编译器错误消息：CS0246：找不到类型或命名空间名称'Slider'

我使用ASP.NET和C＃创建了图像插入页面表单，并在我的托管服务器上运行时出现错误，它显示如下错误，但它在localhost上工作正常 .

'/'应用程序中的服务器错误 . 编译错误说明：在编译服务此请求所需的资源期间发生错误 . 请查看以下特定错误详细信息并相应地修改源代码 . 编译器错误消息：CS0246：找不到类型或命名空间名称'Slider'（您是否缺少using指令或程序集引用？）源错误：第12行：公共部分类AddImage：System.Web.UI.Page Line 13：{第14行：Slider sliderinsrt = new Slider（）;第15行：protected void Page_Load（object sender，EventArgs e）第16行：{

我在这里发布插入图像的代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Data;
using System.Data.SqlClient;
//using System.Controls;

public partial class AddImage : System.Web.UI.Page
{
    Slider sliderinsrt = new Slider();
    protected void Page_Load(object sender, EventArgs e)
    {
        Label5.Visible = false;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        sliderinsrt.Title = TextBox1.Text;
        sliderinsrt.Description = TextBox2.Text;
        sliderinsrt.ImageName = FileUpload1.PostedFile.FileName;
        SaveImage();    
        int mode=0;
     string conn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
     SqlConnection con = new SqlConnection(conn);

        con.Open();
        SqlCommand cmd = new SqlCommand("InsertImage", con);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@Id", sliderinsrt.ID);
        cmd.Parameters.AddWithValue("@Title", sliderinsrt.Title);
        cmd.Parameters.AddWithValue("@Description", sliderinsrt.Description);
        cmd.Parameters.AddWithValue("@ImageName", sliderinsrt.ImageName);
        cmd.Parameters.AddWithValue("@mode", mode);
        cmd.ExecuteNonQuery();
        Label5.Visible = true;
        Label5.Text = "Successfully Saved";
        con.Close();    
        TextBox1.Text="";
        TextBox2.Text="";                 
    }      

    private void SaveImage()
    {
        string message = string.Empty;
        if (FileUpload1.HasFile)
        {
            string ext = System.IO.Path.GetExtension(this.FileUpload1.PostedFile.FileName);
            ext = ext.ToLower();

            if (ext == ".gif" || ext == ".png" || ext == ".jpg" || ext == ".jpeg" || ext == ".bmp")
            {
                string fileName = System.IO.Path.GetFileName(FileUpload1.PostedFile.FileName);
                Session["fileName"] = fileName;
                FileUpload1.PostedFile.SaveAs(Server.MapPath("~/UploadSliderImage/" + fileName).Replace("\\", "//"));               
            }
            else
            {
                message = "Invalid File Format";
            }
        }
    }
}