== Why is this an issue?

The https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.components.supplyparameterfromqueryattribute[SupplyParameterFromQuery] attribute can be used to specify that a component parameter, of a routable component, comes from the query string.

Component parameters supplied from the query string support the following types:

* bool, DateTime, decimal, double, float, Guid, int, long, string.
* Nullable variants of the preceding types.
* Arrays of the preceding types, whether they're nullable or not nullable.

Query parameters should have one of the supported types. Otherwise, an unhandled exception will be raised at runtime.

[source,text]
----
Unhandled exception rendering component: Querystring values cannot be parsed as type '<type>'.
System.NotSupportedException: Querystring values cannot be parsed as type '<type>'
...
----

== How to fix it

Change the parameter type to one of the following ones:

* bool, DateTime, decimal, double, float, Guid, int, long, string.
* Nullable variants of the preceding types.
* Arrays of the preceding types, whether they're nullable or not nullable.

=== Code examples

==== Noncompliant code example

[source,csharp,diff-id=1,diff-type=noncompliant]
----
@page "/print"
<p> Parameter value is: @Value </p>
@code {
    [Parameter]
    [SupplyParameterFromQuery()]
    public TimeSpan Value { get; set; }     // Noncompliant
}
----

==== Compliant solution

[source,csharp,diff-id=1,diff-type=compliant]
----
@page "/print"
<p> Parameter value is: @Value </p>
@code {
    [Parameter]
    [SupplyParameterFromQuery()]
    public long Value { get; set; }         // Compliant
}
----

== Resources

=== Documentation

* Microsoft Learn - https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.components.supplyparameterfromqueryattribute[SupplyParameterFromQueryAttribute]