CODEWITHSUNDEEP
c#linqlambda
balajiboss
balajiboss

Reputation: 968

Adding conditions in dynamic linq

I want to write a dynamic linq query that checks for 'where' condition based on two time frames, startTime and errorTime. The present code is here,

IQueryable<LogFormat> errorLines = null;
if (!string.IsNullOrEmpty(errorStartTime) && !string.IsNullOrEmpty(errorTime))
{
    var sTime = DateTime.Parse(errorStartTime);
    var eTime = DateTime.Parse(errorTime);
    errorLines = from errorLine in File
                 where
                     (errorLine.DateTime >= sTime && errorLine.DateTime <= eTime) &&
                     (
                     errorLine.Level == "ERR"
                     || errorLine.Level == "WARN"
                     )
                 select errorLine;
}
else if (!string.IsNullOrEmpty(errorStartTime))
{
    var sTime = DateTime.Parse(errorStartTime);
    errorLines = from errorLine in File
                 where
                     errorLine.DateTime >= sTime
                     &&
                     (
                     errorLine.Level == "ERR"
                     || errorLine.Level == "WARN"

                     )
                 select errorLine;

}
else if (!string.IsNullOrEmpty(errorTime))
{
    var eTime = DateTime.Parse(errorTime);

    errorLines = from errorLine in File
                 where
                     errorLine.DateTime <= eTime
                     &&
                     (
                     errorLine.Level == "ERR"
                     || errorLine.Level == "WARN"
                   )
                 select errorLine;

}
else
{   
    errorLines = from errorLine in File
                 where
                     errorLine.Level == "ERR"
                     || errorLine.Level == "WARN"


                 select errorLine;

}

Can I know how to have just one query so that I can send start time and errortime dynamically to get the results?

Upvotes: 0

Views: 759

Answers (2)

cuongle
cuongle

Reputation: 75316

You can make it dynamic by calling the where clause multiple times, based on conditions:

var errorLines = File.Where(e => e.Level == "ERR" 
                              || e.Level == "WARN");                   

if (!string.IsNullOrEmpty(errorStartTime))
{
     var sTime = DateTime.Parse(errorStartTime);
     errorLines = errorLines.Where(e => e.DateTime >= sTime);
}

if (!string.IsNullOrEmpty(errorTime))
{
    var eTime = DateTime.Parse(errorTime);
    errorLines = errorLines.Where(e => e.DateTime <= eTime);
}

Upvotes: 2

bor1s
bor1s

Reputation: 39

You can dynamically build predicate and combine with And() Or() in using PredicateBuilder. Take a look at : http://www.albahari.com/nutshell/predicatebuilder.aspx

Upvotes: 0

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