CODEWITHSUNDEEP
c#asp.netlinqlinq-to-sql
formatc
formatc

Reputation: 4323

LINQ to SQL execute method on select

Im really new to LINQ so I'm trying to figure out how to execute method with lambda expressions.

   public void GetData()
    {

     using (MyClassesDataContext context = new MyClassesDataContext())
                {
                    var problems = (from p in context.Problems select p).Take(10);
                    problems.Select(t => DisplayData(t.Text));
                }

    }

     public void DisplayData(string Text)
            { 

            }

I'm getting this error:

The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

at this line:

 problems.Select(t => DisplayData(t.Text));

What am I doing wrong?

Upvotes: 1

Views: 2264

Answers (3)

pkpapani
pkpapani

Reputation: 163

I think that if you make the following change to your code, it will work fine:

problems.Select(t => { DisplayData(t.Text); return true; })

Upvotes: 0

Pankaj
Pankaj

Reputation: 10115

Parallel.ForEach. Here is a sample example...

Reference - Executes a foreach operation in which iterations may run in parallel.

Sample Class

class abc
{
    public int i;
}

Sample LINQ Code

List<abc> d = new List<abc>();
d.Add(new abc { i = 1 });
d.Add(new abc() { i = 2 });
d.Add(new abc() { i = 3 });
d.Add(new abc() { i = 4 });

var problems = (from p in d select p).Take(2);
int k = 0;
System.Threading.Tasks.Parallel.ForEach(problems, j =>
    {
        abcd(ref j.i);
        k += j.i;
    }
);

Sample Function

void abcd(ref int i)
{
    i++;
}

Upvotes: -1

Krizz
Krizz

Reputation: 11552

Select operator is used to create a projection - i.e. the lambda expression passed as an argument instructs how to create new object out of each object in the collection.

What you want to do is, instead, to perform an action on each item from the collection. Use foreach loop for that:

var problems = (from p in context.Problems select p).Take(10);

foreach (var t in problems)
{
     DisplayData(t.Text);
}

Upvotes: 4

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