manureini
commented
9 months ago Hello ;)
Thanks for you question! I'm really happy when someone is interested in this library and may using it.
I'm using the Query Builder in a wasm application, but it will also work on server side. In my case, there a people which can be filtered by a custom query. I've defined 3 different values, which can be combined with operators. I'm calling them Rule, but it's (in a simple use case) just the part of a rule without an operator.
RuleName="FirstName" defines the FirstName Rule with PropertyType="typeof(string)".
MQueryBuilderComplexField is an example for a dropdown of some values (in this case objects of class Event).
<MQueryBuilder T="object" @bind-RuleGroup="mModel.RuleGroup" @bind-RuleGroup:after="OnRulesChanged">
<MQueryBuilderField RuleName="FirstName" Title="@L[nameof(Loc.FirstName)]" PropertyType="typeof(string)" />
<MQueryBuilderField RuleName="LastName" Title="@L[nameof(Loc.LastName)]" PropertyType="typeof(string)" />
<MQueryBuilderComplexField T="Guid" RuleName="EventEmployed" Title="@L[Loc.RuleEventEmployed]" AllowedOperators="new MQueryBuilderConditionOperator[0]">
<FormTemplate>
<MSelect T="Event" Property="@nameof(Event.Name)" Options="mEvents" Value="mEvents.FirstOrDefault(e => e.Id == context.Value)" ValueChanged="async v => { await context.ValueChanged.InvokeAsync(v.Id); }" ValueExpression="@(RenderHelper.GetFakePropertyInfoExpression<Event>(string.Empty, "Id"))" />
</FormTemplate>
</MQueryBuilderComplexField>
</MQueryBuilder>In OnRulesChanged I serialize the MQueryBuilderRuleGroup mModel.RuleGroup property and send it to a controller.
If you are on ServerSide you can skip this step.
In the controller I do something like this:
var people = mEfContext.Set<Person>().Where(p => p.OwnerId != null);
var query = MQueryBuilderHelper.ApplyRules(people, pRuleGroup, (c) =>
{
return c switch
{
"FirstName" => (u, v) => u.FirstName.ToLower(),
"LastName" => (u, v) => u.LastName.ToLower(),
"EventEmployed" => (p, v) => efContext.Set<Employment>().Any(a => a.PersonId == p.Id && (object)a.EventId == v)
};
});
var result = query.ToArray();So we prepare a IQueryable (in this case my database table), the user configured MQueryBuilderRuleGroup and a callback, which will map RuleName to an part of a query. With this information the MQueryBuilderHelper will add the corresponding filter to the queryable.
There is a small trick implemented:
"FirstName" => (u, v) => u.FirstName.ToLower(),
Here the parameter v is not used. So MQueryBuilderHelper assumes, that there is an operator missing.
This is ok, because the user can select it and it will be applied by the helper.
"EventEmployed" => (p, v) => efContext.Set<Employment>().Any(a => a.PersonId == p.Id && (object)a.EventId == v)
In this case the parameter v is used. So no operator can be used in this case.
Thats why they are disabled in the ui AllowedOperators="new MQueryBuilderConditionOperator[0]"
For example in this case people needs an employment of a selected event to be in the result.
Fell free to ask any questions. I'd be happy to help you ;)
agriffard
What is exactly your purpose with the
MQueryBuilder?The sample does not go beyond declaring the fields you want to be able to filter on.
How do you declare an instance of the field in the page and then, how are you able in the code to retrieve the actual selected filters with their field, operator and value?
Thank you for your answer.