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i have method in Bll Layer (use Stored Procedure ' SPShow() ')

C#

public static IList<Student> Show()
        {
            using (UniversityDataContext DB = new UniversityDataContext())
            {
                return (from t in DB.SPShow() select t).ToList<Student>();
            }            
        }

i want is good write for return type (IList) or no ?
if no i should use IQueryable or IEnumerable.If so, how should I convert ?

Posted 27-Sep-13 2:55am

Nekoomanesh

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Fredrik Bornander · Accepted Answer · 2013-09-27T02:58:00

Solution 1

Unless the callers need to change the result set then I'd recommend returning a IEnumerable of Students instead.

C#

public static IEnumerable<Student> Show() {
    using (var DB = new UniversityDataContext()) {
       return DB.SPShow(); // Might want to ToList here to prevent deferred execution
    }
}

Hope this helps,
Fredrik

Posted 27-Sep-13 2:58am

Fredrik Bornander

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Nekoomanesh 27-Sep-13 9:17am

is good but when i want data show in Grid View have error :
Object reference not set to an instance of an object.

it's my code :
protected void btnShow_Click(object sender, EventArgs e)
{
GridView1.DataSource = StudentBLL.Show();
GridView1.DataBind();
}

What should I do؟

Fredrik Bornander 27-Sep-13 9:24am

Debug it and figure out what's null. Then make sure that isn't null.