfn.Remove(strfn.Length - fileExt.Length, fileExt.Length) + "_" + newDate + fileExt;

//检测文件是否重名
if (File.Exists(context.Server.MapPath(strRoot + ymd + "/" + newFileName)))
{
sbMsg.Append("{\"code\":\"201\",\"tips\":\"已存在重名文件！\"}");
context.Response.Write(sbMsg.ToString());
context.Response.End();
}
String filePath = dirPath + newFileName;

imgFile.SaveAs(filePath);

String fileUrl = strRoot + ymd + "/" + newFileName;
sbMsg.Append("{\"code\":\"200\",\"tips\":\"上传成功！\",\"url\":\"" + fileUrl.Replace("\\", "\\\\") + "\"}");
context.Response.Write(sbMsg);
}
catch
{
context.Response.Write("{\"code\":\"201\",\"tips\":\"上传失败，请刷新后重试！\"}");
}
}
#endregion

下面是ajax

//upload files
$("#uploadify").uploadify({
'uploader': 'ajax/fileUpload.ashx?action=upload_image',//指定一般处理程序执行上传后的文件处理
'fileSizeLimit': '2MB',
'multi': false,
'fileTypeDesc': '图片文件',
'fileTypeExts': '*.gif; *.jpg; *.png',
'onUploadSuccess': function (file, data, response) {
var msg = $.parseJSON(data);
if (msg.code == "200") {
$('#img_show').attr('src', msg.url);
$('#videocover').val(msg.url);
} else {
Public.showMessage(false, msg.tips);
}
}
});

注意ajax、获取的值一定要在下面的id中获取

<td rowspan="6">图片预览
<div style="margin: 5px;" id="file_upload">
<input type="hidden" id="videocover" name="videocover" value="<%=strPicture %>" />
<img id="img_show" src="<%=strPicture %>" style="width: 185px; height: 150px; border: solid 1px #eeeeee;" />
</div>
</td>

1 0