C# Pass Lambda Expression as Method Parameter
Use a Func<T1, T2, TResult>
delegate as the parameter type and pass it in to your Query
:
public List<IJob> getJobs(Func<FullTimeJob, Student, FullTimeJob> lambda)
{
using (SqlConnection connection = new SqlConnection(getConnectionString())) {
connection.Open();
return connection.Query<FullTimeJob, Student, FullTimeJob>(sql,
lambda,
splitOn: "user_id",
param: parameters).ToList<IJob>();
}
}
You would call it:
getJobs((job, student) => {
job.Student = student;
job.StudentId = student.Id;
return job;
});
Or assign the lambda to a variable and pass it in.
If I understand you need following code. (passing expression lambda by parameter) The Method
public static void Method(Expression<Func<int, bool>> predicate) {
int[] number={1,2,3,4,5,6,7,8,9,10};
var newList = from x in number
.Where(predicate.Compile()) //here compile your clausuly
select x;
newList.ToList();//return a new list
}
Calling method
Method(v => v.Equals(1));
You can do the same in their class, see this is example.
public string Name {get;set;}
public static List<Class> GetList(Expression<Func<Class, bool>> predicate)
{
List<Class> c = new List<Class>();
c.Add(new Class("name1"));
c.Add(new Class("name2"));
var f = from g in c.
Where (predicate.Compile())
select g;
f.ToList();
return f;
}
Calling method
Class.GetList(c=>c.Name=="yourname");
I hope this is useful
Lambda expressions have a type of Action<parameters>
(in case they don't return a value) or Func<parameters,return>
(in case they have a return value). In your case you have two input parameters, and you need to return a value, so you should use:
Func<FullTimeJob, Student, FullTimeJob>