Question

I need to combine 2 fields into 1 field. Name and Price.
However, I am getting a LINQ error

LINQ to Entities does not recognize the method ‘System.String ToString

Here is my linq statement.

        var results = ctx.Plans.Select(p => new PlansView
        {
            PlanID = p.planID,
            PlanActive = p.planActive,
            PlanCost = p.planCost,
            PlanName = p.planName,
            PlanNameAndCost = p.planName + " " + Convert.ToString(p.planCost)
        }).OrderBy(p => p.planName).ToList();

PlanNameAndCost = p.planName + ” ” + Convert.ToString(p.planCost) is causing the error.
I understand that SQL does not have a ToString,
but how can I get this to work?

Answer 1

PlanNameAndCost = p.planName + " " + Convert.ToString(p.planCost) is causing the error.

This is expected: the projection is executed on the RDBMS side; your SQL database has no idea what’s ToString. This member should be added when you are in memory, i.e. after AsEnumerable():

var results = ctx.Plans.Select(p => new PlansView
    {
        PlanID = p.planID,
        PlanActive = p.planActive,
        PlanCost = p.planCost,
        PlanName = p.planName
    }).OrderBy(p => p.planName)
    .AsEnumerable().Select(p => new PlansView
    {
        PlanID = p.planID,
        PlanActive = p.planActive,
        PlanCost = p.planCost,
        PlanName = p.planName,
        PlanNameAndCost = p.planName + " " + Convert.ToString(p.planCost)
    ).ToList();