Use custom property Getters in Linq queries about linq2db HOT 5 CLOSED

[Expression] or [ExpressionMethod] don't do the trick?

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With this code, the query works:

public static class CustomFieldsExtension
{
    [Sql.Expression("CustomField1", PreferServerSide = true)]
    public static string cf1_MyCustomerProperty(this WmsLoadCarrierDTO lc) => lc.CustomField1;

    public static void cf1_SetMyCustomerProperty(this WmsLoadCarrierDTO lc, string value) => lc.CustomField1 = value;

    [Sql.Expression("CustomDate1", PreferServerSide = true)]
    public static DateTime? cd1_MyCustomerDate(this InfeedAdviceDTO iv) => iv.CustomDate1;

    public static void cd1_SetMyCustomerDate(this InfeedAdviceDTO iv, DateTime? value) => iv.CustomDate1 = value;
}

but the update in the database does not:

            var table = s.GetTable<WmsLoadCarrierDTO>());
            var u = table.Set(x => x.cf1_MyCustomerProperty(), "test2");
            u.Update();

Should this work? Is it an error that the Expression is not used here?

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Oh you want to set them also. I did not expect that to work, as [Expression] is an arbitrary string (or arbitrary linq expression) but UPDATE can only set a field, which is a lot more restrictive.

Not sure what you can do if you don't want to declare those as properties on the data class.

Note that the first argument to .Set(p, v) is an Expression, so if you had an extension method that returns such extension it should work. Not the best but could be a workaround:

static Expression<Func<WmsLoadCarrierDto, string>> MyCustomerSetter => dto => dto.CustomField1;

db.GetTable<WmsLoadCarrierDto>()
  .Set(MyCustomerSetter(), () => "ACME")
  .Update();

from linq2db.

Better to use ExpressionMethod with Sql.Property

public static class CustomFieldsExtension
{
    [ExpressionMethod(nameof(cf1_MyCustomerPropertyImpl)))]
    public static string cf1_MyCustomerProperty(this WmsLoadCarrierDTO lc) => lc.CustomField1;

    static Expression<Func<WmsLoadCarrierDTO, string>> cf1_MyCustomerPropertyImpl()
        => dto => Sql.Property<string>(dto, nameof(WmsLoadCarrierDTO.CustomField1));

    // other are similar
}

from linq2db.

works like a charm.

thanks

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