How to convert a passing string paramatre to int on asp.net MVC 3

Question

i'm a Asp.net MVC Develpoer and i have problem with converting string to int because i
because i nedd it on search. When i tryed to write this code on the Contoller:

public ViewResult Search(string textboxmvc)
{
    var student = from i in db.StudentSet  select i;

    if (!String.IsNullOrEmpty(textboxmvc))
    {
        student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                                   || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==int.Parse(textboxmvc));

    }

     return View(student);

}

it shows this problem:

Server Error in '/' Application.
LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NotSupportedException: LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression.

Source Error:


Line 42:                     </tr>
Line 43: 
Line 44:                 <% foreach (var item in Model) { %>
Line 45:                     <tr>
Line 46:                    


Source File: d:\aimen\Projects\Schoo_Project\Schoo_Project\Views\Students\Search.aspx    Line: 44

AD.Net · Accepted Answer · 2014-04-11 20:14:11Z

3

You have to parse it beforehand.

public ViewResult Search(string textboxmvc)
{
    int parsedId;
    int.TryParse(textboxmvc, out parsedId);
    var student = from i in db.StudentSet  select i;

    if (!String.IsNullOrEmpty(textboxmvc))
    {
        student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                                   || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==parsedId);

    }

     return View(student);

}

answered Apr 11, 2014 at 20:14

AD.Net

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1 Comment

Habib Over a year ago

+1 for int.TryParse, since it appears same textboxmvc is used for getting name as well as ID

aw04 · Accepted Answer · 2014-04-11 20:14:19Z

1

Assign it to another variable first.

if (!String.IsNullOrEmpty(textboxmvc))
{
    var textboxmvcAsInt = int.Parse(textboxmvc);
    student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                               || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==textboxmvcAsInt);

}

answered Apr 11, 2014 at 20:14

aw04

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Comments

Hamlet Hakobyan · Accepted Answer · 2014-04-11 20:14:16Z

0

Try this:

public ViewResult Search(string textboxmvc)
{
    var student = from i in db.StudentSet  select i;

    if (!String.IsNullOrEmpty(textboxmvc))
    {
        int val = int.Parse(textboxmvc);
        student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                                   || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==val);

    }

     return View(student);

}

answered Apr 11, 2014 at 20:14

Hamlet Hakobyan

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Comments

Andy T · Accepted Answer · 2014-04-11 20:14:24Z

0

Put the conversion outside of the LINQ expression:

var numericValue = int.Parse(textboxmvc);

student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                           || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==numericValue);

    }

answered Apr 11, 2014 at 20:14

Andy T

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Comments

MarcinJuraszek · Accepted Answer · 2014-04-11 20:14:28Z

0

Pares textbox content to int outside LINQ to Entities query:

if (!String.IsNullOrEmpty(textboxmvc))
{
    var id = int.Parse(textboxmvc)
    student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                               || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())
                               || s.Id == id);

}

answered Apr 11, 2014 at 20:14

MarcinJuraszek

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Comments

Jonesopolis · Accepted Answer · 2014-04-11 20:14:42Z

0

LINQ doesn't know how to convert Int.Parse to SQL code. Do the cast and assign it to a variable before the query.

answered Apr 11, 2014 at 20:14

Jonesopolis

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Comments

T McKeown · Accepted Answer · 2014-04-11 20:14:48Z

0

 if (!String.IsNullOrEmpty(textboxmvc))
 {
    int i = int.Parse(textboxmvc);
    student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())     
                 ||    s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==i);

  }

answered Apr 11, 2014 at 20:14

T McKeown

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Comments

Ragnar · Accepted Answer · 2014-04-11 20:17:47Z

0

I think that you have to make the conversion before Where like this:

if (!String.IsNullOrEmpty(textboxmvc))
    {
        var number = int.Parse(textboxmvc);
        student = student.Where(s => s.FirstName.ToUpper().Contains(textboxmvc.ToUpper())
                                   || s.LastName.ToUpper().Contains(textboxmvc.ToUpper())||s.Id==number);

    }

answered Apr 11, 2014 at 20:17

Ragnar

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