Noui Command Preview

Constructor Selection

Most commands (no graphic interaction):

public MyCommand()
    : base(uiLayout: CommandUILayout.NoUI, modal: true, suspendable: false) { }

Graphic view commands (mouse events or selection):

public MyCommand()
    : base(uiLayout: CommandUILayout.NoUI,
           supportFlags: CommandSupportFlags.Graphic,
           suspendable: false)
{
    CanSuspendActiveCommand = true;
}

Modal commands cannot have CommandSupportFlags.Graphic — modal blocks graphic events.

Writing a NoUI Command

Step 1: Determine the Category

Use the decision flow above.

Step 2: Clarify Business Logic

If the user's input does not clearly describe what the command should do, ask clarifying questions before writing code. Examples:

• What objects does this command operate on? (selected objects, all objects in a workspace, specific type?)
• What should happen to those objects? (delete, modify a property, copy data, navigate the view?)
• Should the operation be undoable (transactional) or not?
• Does it need a progress bar for large sets?
• Should it work on the current selection or prompt the user to pick something graphically?
• Are there any validation rules or error conditions to handle?

Do not guess business logic. Get clarity first, then proceed.

Step 3: Choose Constructor

Two choices cover almost all cases:

• Modal + non-suspendable — Categories 1, 2, 3, 6, 7
• Graphic + CanSuspendActiveCommand — Categories 4, 5

Step 4: Implement Using the Category Pattern

Read noui-command-patterns.md for the full pattern code for each category. Here is the general structure all NoUI commands follow:

public class MyNoUICommand : BaseFrameworkCommand
{
    public MyNoUICommand()
        : base(uiLayout: CommandUILayout.NoUI, modal: true, suspendable: false) { }

    public override void OnStart(int commandID, object argument)
    {
        base.OnStart(commandID, argument);

        // For transactional commands:
        CommitUndoMarker = "My Operation";
        CommitSuccessMessage = "Success.";
        CommitFailureMessage = "Failed.";

        using (BOCollection selectedObjects = ClientServiceProvider.SelectSet.SelectedObjects)
        {
            if (selectedObjects.Count == 0)
            {
                AbortUnsavedChanges();
                return;
            }

            foreach (BusinessObject bo in selectedObjects)
            {
                // Modify objects
            }
        }

        CommitUnsavedChanges();
        // Framework auto-stops the command when OnStart returns
    }

    public override void OnStop()
    {
        // Unsubscribe from events, clean up resources
        base.OnStop();
    }
}

For non-transactional commands (Category 1), omit the commit markers and CommitUnsavedChanges().

Common Services

// Selected objects (always dispose with 'using')
using (BOCollection selected = ClientServiceProvider.SelectSet.SelectedObjects) { }

// Toast notifications
ClientServiceProvider.MessageService.ShowMessage("Message", UxtMessageType.Information);

// Clipboard
ClientServiceProvider.ClipboardService.SetText(text);
Clipboard.SetDataObject(text);  // System.Windows.Clipboard — used by CopyPartNumberCommand

// Graphic view
ClientServiceProvider.GraphicViewMgr.ActiveGraphicView;

// Preferences
ClientServiceProvider.Preferences.GetBooleanValue("PrefKey", defaultValue);
ClientServiceProvider.Preferences.SetValue("PrefKey", newValue);

// Site/Plant model
MiddleServiceProvider.SiteMgr.ActiveSite.ActivePlant;

Commit Patterns

// Standard commit
CommitUnsavedChanges();

// Suppress notification, show custom message
CommitUnsavedChanges(suppressNotification: true);
ClientServiceProvider.MessageService.ShowMessage("Custom msg", UxtMessageType.Information);

// Per-item commit in batch loop (empty undo marker for subsequent commits)
ClientCommandExtensions.CommitChangesWithEmptyUndoMarker(this);

// Abort (rollback) when nothing changed or on error
AbortUnsavedChanges();

Coding Guidelines

All generated code must follow csharp-coding-guidelines.md — covers file header, naming conventions, var usage, braces/formatting, expression style, modifiers, usings, and the single exit point rule.

Key Rules

1. Always dispose BOCollection with using statements
2. Always unsubscribe events in OnStop
3. Set CommitUndoMarker before calling CommitUnsavedChanges() — it is required
4. Do NOT call StopCommand() in most NoUI commands — the framework auto-stops modal commands when OnStart returns. Only call it in Category 5 (interactive selection) and Category 7 (non-modal dialog) where the command stays alive waiting for user input
5. Modal commands cannot have CommandSupportFlags.Graphic — graphic events won't fire on modal commands
6. Set CanSuspendActiveCommand = true for view manipulation and selection commands

Reference Files

• noui-command-patterns.md — Complete reference with all 7 category patterns, constructor variations, decision flowchart, ProgressListener API, StopCommand() guidance, and common patterns. Always load this.
• list-of-services.md — Load when the command uses framework services beyond what the pattern template shows (SelectSet, WaitCursor, MessageService, GraphicViewMgr, Preferences, etc.).