why it is not storing the data in database

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

public partial class _Default : System.Web.UI.Page
{
    
    
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            FillGridView();
        }
    }

    private void FillGridView()
    {
        try
        {
            string cnString = ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString;
            SqlConnection con = new SqlConnection(cnString);
            GlobalClass.adap = new SqlDataAdapter("select * from TechnisionStatus", con);
            SqlCommandBuilder bui = new SqlCommandBuilder(GlobalClass.adap);
            GlobalClass.dt = new DataTable();
            GlobalClass.adap.Fill(GlobalClass.dt);
            GridView1.DataSource = GlobalClass.dt;
            GridView1.DataBind();
        }
        catch
        {
            Response.Write("<script>alert('ConnectionString Error...')</script>");
        }
    }
        protected void editRecord(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        FillGridView();
    }
        protected void cancelRecord(object sender, GridViewCancelEditEventArgs e)
        {
            GridView1.EditIndex = -1;
            FillGridView();

        }
        protected void AddNewRecord(object sender, EventArgs e)
        {
            
            try
            {
                if (GlobalClass.dt.Rows.Count > 0)
                {
                    GridView1.EditIndex = -1;
                    GridView1.ShowFooter = true;
                    FillGridView();
                }
                else
                {
                    GridView1.ShowFooter = false;
                    DataRow dr = GlobalClass.dt.NewRow();
                    dr["Date"] = 0;
                    dr["TechnisionName"] = 0;
                    dr["Task"] = 0;
                    dr["Status"] = 0;
                    dr["Remark"] = 0;
                    GlobalClass.dt.Rows.Add(dr);
                    GridView1.DataSource = GlobalClass.dt;
                    GridView1.DataBind();
                    GridView1.Rows[0].Visible = true;
                }
            }
            catch
            {
                Response.Write("<script> alert('Row not added in DataTable...') </script>");
            }
        }
        protected void AddNewCancel(object sender, EventArgs e)
        {
            GridView1.ShowFooter = false;
            FillGridView();
        }
    protected void InsertNewRecord(object sender, EventArgs e)
    {
        try
        {
            string strName = GlobalClass.dt.Rows[0]["TechnisionName"].ToString();
            if (strName == "0")
            {
                GlobalClass.dt.Rows[0].Delete();
                GlobalClass.adap.Update(GlobalClass.dt);
            }
            TextBox txtDate = GridView1.FooterRow.FindControl("txtNewDate") as TextBox;
            TextBox txtName = GridView1.FooterRow.FindControl("txtNewName") as TextBox;
            TextBox txtTask = GridView1.FooterRow.FindControl("txtNewTask") as TextBox;
            TextBox txtStatus = GridView1.FooterRow.FindControl("txtNewStatus") as TextBox;
            TextBox txtRemark = GridView1.FooterRow.FindControl("txtNewRemark") as TextBox;
            DataRow dr = GlobalClass.dt.NewRow();
            dr["Date"] = txtDate.Text.Trim();
            dr["TechnisionName"] = txtName.Text.Trim();
            dr["Task"] = txtTask.Text.Trim();
            dr["Status"] = txtStatus.Text.Trim();
            dr["Remark"] = txtRemark.Text.Trim();
            GlobalClass.dt.Rows.Add(dr);
            GlobalClass.adap.Update(GlobalClass.dt);
            GridView1.ShowFooter = false;
            FillGridView();
            }
        catch
        {
             Response.Write("<script> alert('Record not added...') </script>");
        }
    }
     
    
}