放一个按钮，按钮事件
C# codeprotected void Button1_Click(object sender, EventArgs e)
{
if (FileUpload1.HasFile == false)
{
Common.MessageAlert.Alert(Page, "您还没有选择图片！");
return;
}
else
{
//验证是否为图片格式
string filepath = FileUpload1.PostedFile.FileName;
string fileEx = filepath.Substring(filepath.LastIndexOf(".") + 1);
if (fileEx == "jpg" || fileEx == "bmp" || fileEx == "gif" || fileEx == "jpeg" || fileEx == "png"|| fileEx == "JPG"|| fileEx == "BMP" || fileEx == "GIF" || fileEx == "JPEG" || fileEx == "PNG")
{
//生成文件名yyyymmddhhmmssfff.fileex
string newfilename = System.DateTime.Now.ToString("yyyyMMddhhmmssfff");
string newfilename1 = newfilename + "." + fileEx;
//保存图片至~/img/
FileUpload1.PostedFile.SaveAs(Server.MapPath("~/img/" + newfilename1));
//image控件显示图片
Image1.ImageUrl = "~/img/" + newfilename1;
Image1.Visible = true;
}
else
{
Common.MessageAlert.Alert(Page, "你上传文件格式不正确！！！");
return;
}
}
}