Filter data for last 24 hours using c#?

Here i am calculating the server re开发者_开发问答start count.

i need the server restart count for last 24 hours.

string logType = "System";
EventLog ev = new EventLog(logType, System.Environment.MachineName);    
int count=0;
for (int i = ev.Entries.Count - 1; i >= 0; i--)
{
EventLogEntry CurrentEntry = ev.Entries[i];
if (CurrentEntry.Source.ToUpper() == "USER32")
{
count = count + 1;
}
}
ev.Close();

and i have tried like

DateTime dt = DateTime.Now;
TimeSpan ts = dt.Subtract(CurrentEntry.TimeGenerated);
int hours = (ts.Days * 24) + ts.Hours;

Any suggestion?

var ev = new EventLog("system", System.Environment.MachineName);
var count = ev.Entries.Cast<EventLogEntry>()
    .Where (e => e.TimeGenerated >= DateTime.Now.AddDays(-1) 
        && e.Source.Equals("USER32", StringComparison.CurrentCultureIgnoreCase)).Count();

Edit:

Considering jCoder's comment about the enteries being sorted on TimeGenerated. Using this code will gain performance:

var ev = new EventLog("system", System.Environment.MachineName);
int count = 0;
var y = DateTime.Now.AddDays(-1);
for (int i = ev.Entries.Count - 1; i >= 0 ; i--)
{
    if(ev.Entries[i].TimeGenerated < y)
        break;
    if(ev.Entries[i].Source.Equals("USER32", StringComparison.CurrentCultureIgnoreCase))
        count++;
}

Use CurrentEntry.TimeGenerated to check when it has happened.

put one more condition at if (CurrentEntry.Source.ToUpper() == "USER32") to check if TimeGenerated is in last 24 hours

This code will give you the count of events, in tha last day, that have a source of USER32 in the System event log.

int count; //your result  

//When yesterday became today
DateTime yesterday = DateTime.Now.Subtract(new TimeSpan(24, 0, 0));  

using (EventLog appLog = new EventLog("System"))
{
    count = appLog.Entries.OfType<EventLogEntry>().Where(
        e => (e.Source.ToUpperInvariant == "USER32") && 
             (e.TimeGenerated > yesterday)).Count();
}

EDIT: Or Even better, taking good bits from Mangus's answer

DateTime yesterday = DateTime.Now.AddDays(-1);
int count = 0;

using (Eventlog appLog = new EventLog("System"))
{
    count = appLog.Entries.OfType<EventLogEntry>().Count(
        e.Source.Equals("USER32", StringComparison.CurrentCultureIgnoreCase) && 
        e.TimeGenerated > yesterday
    )

}

If "USER32" events do not have a direct correllation with system restart events, this will not give you a count of system restarts.