Create, edit and delete persistent records

Complete a CRUD workflow with selection, refresh and export.

1 Form / control designs1 complete BASIC filesGuided sample project

Download complete project Complete event code

Treat the database write and the refreshed screen as two steps. Read the selected record identity before updating or deleting; never use a visual row position as a primary key. Parameterized commands keep entered values separate from SQL structure. Requery after a successful write so the screen reflects committed data.

Step 1Prepare a safe practice project#

Extract the archive into a new writable folder, separate from your own application. Open CustomerManager.mcproj 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

CustomerManager.mcproj

{
  "schemaVersion": 1,
  "projectId": "3e098138-bd6b-4d47-b1b0-77fa484c0b82",
  "name": "CustomerManager",
  "kind": "DesktopApp",
  "language": {
    "dialect": "McBasic1",
    "requireExplicit": true,
    "compare": "Binary",
    "defaultArrayBase": 0
  },
  "application": {
    "bundleIdentifier": "com.mcbasic.samples.customermanager",
    "version": "0.1.0",
    "buildNumber": "1",
    "startupFormId": "form-main",
    "shutdownMode": "OnStartupFormClosed"
  },
  "forms": [
    {
      "id": "form-main",
      "typeName": "MainForm",
      "layout": "Forms/MainForm.form.json",
      "code": "Forms/MainForm.bas"
    }
  ],
  "modules": [],
  "classes": [],
  "tests": [],
  "references": [],
  "resources": [],
  "targets": [
    "osx-arm64"
  ],
  "capabilities": []
}

Step 2Build the Form and set its properties#

MainForm

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 property	Value
`Caption`	`"CustomerManager — McBasic"`
`Width`	`900`
`Height`	`620`
`MinWidth`	`760`
`MinHeight`	`520`

Type	Name	Parent
Label	`lblName`	Form
TextBox	`txtName`	Form
Label	`lblEmail`	Form
TextBox	`txtEmail`	Form
CommandButton	`cmdSave`	Form
CommandButton	`cmdDelete`	Form
CommandButton	`cmdRefresh`	Form
CommandButton	`cmdExport`	Form
Label	`lblStatus`	Form
CommandButton	`cmdSeed`	Form
CommandButton	`cmdClear`	Form
CommandButton	`cmdQuit`	Form
DataGrid	`grdCustomers`	Form

lblName · exact Inspector values

Property	Value
`Left`	`24`
`Top`	`24`
`Width`	`90`
`Height`	`30`
`Caption`	`"Name"`
`TabIndex`	`0`
Anchor edges	Left, Top

txtName · exact Inspector values

Property	Value
`Left`	`120`
`Top`	`20`
`Width`	`250`
`Height`	`36`
`Text`	`""`
`TabIndex`	`1`
Anchor edges	Left, Top

lblEmail · exact Inspector values

Property	Value
`Left`	`390`
`Top`	`24`
`Width`	`80`
`Height`	`30`
`Caption`	`"Email"`
`TabIndex`	`2`
Anchor edges	Left, Top

txtEmail · exact Inspector values

Property	Value
`Left`	`470`
`Top`	`20`
`Width`	`250`
`Height`	`36`
`Text`	`""`
`TabIndex`	`3`
Anchor edges	Left, Top

cmdSave · exact Inspector values

Property	Value
`Left`	`24`
`Top`	`72`
`Width`	`140`
`Height`	`36`
`Caption`	`"Save"`
`TabIndex`	`4`
Anchor edges	Left, Top

cmdDelete · exact Inspector values

Property	Value
`Left`	`176`
`Top`	`72`
`Width`	`140`
`Height`	`36`
`Caption`	`"Delete"`
`TabIndex`	`5`
Anchor edges	Left, Top

cmdRefresh · exact Inspector values

Property	Value
`Left`	`328`
`Top`	`72`
`Width`	`140`
`Height`	`36`
`Caption`	`"Refresh"`
`TabIndex`	`6`
Anchor edges	Left, Top

