Add this line context.Load(lib); into your code before context.ExecuteQuery();, compare the results.
With the Load(lib), it informs the client object model to load the information of SP.List object when the application calls the ExecuteQuery method.
Here is demo to connect to SharePoint Online and get list/library by title:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint.Client;
using System.Security;
namespace TestGetFiles
{
class Program
{
private class Configuration
{
public static string ServiceSiteUrl = "https://tenant.sharepoint.com/<site>";
public static string ServiceUserName = "admin@tenant.onmicrosoft.com";
public static string ServicePassword = "<password>";
}
static ClientContext GetonlineContext()
{
var securePassword = new SecureString();
foreach (char c in Configuration.ServicePassword)
{
securePassword.AppendChar(c);
}
var onlineCredentials = new SharePointOnlineCredentials(Configuration.ServiceUserName, securePassword);
var context = new ClientContext(Configuration.ServiceSiteUrl);
context.Credentials = onlineCredentials;
return context;
}
static void Main(string[] args)
{
var clientContext=GetonlineContext();
List list = clientContext.Web.Lists.GetByTitle("<library>");
var fileName = "test.docx";
CamlQuery camlQuery = new CamlQuery();
camlQuery.ViewXml =
@"<View>
<Query>
<Where><Eq><FieldRef Name='FileLeafRef' /><Value Type='File'>" + fileName + @"</Value></Eq></Where>
</Query>
<ViewFields><FieldRef Name='FileRef' /><FieldRef Name='FileLeafRef' /></ViewFields>
</View>";
ListItemCollection listItems = list.GetItems(camlQuery);
clientContext.Load(listItems);
clientContext.ExecuteQuery();
foreach (ListItem oListItem in listItems)
{
Console.WriteLine(oListItem["FileRef"].ToString());
//do something
}
}
}
}
