McBasic™Get McBasic™ ↗
Build 881
Hands-on tutorial · Input & events

Distinguish typing from searching

Use Change for feedback and Search for the search action.

1 Form / control designs1 complete BASIC filesGuided sample project

Typing a query and submitting it are separate interactions. Keep Change inexpensive and put the explicit lookup behind Search. A remote search should add a busy state and cancellation; this lesson establishes the event boundary first.

Step 1Prepare a safe practice project#

Extract the archive into a new writable folder, separate from your own application. Open SearchBox.mcbproj in McBasic™. Keep every declared source, layout, resource and migration file together.

To reconstruct it yourself, create a DesktopApp project and add the files declared below. In the complete project, follow these steps as a guided rebuild: replace each named source file once and Check after all its procedures are present.

Exact project configuration
project.mcproj
{
  "schemaVersion": 1,
  "projectId": "6f1dbbe2-73c3-4df4-a5ef-4aa73d3e8f4d",
  "name": "SearchBoxSample",
  "kind": "DesktopApp",
  "ai": {
    "storeChatsInProject": false
  },
  "language": {
    "dialect": "McBasic1",
    "requireExplicit": true,
    "compare": "Binary",
    "defaultArrayBase": 0
  },
  "application": {
    "bundleIdentifier": "com.mcbasic.samples.searchbox",
    "version": "0.1.0",
    "buildNumber": "1",
    "startupFormId": "form-main",
    "shutdownMode": "OnStartupFormClosed"
  },
  "forms": [
    {
      "id": "form-main",
      "typeName": "frmMain",
      "layout": "Forms/frmMain.form.json",
      "code": "Forms/frmMain.bas"
    }
  ],
  "modules": [],
  "classes": [],
  "tests": [],
  "references": [],
  "resources": [],
  "targets": [
    "osx-arm64"
  ],
  "capabilities": []
}

Step 2Build the Form and set its properties#

frmMain

Select the Form first and set its properties. Add containers before their children. These are initial Designer values, not statements to paste into a procedure.

Form propertyValue
Caption"SearchBox — McBasic"
Width560
Height260
MinWidth440
MinHeight220
TypeNameParent
SearchBoxsrchCustomersForm
LabellblStatusForm
srchCustomers · exact Inspector values
PropertyValue
Left48
Top54
Width360
Height34
Text""
Placeholder"Find a customer"
ReadOnlyFalse
TabIndex0
VisibleTrue
EnabledTrue
Anchor edgesLeft, Top
lblStatus · exact Inspector values
PropertyValue
Left48
Top112
Width440
Height32
Caption"Type a query or press Enter."
TabIndex1
VisibleTrue
EnabledTrue
Anchor edgesLeft, Top

Step 3Connect the events explicitly#

frmMain

ObjectEventProcedureParameters
srchCustomersChangesrchCustomers_ChangeChange()
srchCustomersSearchsrchCustomers_SearchSearch()
FormLoadForm_Load()

Step 4Enter the complete behavior#

Open the named source file. Enter declarations first, then every procedure. Expand a procedure for its full body, or copy the complete file. Helpers are required: do not stop after entering the first Click handler.

Forms/frmMain.bas

Enter these declarations at file scope, before the procedures.

Forms/frmMain.bas · declarations
Option Explicit
Private Sub Form_Load()

Initialize state before enabling dependent actions. Keep the shared declarations and startup dependencies with this procedure.

Forms/frmMain.bas · Form_Load
Private Sub Form_Load()
    srchCustomers.Placeholder = "Find a customer"
    srchCustomers.Text = "Ada"
End Sub
Private Sub srchCustomers_Change()

Read the current value or selection and update its dependent interface. The binding above determines which object calls this handler.

Forms/frmMain.bas · srchCustomers_Change
Private Sub srchCustomers_Change()
    lblStatus.Caption = "Text changed: " & srchCustomers.Text
End Sub
Private Sub srchCustomers_Search()

Enter this helper in the named source file, outside every other procedure. Its callers are included in the same project.

Forms/frmMain.bas · srchCustomers_Search
Private Sub srchCustomers_Search()
    lblStatus.Caption = "Searching for: " & srchCustomers.Text
End Sub
Copy the complete Forms/frmMain.bas file

Replace the file once; do not append duplicate procedures.

Forms/frmMain.bas
Option Explicit

Private Sub Form_Load()
    srchCustomers.Placeholder = "Find a customer"
    srchCustomers.Text = "Ada"
End Sub

Private Sub srchCustomers_Change()
    lblStatus.Caption = "Text changed: " & srchCustomers.Text
End Sub

Private Sub srchCustomers_Search()
    lblStatus.Caption = "Searching for: " & srchCustomers.Text
End Sub

Step 5Keep resources and storage reproducible#

No external resource or migration files are declared. Any inline migration, seed data or local JSON is present in the code above. Runtime application data and private preferences are not included in the archive.

Step 6Check, run and test the result#

Save all files and run Check. Resolve diagnostics before Run. Developer CLI users can work from the extracted folder:

Developer CLI
mcbasic check SearchBox.mcbproj
mcbasic run SearchBox.mcbproj

Acceptance checklist

  • Type a query and inspect Change feedback.
  • Submit the query and inspect Search feedback.
  • Clear it and submit again to exercise empty input.

Step 7Make one change and repeat the tests#

Reject whitespace-only queries in Search before beginning any lookup.

Save a working Git checkpoint first. Change one behavior, Check again and repeat the acceptance checklist. Compare with the downloaded solution if a regression appears.

Source baseline 20f4bfed6b · Build manifest