Test and measurement

Resource Picker <smart-resource-picker>

ResourcePicker selects an instrument or a channel: it lists the resources the application has found, grouped by interface and named by alias, filters them as text is typed, and reads a typed resource string before it is accepted.

<smart-resource-picker> · 10 properties, 5 methods, 4 events · source/modules/smart.resourcepicker.js

Usage in Blazor

The Razor component is <ResourcePicker> in Smart.Blazor.Industrial: every property is a parameter in PascalCase, every event an EventCallback<Event> named On<Event> whose ev["Detail"] is the typed detail class, and the methods are called on the @ref. String choices are enums. In a Blazor Web App (.NET 8 and later) the page needs an interactive render mode, for example @rendermode InteractiveServer; a statically rendered component stays empty.

@using Smart.Blazor.Industrial
@* .NET 8 and later: an interactive render mode, on the page or for the whole app *@
@rendermode InteractiveServer

<ResourcePicker @ref="resourcePicker" Value="GPIB0::16::INSTR"
    OnRefreshRequest="OnRefreshRequest" />

@code {
    ResourcePicker resourcePicker;

    void OnRefreshRequest(Event ev)
    {
        // the event carries no detail
    }

    // void Open()
    void Call() => resourcePicker.Open();
}

Properties

Parameter	Type, default	Description
Resources resources	IEnumerable<object>	Sets or retrieves the resources found. Each is an object with name (the resource string), alias, description, kind (gpib, tcpip, usb, serial, pxi, daq or other; worked out from the name when absent), available and an optional id. A plain string is taken as a resource name; null and anything else that is not an object is skipped, with one console warning per list.
Value value	string	Sets or retrieves the resource string in force.
Kinds kinds	IEnumerable<object>	Sets or retrieves the kinds listed. Empty lists every kind.
AllowCustom allowCustom	bool false	Accepts a typed resource the list does not have, once it parses as a resource name.
AvailableOnly availableOnly	bool false	Lists only the resources that are available.
Refreshable refreshable	bool true	Shows the refresh button, which raises refreshRequest.
Busy busy	bool false	Shows discovery in progress: the refresh button waits and the empty list says so. The application sets it while it searches.
Label label	string	Sets or retrieves the label above the field, which also names the combobox.
Placeholder placeholder	string	Sets or retrieves the text shown when nothing is selected. Empty uses the localized default.
Readonly readonly	bool false	Shows the value without allowing a change.

Methods

Method	Description
void Open()	Opens the list.
void Close()	Closes the list and shows the value again.
void Select(string name)	Selects a resource by name and raises change. A name the list does not have is taken only when custom entries are allowed and it parses; otherwise the hint says so. name string The resource string or id.
Task<object> Parse(string name) static: customElements.get('smart-resource-picker').parse(…); the wrapper's method of this name calls the element and fails	Also available as a static method of the class. Reads a resource string into its parts by the VISA resource syntax (IVI VPP-4.3): { kind, interface, ... } with the fields of its kind - board, address (0 to 30) and secondary (0 to 30, or 96 to 126 as the bus code some tools write; reported as written) for GPIB; board, host, addressType (ipv4, ipv6 or hostname), device, port, socket and protocol (vxi-11, hislip or socket) for LAN, where the host is an IPv4 address of four octets 0 to 255, an RFC 1123 host name or an IPv6 address - in brackets as VISA writes it (TCPIP0::[fe80::1]::inst0::INSTR), or bare where that is unambiguous, and the port is 0 to 65535; vendor, product (0 to 0xFFFF), serial and interfaceNumber for USB; board and port for serial (ASRL3, ASRLCOM3, and device paths such as ASRL/dev/ttyUSB0, whose board is null); board, bus (0 to 255), device (0 to 31), function (0 to 7), chassis and slot for PXI, from any of its three forms - PXI[bus]::device[::function], PXI[interface]::[bus-]device[.function] and PXI[interface]::CHASSISn::SLOTn[::FUNCn] - where only the last names a slot and the others give slot null, since a PCI device number is not a slot; device, channelType, channel and channelEnd for DAQ. The trailing ::INSTR may be left out, as the syntax allows. Text that is not a resource, including one that breaks these ranges (GPIB0::31::INSTR, TCPIP0::999.1.1.1::INSTR, PXI0::2::11::INSTR), is { kind: "other", name, reason } with reason the rule it broke in English, or null; empty text is null. name string The resource string.
Task<bool> IsValid(string name) static: customElements.get('smart-resource-picker').isValid(…); the wrapper's method of this name calls the element and fails	Also available as a static method of the class. True for a name the picker recognises as a resource: one that parse() reads as a kind other than "other", within the VISA ranges. name string The resource string.

Events

Every event is an EventCallback<Event>; Event is a dictionary and ev["Detail"] converts to the detail class named under the event.

Event	Description and detail
OnChange change ResourcePickerChangeEventDetail	This event is triggered when a resource is selected from the list or typed and accepted. Value string The resource string. PreviousValue string The one before. Resource object The entry of the list, or null for a typed resource. Parsed object The parts of the name, as parse() reads them.
OnRefreshRequest refreshRequest no detail	This event is triggered when the refresh button is pressed. The application performs the discovery, sets busy while it runs and assigns the resources it found.
OnOpen open no detail	This event is triggered when the list opens.
OnClose close no detail	This event is triggered when the list closes.

CSS variables

The component declares 4 CSS variables; the CSS page shows how to set them.

--smart-resource-height --smart-resource-background --smart-resource-border --smart-resource-list-background