CODEWITHSUNDEEP
linqasp.net-mvc-4
Krasimir
Krasimir

Reputation: 259

Unable to show View if Database table don't have records

This method throws exception when db.Profits doesn't have any records. How to prevent explode page 

public double getProfitSum()
{
   return db.Profits.Where(p => p.IdUser.UserId == WebSecurity.CurrentUserId).Sum(p => p.Value);
}

Error :

The cast to value type 'Double' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.

Upvotes: 1

Views: 57

Answers (3)

Novice
Novice

Reputation: 2487

The reason must be Sum() expects not nullable value. But your result might give null.

try

return db.Profits.Where(p => p.IdUser.UserId == WebSecurity.CurrentUserId
   && p.Value != null).Select(x=>(double?)x.Value).Sum() ?? 0.0M;

Upvotes: 1

NoWar
NoWar

Reputation: 37632

or even better

    public double getProfitSum()
                {
        var result = db.Profits.Where(p => p.IdUser.UserId == WebSecurity.CurrentUserId
               && p.Value != null).Sum(p => p.Value);

 return result == null ? 0 : result;
        }

Upvotes: 0

Moondustt
Moondustt

Reputation: 884

try that:

    var result = db.Profits.Where(p => p.IdUser.UserId == WebSecurity.CurrentUserId).Sum(p => p.Value);

    if(result != null)
      {
          return result;
      }
    return 0;

Upvotes: 2

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