Card Refresh

A dashboard card can re-read its own data after the window is open, so a dashboard stays useful for monitoring instead of showing a snapshot from launch time.

How Refresh Works

Refresh is on demand, not on a timer. Give a card a -RefreshScript and it becomes refreshable:

1. Initial load: the card renders the -Value (or -Data) supplied when it was declared.
2. Trigger: the operator refreshes the card, or uses the dashboard's Refresh all, which fires every refreshable card on the visible page.
3. Execution: the RefreshScript runs in its own runspace, off the UI thread, so a slow query does not freeze the window.
4. UI update: whatever the script returns replaces the card's value or rows.

No interval parameter

There is no -RefreshInterval on a dashboard card, and nothing polls in the background. If you need a value that updates itself on a clock, use the Canvas module, where a control takes -Refresh <seconds> and the engine ticks it — see About Canvas.

Configuring Refresh

Simple Metric Refresh

Add-UIMetricCard -Step 'Main' -Name 'CPU' `
    -Title 'CPU Usage' `
    -Value 0 `
    -Unit '%' `
    -RefreshScript { (Get-CimInstance Win32_Processor | Measure-Object LoadPercentage -Average).Average }

DataGrid Refresh

Add-UITableCard -Step 'Main' -Name 'ProcGrid' `
    -Title 'Top Processes' `
    -Data @() `
    -RefreshScript { Get-Process | Sort-Object CPU -Descending | Select-Object -First 10 Name, Id, CPU }

Refresh Properties

Parameter	Description
-RefreshScript	A ScriptBlock returning the new value (MetricCard) or rows (TableCard / ChartCard). Supported on Add-UIMetricCard, Add-UIChartCard, Add-UITableCard and Add-UIStatusCard.

Performance Considerations

• Background execution: refresh scripts run in separate runspaces, so they do not block the UI.
• Cost per click: Refresh all fires every refreshable card at once, so keep the scripts cheap — a remote WMI query on a dozen cards is a dozen remote queries.
• Error handling: a script that throws leaves the card showing its last known value.

TIP

Use Get-CimInstance rather than Get-WmiObject in refresh scripts: it is faster and still supported.

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