C#

protected void Page_Load(object sender, EventArgs e)
       {

           using (ClientContext clientContext = new ClientContext("https://------------.sharepoint.com/sites/Solutions/"))
           {
              SecureString passWord = new SecureString();

               foreach (char c in "----------".ToCharArray()) passWord.AppendChar(c);

               clientContext.Credentials = new SharePointOnlineCredentials("---------@---------.onmicrosoft.com", passWord);

               List list = clientContext.Web.Lists.GetByTitle("Cases");

               CamlQuery query = new CamlQuery();
               query.ViewXml = "<View/>";
               Microsoft.SharePoint.Client.ListItemCollection items = list.GetItems(query);
               clientContext.Load(list);
               clientContext.Load(items);

               clientContext.ExecuteQuery();

               DataTable dt = new DataTable();

               dt.Columns.Add("Title");
               dt.Columns.Add("Email_Address");
               dt.Columns.Add("occupation");
               dt.Columns.Add("PlaceOfCity");
               dt.Columns.Add("Mobile_Number");


               foreach (Microsoft.SharePoint.Client.ListItem item in items)
               {

                   dt.Rows.Add(item["Title"].ToString(), item["Email_Address"].ToString(), item["occupation"].ToString(), item["PlaceOfCity"].ToString(), item["Mobile_Number"].ToString());

               }

               GridView1.DataSource = dt;
               GridView1.DataBind();
           }

       }