Design control arrays & shared events

A name identifies the group; Index identifies the member#

A control array contains same-type visual controls with one Name and distinct Index values. Set the group name to txtCell, not txtCell(0); put the number in the separate Index field. The Designer and project tree display the combined member identity. A plain BASIC array of TextBox references is different: it points to existing controls and does not create any controls.

Choose a control whose metadata declares the event you need. Label, Image and Panel now support Click; array membership adds Index to the existing event signature.

Create the grid before writing its behavior#

Select one eligible, non-array visual control on a Form. Choose Design → Create Control Array…, the matching Arrange command in the Design ribbon, or the control’s context-menu command. The selected control is the template and becomes the first member; it is not left behind as a separate control.

Members inherit template properties and advance its TabIndex. The operation must leave the Form with no more than 2048 controls and components. Invalid values leave the project unchanged. Existing bound event headers receive Index as their first parameter in the same Undo step; a direct call to an old handler or other now-invalid source can prevent creation. Resolve the reported code issue first.

Practice with the complete six-cell board lesson, including exact dimensions, all event code and runtime checks.

One event procedure, one incoming member number#

Private Sub txtCell_Change(ByVal Index As Integer)
    lblStatus.Caption = "Cell " & Index & ": " & txtCell(Index).Text
End Sub

Index comes before the event’s existing parameters. Use Integer or Long, passed by value; a bare Index parameter is accepted for a synchronous array handler. Async handlers require explicit ByVal Index As Integer and an event that already supports async. They are not a way to make arbitrary parameterized events asynchronous.

Private Sub txtCell_KeyPress(ByVal Index As Integer, ByVal Character As String, ByRef Handled As Boolean)
    If txtCell(Index).Locked Then Handled = True
End Sub

For ListView ItemClick and ItemDoubleClick, distinguish the leading control-array Index from the event’s own item position, conventionally named ItemIndex. Double-clicking a member opens its shared default handler. The component pages show the ordinary single-control signature; an array handler adds Index before it.

Read members, not assumed positions#

Prefer For Each when gaps are possible. A counted loop from LBound to UBound can ask for a deleted member. Hiding a member changes Visible, not membership or Count. Programmatic Text changes also raise Change; guard bulk updates with a Boolean flag as the lesson demonstrates.

Understand promotion, paste, rename and Undo#

Promotion and joining are checked before applying changes. If a message begins with MCB4603, read the explanation of the code that must change; do not repeatedly paste Yes into an already failing project. A successful Create, paste promotion or rename is one Undo step covering the related layout, headers and target updates.

Point services at a member#

ContextMenu and ValidationProvider Target values select a specific member, for example txtCell(4). The bare group name is not a valid Target. Promotion of a plain control updates a matching Target to its first member. Deleting a targeted control leaves the ContextMenu items but clears its Target; choose a surviving member before Check or Run.

Create and remove a runtime member#

From build 843, Load txtCell(6) creates a member from the saved design-time template with the lowest Index. It begins hidden; set position and state before Visible True. The owning Form must perform Load with an unused Index. Unload removes runtime-created members only. The Modern Workbench includes both buttons, guards, bindings and complete handlers.

Count and bounds reflect membership. For Each over a dynamically loaded group uses a snapshot at loop entry. Adding a member does not extend that iteration. A removed control is no longer usable.

Give the AI the intended array boundary#

Right-click a member and choose Add Array to Chat when the assistant must edit the group and its shared event procedures. Ordinary Add to Chat on one member does not grant write access to a handler shared by the others. Adding a new Index remains outside the existing array scope and requires permission.

The array chip follows the array name, not a permanent group ID. After renaming the array, add it to scope again and review the chips before sending. AI grid generation uses one addControlArray operation, but still obeys member limits and requires complete handler code. See scope and permissions.