Compiler Error Message: CS0246: The type or namespace name 'Slider' could not be found

Question

i have created image insert page form using ASP.NET and C# and getting error while running on my hosting server it shows below error , but it works fine on localhost.

Server Error in '/' Application.

Compilation Error

Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.

Compiler Error Message: CS0246: The type or namespace name 'Slider' could not be found (are you missing a using directive or an assembly reference?)

Source Error:

Line 12: public partial class AddImage : System.Web.UI.Page Line 13: { Line 14: Slider sliderinsrt = new Slider(); Line 15: protected void Page_Load(object sender, EventArgs e) Line 16: {

i am posting code of insert image here

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";
            }
        }
    }
}

Answer 1

For people that receive this error and is working with Xamarin Forms, is missing this:

using Xamarin.Forms;

Answer 2

For anyone else searching this:

using UnityEngine.UI;