ASP.NET上传图片的简单方法

private void Button1_Click(object sender, System.EventArgs e)

{

string filename = "";

if (File1.PostedFile.ContentLength != 0)

{ 

string fn = File1.PostedFile.FileName;

filename =getRandomFilename();

filename += fn.Substring(fn.LastIndexOf("."));

if((fn.Substring(fn.LastIndexOf(".")+1).ToLower()=="jpg")||(fn.Substring(fn.LastIndexOf(".")+1).ToLower()=="gif"))

{

File1.PostedFile.SaveAs(Server.MapPath("file") + "/" + filename);

}

else

{

Response.Write("<script language='javascript'>alert('"+fn.Substring(fn.LastIndexOf(".")+1).ToLower()+"请选择格式为“jpg”或“gif”的图片或格式为“swf”的flash')</script>");

return;

}

Response.Write("<script language='javascript'>alert('上传成功')</script>");

}

else

{

Response.Write("<script language='javascript'>alert('没有图片')</script>");

return;

}

}

static public string getRandomFilename()

{

System.Random rand = new System.Random();

DateTime now = DateTime.Now;

string str = "";

str += now.Year.ToString();

//str += now.Year.ToString().Substring(now.Year.ToString().LastIndexOf("0")+1).Trim();

str += now.Month.ToString();

str += now.Day.ToString();

str += now.Hour.ToString();

str += now.Minute.ToString();

str += now.Second.ToString();

str += rand.Next(0, 1000);

return str; 

}