cmdExport · exact Inspector values

Property	Value
`Left`	`480`
`Top`	`72`
`Width`	`140`
`Height`	`36`
`Caption`	`"Export CSV"`
`TabIndex`	`7`
Anchor edges	Left, Top

lblStatus · exact Inspector values

Property	Value
`Left`	`490`
`Top`	`116`
`Width`	`380`
`Height`	`32`
`Caption`	`"Starting..."`
`TabIndex`	`11`
Anchor edges	Left, Top

cmdSeed · exact Inspector values

Property	Value
`Left`	`24`
`Top`	`112`
`Width`	`150`
`Height`	`36`
`Caption`	`"Load 10,000"`
`TabIndex`	`8`
Anchor edges	Left, Top

cmdClear · exact Inspector values

Property	Value
`Left`	`186`
`Top`	`112`
`Width`	`120`
`Height`	`36`
`Caption`	`"Clear"`
`TabIndex`	`9`
Anchor edges	Left, Top

cmdQuit · exact Inspector values

Property	Value
`Left`	`318`
`Top`	`112`
`Width`	`100`
`Height`	`36`
`Caption`	`"Quit"`
`TabIndex`	`10`
Anchor edges	Left, Top

grdCustomers · exact Inspector values

Property	Value
`Left`	`24`
`Top`	`164`
`Width`	`846`
`Height`	`398`
`TabIndex`	`12`
`IsReadOnly`	`True`
`CanUserSortColumns`	`True`
`CanUserResizeColumns`	`True`
`HeadersVisible`	`True`
Anchor edges	Left, Top

Step 3Connect the events explicitly#

MainForm

Object	Event	Procedure	Parameters
`cmdSave`	`Click`	`cmdSave_Click`	`Click()`
`cmdDelete`	`Click`	`cmdDelete_Click`	`Click()`
`cmdRefresh`	`Click`	`cmdRefresh_Click`	`Click()`
`cmdExport`	`Click`	`cmdExport_Click`	`Click()`
`cmdSeed`	`Click`	`cmdSeed_Click`	`Click()`
`cmdClear`	`Click`	`cmdClear_Click`	`Click()`
`cmdQuit`	`Click`	`cmdQuit_Click`	`Click()`
`grdCustomers`	`SelectionChanged`	`grdCustomers_SelectionChanged`	`SelectionChanged()`
Form	`Shown`	`Form_Shown`	`()`

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/MainForm.bas`

Enter these declarations at file scope, before the procedures.

Forms/MainForm.bas · declarations

Option Explicit

Private mDb As Database
Private mRows As BindingSource
Private mSelectedId As Long
Private mSelectedRow As Long
Private mDeleteArmed As Boolean
Private mBusy As Boolean

Private Async Sub Form_Shown()

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

Forms/MainForm.bas · Form_Shown

Private Async Sub Form_Shown()
    Dim migrations As MigrationSet
    Dim version As Long
    Dim ignored As Variant

    mBusy = True
    cmdSave.Enabled = False
    cmdDelete.Enabled = False
    cmdRefresh.Enabled = False
    cmdExport.Enabled = False
    lblStatus.Caption = "Opening SQLite database..."
    Try
        Set mDb = Await Sqlite.OpenAsync(AppPaths.DataFile("customers.db"))
        Set migrations = Sqlite.CreateMigrationSet()
        migrations.Add 1, "CREATE TABLE IF NOT EXISTS Customers (ID INTEGER PRIMARY KEY, Name TEXT NOT NULL, Email TEXT NULL, CreatedAt TEXT NOT NULL)"
        version = Await mDb.ApplyMigrationsAsync(migrations)
        ignored = Await RefreshCustomers()

        cmdSave.Enabled = True
        cmdDelete.Enabled = True
        cmdRefresh.Enabled = True
        cmdExport.Enabled = True
        mBusy = False
        lblStatus.Caption = CStr(mRows.RowCount) & " customer(s) ready"
    Catch failure As McException
        mBusy = False
        lblStatus.Caption = "Database error " & CStr(failure.Number) & ": " & failure.Message
    End Try
End Sub

Private Async Sub cmdExport_Click()