How to import Sharepoint list in c sharp

Please install nuget package :

Microsoft.SharePoint.Client
Microsoft.SharePoint.Client.Online.CSOM
Microsoft.Sharepoint.Client.Runtime
SharePoint.Client.Office.Tools

Please use caml for Recursive list:

CamlQuery camlQuery = new CamlQuery();
            camlQuery.ViewXml = "<View Scope='RecursiveAll'><Query><Where><Geq><FieldRef Name='ID'/>" +
                "<Value Type='Number'>10</Value></Geq></Where></Query><RowLimit>3000</RowLimit></View>";

protected DataTable ImportListFromSharepoint()
        {
            DataTable dtsharepoint = new DataTable();

            string username = "your user name";
            string password = "your password";
            string siteUrl = "your sharepoint url/_layouts/15/viewlsts.aspx";
            SP.ClientContext clientContext = new SP.ClientContext(siteUrl);
            SecureString securePassword = new SecureString();
            foreach (var item in password.ToCharArray())
            {
                securePassword.AppendChar(item);
            }

            clientContext.Credentials = new SP.SharePointOnlineCredentials(username, securePassword);

            SP.List oList = clientContext.Web.Lists.GetByTitle("list name");

            SP.CamlQuery camlQuery = new SP.CamlQuery();
            camlQuery.ViewXml = "<View><Query><Where><Geq><FieldRef Name='ID'/>" +
                "<Value Type='Number'>10</Value></Geq></Where></Query><RowLimit>15000</RowLimit></View>";
            SP.ListItemCollection collListItem = oList.GetItems(camlQuery);
            SP.FieldCollection oFields = oList.Fields;

            clientContext.Load(collListItem);
            clientContext.ExecuteQuery();



            dtsharepoint.Columns.AddRange(new DataColumn[]
                                    {
                                        new DataColumn("ID"),
                                        new DataColumn("your share point column"),
                                    });

            foreach (ListItem oListItem in collListItem)
            {
                ID = "";
                your sharepoint column= "";
                


                DataRow dataRow = dtsharepoint.NewRow();

                foreach (var fieldValue in oListItem.FieldValues)
                {
                    var da = oListItem.FieldValues[fieldValue.Key];

                    if (da is Microsoft.SharePoint.Client.FieldUserValue[])
                    {
                        foreach (var d in ((Microsoft.SharePoint.Client.FieldUserValue[])da))
                        {
                            if (dtsharepoint.Columns.Contains(fieldValue.Key) == false)
                            {
                                dtsharepoint.Columns.Add(fieldValue.Key);
                            }

                            dataRow[fieldValue.Key] = dataRow[fieldValue.Key] + "," + d.LookupValue;


                        }

                    }
                    else if (da is Microsoft.SharePoint.Client.FieldUserValue)
                    {
                        if (dtsharepoint.Columns.Contains(fieldValue.Key) == false)
                        {
                            dtsharepoint.Columns.Add(fieldValue.Key);
                        }
                        dataRow[fieldValue.Key] = ((Microsoft.SharePoint.Client.FieldLookupValue)da).LookupValue;

                    }
                }

                dataRow["ID"] = ID;
                dataRow["your sharepoint column"] = your sharepoint column;
            }

            dt = dtsharepoint;
            return dt;
        }