图片上传支持预览（C#） Fred

用到的命名空间：

using System.Data.SqlClient;
using System.IO;
using System.Xml;

<script type="text/javascript" language="javascript">
<!--
function PreviewImg()
{
//原来的预览代码，不支持 IE7。
var oldPreview = document.getElementById("newPreview");
oldPreview.innerHTML = "<img src=\"" + document.getElementById("upload").value + "\" width=\"100%\" height=\"300px\" />";

//新的预览代码，支持 IE6、IE7、IE8。
var newPreview = document.getElementById("newPreview");
newPreview.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = document.getElementById("upload").value;

}
//-->
</script>



<input id="upload" runat="server" name="upload" type="file" style=" 250px;
font-size: 12px;" onchange="javascript:PreviewImg();" />

后台代码：

protected void btnupload_ServerClick(object sender, EventArgs e)
{
string strFileName = "";
XmlDocument document = new XmlDocument();
document.Load(Server.MapPath("UploadFile.xml"));
XmlNodeList cn = document.SelectNodes("fileset");
string pathfile = cn.Item(0).SelectSingleNode("upload").Attributes["path"].Value.ToString();
string strfileExt = cn.Item(0).SelectSingleNode("fileformat").InnerText.ToString();
if (strfileExt.IndexOf(System.IO.Path.GetExtension(upload.PostedFile.FileName)) == -1)
{
Page.ClientScript.RegisterStartupScript(Page.GetType(), "", "<script language='javascript'>alert('只支持.jpg文件上传。');</script>");
return;
}
if ( selbanner.Value == "-2")
{
Page.ClientScript.RegisterStartupScript(Page.GetType(),"","<script>alert(\"请您选择所属频道！\");</script>");
return;
}
using (scn = new SqlConnection())
{
scn.ConnectionString = connectionstring;
scn.Open();
using (scm = new SqlCommand())
{
scm = scn.CreateCommand();
scm.CommandType = CommandType.StoredProcedure;
scm.CommandText = "flash_upload_ADD";

scm.Parameters.Add("@picdiscription", SqlDbType.VarChar, 50);
scm.Parameters["@picdiscription"].Value = this.txtdiscription.Value;

scm.Parameters.Add("@piclink", SqlDbType.VarChar, 500);
scm.Parameters["@piclink"].Value = this.piclink.Value;

scm.Parameters.Add("@picname", SqlDbType.VarChar, 50);
strFileName = pathfile + "/" + System.DateTime.Now.Year.ToString() + System.DateTime.Now.Month.ToString() + System.DateTime.Now.Day.ToString() + System.DateTime.Now.Hour.ToString() + System.DateTime.Now.Minute.ToString() + System.DateTime.Now.Millisecond.ToString() + System.IO.Path.GetExtension(upload.PostedFile.FileName);
scm.Parameters["@picname"].Value = strFileName;

scm.Parameters.Add("@picorder", SqlDbType.Int);
scm.Parameters["@picorder"].Value = orderid.Value;

string bannerids = "";
foreach(ListItem li in selbanner.Items)
{
if ( li.Selected == true)
bannerids += li.Value + ",";
}
scm.Parameters.Add("@banner", SqlDbType.VarChar, 8000).Value = bannerids;

scm.Parameters.Add("@information", SqlDbType.VarChar, 50);
scm.Parameters["@information"].Direction = ParameterDirection.Output;

scm.ExecuteNonQuery();

Page.ClientScript.RegisterStartupScript(Page.GetType(),"","<script>alert('" + scm.Parameters["@information"].Value.ToString() + "');</script>");
}
}
DirectoryInfo directoryinfo = new DirectoryInfo(Server.MapPath(pathfile));
if (!directoryinfo.Exists)
{
directoryinfo.Create();
}
upload.PostedFile.SaveAs(Server.MapPath(strFileName));
this.txtdiscription.Value = "";
this.piclink.Value = "";
}

Tags - 图片上传支持预览 , c# , asp.net