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我试图弄清楚为什么在请求中需要 aSqliteDbContext 时不考虑为我的下面定义的转换：Contains

public static class FSharpOptionExtensions
{
    public static T DefaultFromOption<T>(this FSharpOption<T> option)
        where T : IEquatable<T> =>
        (FSharpOption<T>.get_IsNone(option)
            ? default
            : option.Value)!;

    public static FSharpOption<T> ToOption<T>(this T source)
        where T : IEquatable<T> =>
        source.Equals(default)
            ? FSharpOption<T>.None
            : FSharpOption<T>.Some(source);
}

public class SqliteDbContext : DbContext
{
    public DbSet<SqliteRecord>? Records { get; set; }

    public SqliteDbContext() // : base()
    {
    }

    public SqliteDbContext(DbContextOptions<SqliteDbContext> options) : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        var faker = new Faker();
        var recordCount = faker.Random.Int(500, 1000);
        var records = Enumerable
            .Range(1, recordCount)
            .Select(index => new SqliteRecord
            {
                Id = index,
                Integer = faker.Random.Long(),
                Real = faker.Random.Double(),
                NullableText = faker.Name.FullName().OrNull(faker, .2f),
                NonNullableText = faker.Commerce.Product(),
                FSharpOptionText = FSharpOption<string>.Some(faker.Vehicle.Manufacturer())
                    .OrDefault(faker, 0.5f, FSharpOption<string>.None)
            });

        modelBuilder
            .Entity<SqliteRecord>()
            .Property(x => x.FSharpOptionText)
            .IsRequired(false)
            .HasConversion(new ValueConverter<FSharpOption<string>?, string>(
                option => option!.DefaultFromOption(),
                value => value.ToOption()));

        modelBuilder
            .Entity<SqliteRecord>()
            .HasKey(x => x.Id);

        modelBuilder
            .Entity<SqliteRecord>()
            .ToTable("Records")
            .HasData(records);
    }
}

var records = await _dbContext.Records.Select(x => new
{
    Id = x.Id,
    Integer = x.Integer,
    Real = x.Real,
    NullableText = x.NullableText,
    NonNullableText = x.NonNullableText,
    FSharpOptionText = x.FSharpOptionText!.DefaultFromOption()
}).Where(s =>
    s.NullableText!.ToLower().Contains("d") ||
    s.NonNullableText!.ToLower().Contains("d") ||
    s.FSharpOptionText.ToLower().Contains("d")
).ToListAsync();

我收到此错误：

System.InvalidOperationException：LINQ 表达式 'DbSet()
.Where(s => s.NullableText.ToLower().Contains("d") || s.NonNullableText.ToLower().Contains("d") || s.FSharpOptionText
.DefaultFromOption().ToLower().Contains("d"))' 无法翻译。

以可翻译的形式重写查询，或通过插入对 AsEnumerable()、AsAsyncEnumerable()、ToList() 或 ToListAsync() 的调用显式切换到客户端评估。有关详细信息，请参阅https://go.microsoft.com/fwlink/?linkid=2101038 。

在 Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVi sitor.g__CheckTranslated|15_0（ShapedQueryExpression 已翻译，<>c__DisplayClass15_0& ）
在 Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVi sitor.VisitMethodCall(MethodCallExpression methodCallExpression)
在 System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor访问者)
在 System.Linq.Expressions.ExpressionVisitor.Visit(Expression node) 在 Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVi sitor.VisitMethodCall(MethodCallExpression methodCallExpression) 在 System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor 访问者) 在 System.Linq.Expressions .ExpressionVisitor.Visit(Expression node) at Microsoft.EntityFrameworkCore.Query.QueryCompilationContext.CreateQueryExe cutor[TResult](Expression query) at Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult](Expression query, Boolean async) at Microsoft。 Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayCla ss12_0 上的 EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCor e[TResult]（IDatabase 数据库，表达式查询，IModel 模型，布尔异步）1.<ExecuteAsync>b__0() at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQu eryCore[TFunc](Object cacheKey, Func1 个编译器）在 Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult]（对象 cacheKey，Func 1 compiler) at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.ExecuteAsync[TR esult](Expression query, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.ExecuteAs ync[TResult](Expression expression, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable1.GetAsyncEnumerator（CancellationToken cancelToken）在 System.Runtime.CompilerServices.ConfiguredCancelableAsyncEnumerable 1.GetA syncEnumerator() at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsy nc[TSource](IQueryable1 源，CancellationToken cancelToken）

这对我来说没有多大意义，因为应该应用转换：

值转换器允许在读取或写入数据库时​​转换属性值。这种转换可以是从一个值到另一个相同类型的值（例如，加密字符串）或从一种类型的值到另一种类型的值（例如，将枚举值与数据库中的字符串进行转换。）

除非在“查询”时“阅读”不适用，如果确实如此，想知道是否有任何解决方法？有什么机制可以扩展表达式的解析方式？

顺便说一句，下面的查询工作得很好：

var records = await _dbContext.Records.Select(x => new
{
    Id = x.Id,
    Integer = x.Integer,
    Real = x.Real,
    NullableText = x.NullableText,
    NonNullableText = x.NonNullableText,
    FSharpOptionText = x.FSharpOptionText!.DefaultFromOption()
}).Where(x => x.Id == 1).ToListAsync();

info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 5.0.0-preview.6.20312.4 initialized 'SqliteDbContext
' using provider 'Microsoft.EntityFrameworkCore.Sqlite' with options: None
info: Microsoft.EntityFrameworkCore.Database.Command[20101]
      Executed DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeou
t='30']
      SELECT "r"."Id", "r"."Integer", "r"."Real", "r"."NullableText", "r"."NonNu
llableText", "r"."FSharpOptionText"
      FROM "Records" AS "r"
      WHERE "r"."Id" = 1
4

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