CODEWITHSUNDEEP
c#entity-frameworkasp.net-mvc-4
Limna
Limna

Reputation: 403

Cannot implicitly convert type 'int?' to 'int' - either on Controller or on View Page

While executing below code, I got this error in my Controller:

Cannot implicitly convert type 'int?' to 'int'. An explicit conversion exists (are you missing a cast?)

Error comes on t.TOT_QTY in my controller.

Controller:

dcms = (from t in db.ASN_ITEM
                    ...
                    where
                      (t.TOT_QTY - t.SCND_QTY) != 0  
                    select new ASNVarianceRep
                    {                           
                        TOT_QTY = t.TOT_QTY,
                        SCND_QTY = t.SCND_QTY,
                        VAR_QTY = (t.SCND_QTY - t.TOT_QTY)                            
                    }).Distinct();

Where t.TOT_QTY is of type int? in the database. But the variable TOT_QTY is just an int on Model class.

Model:

public class ASNVarianceRep : ASN_ITEM
{  
    public int TOT_QTY { get; set; }
    ...
 }

If I changed public int TOT_QTY { get; set; } to public Nullable<int> TOT_QTY { get; set; }, Then error in the controller will be solved. But same error will be there on view page at line itotqty = itotqty + item.TOT_QTY;

View:

 @if (Model != null)
    {
        var itotqty = 0;
        foreach (var item in Model)
        {
            itotqty = itotqty + item.TOT_QTY;                
        <tr>                
            <td>
                @Html.DisplayFor(modelItem => item.TOT_QTY)
            </td>
            ...
        </tr>
        }
        <tr>                
            <td style="text-align: center"><b>@itotqty.ToString() </b></td>                
        </tr>

So, what I want is either I need to make the type of t.TOT_QTY from int? To int in Controller or make var itotqty = 0; from int to int? on view page. How to do so?

Upvotes: 2

Views: 7416

Answers (5)

Vini
Vini

Reputation: 2134

You could also convert a nullable int to int by the following

int temp= t.TOT_QTY ?? default(int);

Upvotes: 0

Mir Gulam Sarwar
Mir Gulam Sarwar

Reputation: 2648

Leave your changes in the model and then in your view

 totqty = itotqty + Convert.ToInt32(item.TOT_QTY);

Upvotes: 3

th1rdey3
th1rdey3

Reputation: 4388

I would suggest you to keep your model property nullable

public Nullable<int> TOT_QTY { get; set; }

or

public int? TOT_QTY { get; set; }

and handle it in your view

itotqty = itotqty + (int)(item.TOT_QTY ?? 0);

Upvotes: 1

AustinWBryan
AustinWBryan

Reputation: 3327

int? and int are basically two different types that you can't implicitly cast to, so you need to do an explicit cast. Explicit casts look like this:

int  myInt  = 3;
byte myByte = (Byte)myInt;

Where the (Byte) casts the int to a byte. It does this by create a new variable, preforming a hidden operation, then returning that value, much like a function.

To do that with your example, it would look like this:

dcms = (from t in db.ASN_ITEM
   ...
   where
       (t.TOT_QTY - t.SCND_QTY) != 0  
       select new ASNVarianceRep
       {                           
           TOT_QTY = (int)t.TOT_QTY,
           SCND_QTY = t.SCND_QTY,
           VAR_QTY = (t.SCND_QTY - t.TOT_QTY)                            
       }).Distinct();

But keep in mind that when you cast from a Type? to Type there is always a chance of memory loss, in the event you convert a null value to an int. I'm not sure what what null value is cast to, maybe 0, but point is, you have lost that data.

Upvotes: 1

Steve
Steve

Reputation: 9593

You can explicitly cast to an int in your query when assigning to your model. Currently it is trying to do an implicit cast as failing.

dcms = (from t in db.ASN_ITEM
       ...
       where
           (t.TOT_QTY - t.SCND_QTY) != 0  
           select new ASNVarianceRep
           {                           
               TOT_QTY = (int)t.TOT_QTY,
               SCND_QTY = t.SCND_QTY,
               VAR_QTY = (t.SCND_QTY - t.TOT_QTY)                            
           }).Distinct();

See this MSDN page for more info on explicit casting: https://msdn.microsoft.com/en-us/library/ms173105.aspx

Upvotes: 2

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