ManageUser.aspx.cs

using System;
using System.Collections.Generic;
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;


public partial class _Default : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["DatabaseConnectionString1"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        print();
    }
    public void print() 
    {
        SqlDataAdapter adpt = new SqlDataAdapter("SELECT [id], [fullname], [email], [password] FROM [Users]", con);
        DataTable dt = new DataTable();
        adpt.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();

    }
    public void GridView1_SelectedIndexChanged(Object sender, EventArgs e)
    {
       
    }
    protected void Button2_Click(object sender, EventArgs e)
    {
        if (IsPostBack)
        {
            Button btn = (Button)sender;
            SqlCommand cmd = new SqlCommand("DELETE FROM [Users] WHERE [id] = @id", con);
            cmd.Parameters.AddWithValue("@id", btn.CommandArgument);

            con.Open();
            int s = cmd.ExecuteNonQuery();
            con.Close();

            if (s == 1)
            {
                Literal1.Text = "User Delete Successfully";
                print();
            }
            else
            {
                Literal1.Text = "Error";
            }

        }
    }
    protected void Button3_Click(object sender, EventArgs e)
    {
        Button btn = (Button)sender;
        SqlDataAdapter adpt = new SqlDataAdapter("SELECT [id], [fullname], [email], [password] FROM [Users] WHERE [id] ="+btn.CommandArgument, con);
        DataTable dt = new DataTable();
        adpt.Fill(dt);

        TextBox1.Text = dt.Rows[0][1].ToString();
        TextBox2.Text = dt.Rows[0][2].ToString();
        TextBox3.Text = dt.Rows[0][3].ToString();
        ViewState["user_id"] = btn.CommandArgument;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        SqlCommand cmd = new SqlCommand("UPDATE [Users] SET [fullname] = @fullname, [email] = @email, [password] = @password WHERE [id] = @id", con);
        cmd.Parameters.AddWithValue("@fullname", TextBox1.Text.Trim());
        cmd.Parameters.AddWithValue("@email", TextBox2.Text.Trim());
        cmd.Parameters.AddWithValue("@password", TextBox3.Text.Trim());
        cmd.Parameters.AddWithValue("@id", ViewState["user_id"]);

        con.Open();
        int s = cmd.ExecuteNonQuery();
        con.Close();

        if (s == 1)
        {
            TextBox1.Text = string.Empty;
            TextBox2.Text = string.Empty;
            TextBox3.Text = string.Empty;
            Literal1.Text = "Update successfully ";
            print();
        }
        else
        {
            TextBox1.Text = string.Empty;
            TextBox2.Text = string.Empty;
            TextBox3.Text = string.Empty;
        }
    }
}