CODEWITHSUNDEEP
c#linqentity-framework
M.Doos
M.Doos

Reputation: 101

How to call custom method in linq query

i write a custom method like below :

 DateTime GetGregorianDate(string date)
    {
       return  new DateTime(int.Parse(date.Substring(0, 4)), int.Parse(date.Substring(5,    2)), int.Parse(date.Substring(8, 2)), new System.Globalization.PersianCalendar());
    }

and i want call this method in linq query like below :

 dynamic GetPlayerListByTeamName(string teamCode, FutsalEntities myEntity)
    {
        var player = (from p in myEntity.Players
                     where p.TeamCode == teamCode && (GetGregorianDate(p.ContractDateTo) <= DateTime.Now) ? true : false
                     select new { p.MeliCode, p.BearthDate, p.ContractNumber, p.InsuranceNumber, p.ContractDate, p.Mobile });
        return player;

    }

This is where the code is called :

  private void cmbTeams_SelectedIndexChanged(object sender, EventArgs e)
    {
        using (FutsalEntities myEntity = new FutsalEntities())
        {
            if (cmbTeams.SelectedIndex != -1 && myEntity.Players.Count() != 0)
            {
               dgPlayerList.DataSource =  GetPlayerListByTeamName(cmbTeams.SelectedValue.ToString(), myEntity);

but when i run application get this error :

LINQ to Entities does not recognize the method 'System.DateTime GetGregorianDate(System.String)' method, and this method cannot be translated into a store expression.

Is there any way to call this method in linq query?

Upvotes: 4

Views: 2231

Answers (2)

Tormod
Tormod

Reputation: 4573

Convert DateTime.Now to Persian Date, store it in a variable and then use that variable in the query, so that the server side query will do a persian date comparison.

Upvotes: 0

Sergey Berezovskiy
Sergey Berezovskiy

Reputation: 236188

Linq to Entities can't translate your method into SQL and execute it on server side. The only way to call your custom method is to move query into memory - e.g. by calling AsEnumerable() or ToList()

var players = from p in myEntity.Players.AsEnumerable()                      
              where GetGregorianDate(p.ContractDateTo) <= DateTime.Now
              select new { 
                  p.Name,
                  p.BearthDate, 
                  p.ContractNumber, 
                  p.InsuranceNumber, 
                  p.ContractDate, 
                  p.Mobile 
              };

Keep in mind, that this will transfer all players data over the network to local computer.

Upvotes: 4

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