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c#linqcompiler-errorsienumerable
Polynomial
Polynomial

Reputation: 28316

Could not find an implementation of the query pattern on IEnumerable<T>

I've got an IEnumerable<T> as a parameter of a method, where T is a struct type:

using System;
using System.Collections.Generic;
using System.Linq;
using ...

public static class Foo
{
    internal struct CellDiff
    {
        public int RefX;
        public int RefY;
        public object OldValue;
        public object NewValue;
    }

    private static void ItemChanged(IEnumerable<CellDiff> diffs, int cellX, int cellY)
    {
        var change = from CellDiff diff in diffs
                     where diff.RefX == cellX && diff.RefY == cellY
                     select diff;

        ...
    }
}

This results in the following error:

(parameter) IEnumerable<CellDiff> diffs

Error:
Could not find an implementation of the query pattern for source type 'CellDiff'. 'Where' not found.

I've also tried doing diffs.AsQueryable(), to no avail.

I usually have no problem doing LINQ queries on IEnumerable<T>. I'm a bit lost as to what's happening here.

Upvotes: 1

Views: 1288

Answers (2)

Rawling
Rawling

Reputation: 50114

Specifying the type in LINQ query syntax creates a call to the Cast extension method with that type argument.

Do you have your own Cast defined somewhere?

Upvotes: 3

Pranay Rana
Pranay Rana

Reputation: 176916

you need to change query like , updated one is like this

 var change = from diff in diffs //changed like removed "CellDiff" from this
                     where diff.RefX == cellX && diff.RefY == cellY
                     select diff;

thre is no need of CellDiff after from in you query

Upvotes: 1

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