asp.net实现图片上传

    protected void btnAdd_Click(object sender, EventArgs e)
    {
        if (txtName.Text == "")
        {
            Tools.Alert("填写图片名称！", this);
            return;
        }
        string savePath = @"../images/picnews/";//图片保存路径
        string fileName = Server.HtmlEncode(this.getimagepath());
        string extension = System.IO.Path.GetExtension(fileName);//取得扩展名
        string ImageName = "";
        if (fileName != "nopic.gif")
        {
            if ((extension == ".jpg") | (extension == ".gif"))
            {
                ImageName = DateTime.Now.ToString("yyyyMMddhhmmssfff") + extension;
                savePath += ImageName;
                savePath = Server.MapPath(savePath);
            }
            else
            {
                Response.Write("<script>alert('文件上传格式错误');history.back(1);</script>");
                Response.End();
            }
        }
        else
        {
            ImageName = fileName;
        }
        if (fileName != "nopic.gif")
        {
            picupload.SaveAs(savePath);//这里是asp:FileUpload控件
        }
        AProduct.AddProduct(txtName.Text, FreeTextBox1.Text, ImageName, Convert.ToInt32(ddlType.SelectedValue), FreeTextBox2.Text);
        Tools.Alert("添加成功！", this);
    }
    /// <summary>
    /// 当没有选择图片时，使用默认图片。为了保存在数据库中。
    /// </summary>
    /// <returns></returns>
    private string getimagepath()
    {
        try
        {
            return this.picupload.HasFile ? picupload.FileName : "nopic.gif";
        }
        catch
        {
            return "nopic.gif";
        }
    }