Retrieving SPList Data From SharePoint Online Site using CSOM

using Microsoft.SharePoint.Client;

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Security;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace SPOnlineDataAccess

{

    public partial class Form1 : System.Windows.Forms.Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void LoadDefaultValues()

        {

            txtSiteUrl.Text = "https://abc.sharepoint.com/sites/testsite";

            txtListName.Text = "OnlineList";

            txtUserEmail.Text = "user1@xyz.com";

            txtPassword.Text = "pass@123qaz";

        }

        private void btnLoad_Click(object sender, EventArgs e)

        {

            DataTable dtResults = ReadSPList();

            dataGridView1.DataSource = dtResults;

        }

        private DataTable ReadSPList()

        {

            using (ClientContext clientContext = GetContextObject())

            {

                try

                {

                    DataTable dtListData = new DataTable();

                    //Creating DataTable Columns

                    dtListData.Columns.Add("Title", typeof(String));

                    dtListData.Columns.Add("Designation", typeof(String));

                    dtListData.Columns.Add("EmpID", typeof(String));

                    //Getting Data From SharePoint

                    Web web = clientContext.Web;

                    clientContext.Load(web, website => website.ServerRelativeUrl);

                    clientContext.ExecuteQuery();                  

                    //Read SPList called "OnlineList"

                    List myList = web.Lists.GetByTitle(txtListName.Text);

                    // This creates a CamlQuery that has a RowLimit of 1000, and also specifies Scope="RecursiveAll"

                    // so that it grabs all list items, regardless of the folder they are in.

                    CamlQuery query = CamlQuery.CreateAllItemsQuery(1000);

                    ListItemCollection items = myList.GetItems(query);

                    // Retrieve all items in the ListItemCollection from List.GetItems(Query).

                    clientContext.Load(items);

                    clientContext.ExecuteQuery();

                    for (int count = 0; count < items.Count; count++)

                    {

                        DataRow dr = dtListData.NewRow();

                        dr["Title"] = items[count]["Title"].ToString();

                        dr["Designation"] = items[count]["Designation"].ToString();

                        dr["EmpID"] = items[count]["EmpID"].ToString();

                        dtListData.Rows.Add(dr);

                    }

                    return dtListData;

                }

                catch (Exception ex)

                {

                    MessageBox.Show(ex.Message);

                    return null;

                }

            }

        }

        private ClientContext GetContextObject()

        {

            string siteUrl = txtSiteUrl.Text;

            string userName = txtUserEmail.Text;

            string password = txtPassword.Text;

            SecureString _password = GetPasswordFromInput(password);

            ClientContext context = new ClientContext(siteUrl);

            context.Credentials = new SharePointOnlineCredentials(userName, _password);

            return context;

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            LoadDefaultValues();

        }

        private SecureString GetPasswordFromInput(string password)

        {

            //Get the user's password as a SecureString

            SecureString securePassword = new SecureString();

            char[] arrPassword = password.ToCharArray();

            foreach (char c in arrPassword)

            {

                securePassword.AppendChar(c);

            }

            return securePassword;

        }

    }

}