Use native pickers safely

Open file, save, folder, color, font and print-related dialogs.

1 Form / control designs1 complete BASIC filesGuided sample project

Download complete project Complete event code

A cancelled dialog is a normal outcome. Read the result before performing a file operation, and never turn an empty selection into a default path silently. A picker grants the user a choice; it does not mean the later read or write cannot fail.

Step 1Prepare a safe practice project#

Extract the archive into a new writable folder, separate from your own application. Open CommonDialog.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": "f6b21cf4-c273-4af0-a809-52f1fdce390b",
  "name": "CommonDialogSample",
  "kind": "DesktopApp",
  "ai": {
    "storeChatsInProject": false
  },
  "language": {
    "dialect": "McBasic1",
    "requireExplicit": true,
    "compare": "Binary",
    "defaultArrayBase": 0
  },
  "application": {
    "bundleIdentifier": "com.mcbasic.samples.commondialog",
    "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 property	Value
`Caption`	`"CommonDialog — McBasic"`
`Width`	`760`
`Height`	`430`
`MinWidth`	`680`
`MinHeight`	`380`

Type	Name	Parent
CommandButton	`cmdOpen`	Form
CommandButton	`cmdSave`	Form
CommandButton	`cmdFolder`	Form
CommandButton	`cmdColor`	Form
CommandButton	`cmdFont`	Form
CommandButton	`cmdPrinter`	Form
CommandButton	`cmdPageSetup`	Form
CommandButton	`cmdClose`	Form
Label	`lblStatus`	Form
CommonDialog	`dlgCommon`	Component tray

cmdOpen · exact Inspector values

Property	Value
`Left`	`28`
`Top`	`34`
`Width`	`150`
`Height`	`36`
`Caption`	`"Open file"`
`TabIndex`	`0`
Anchor edges	Left, Top

cmdSave · exact Inspector values

Property	Value
`Left`	`196`
`Top`	`34`
`Width`	`150`
`Height`	`36`
`Caption`	`"Save file"`
`TabIndex`	`1`
Anchor edges	Left, Top

cmdFolder · exact Inspector values

Property	Value
`Left`	`364`
`Top`	`34`
`Width`	`150`
`Height`	`36`
`Caption`	`"Choose folder"`
`TabIndex`	`2`
Anchor edges	Left, Top

cmdColor · exact Inspector values

Property	Value
`Left`	`532`
`Top`	`34`
`Width`	`150`
`Height`	`36`
`Caption`	`"Choose color"`
`TabIndex`	`3`
Anchor edges	Right, Top

cmdFont · exact Inspector values

Property	Value
`Left`	`28`
`Top`	`92`
`Width`	`150`
`Height`	`36`
`Caption`	`"Choose font"`
`TabIndex`	`4`
Anchor edges	Left, Top

cmdPrinter · exact Inspector values

Property	Value
`Left`	`196`
`Top`	`92`
`Width`	`150`
`Height`	`36`
`Caption`	`"Printer settings"`
`TabIndex`	`5`
Anchor edges	Left, Top

cmdPageSetup · exact Inspector values

Property	Value
`Left`	`364`
`Top`	`92`
`Width`	`150`
`Height`	`36`
`Caption`	`"Page setup"`
`TabIndex`	`6`
Anchor edges	Left, Top

cmdClose · exact Inspector values

Property	Value
`Left`	`532`
`Top`	`92`
`Width`	`150`
`Height`	`36`
`Caption`	`"Close"`
`TabIndex`	`7`
Anchor edges	Right, Top

lblStatus · exact Inspector values

Property	Value
`Left`	`28`
`Top`	`168`
`Width`	`654`
`Height`	`120`
`Caption`	`"Choose a CommonDialog action. Cancel is reported separately from an error."`
`ForeColor`	`"#263238"`
Anchor edges	Left, Top, Right, Bottom

dlgCommon · exact Inspector values

Property	Value
`Title`	`"McBasic CommonDialog"`
`Filter`	`"Text files\|.txt;.md"`
`FileName`	`"notes.txt"`
`Color`	`"#1565C0"`
`Font`	`"System\|13\|Regular\|Normal"`
`PrinterName`	`""`
`PaperName`	`""`
`PageOrientation`	`"Portrait"`
`PageWidth`	`612`
`PageHeight`	`792`

Step 3Connect the events explicitly#

frmMain

Object	Event	Procedure	Parameters
`cmdOpen`	`Click`	`cmdOpen_Click`	`Click()`
`cmdSave`	`Click`	`cmdSave_Click`	`Click()`
`cmdFolder`	`Click`	`cmdFolder_Click`	`Click()`
`cmdColor`	`Click`	`cmdColor_Click`	`Click()`
`cmdFont`	`Click`	`cmdFont_Click`	`Click()`
`cmdPrinter`	`Click`	`cmdPrinter_Click`	`Click()`
`cmdPageSetup`	`Click`	`cmdPageSetup_Click`	`Click()`
`cmdClose`	`Click`	`cmdClose_Click`	`Click()`

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 ShowResult(ByVal Value As String)

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

Forms/frmMain.bas · ShowResult

Private Sub ShowResult(ByVal Value As String)
    If dlgCommon.Cancelled Then
        lblStatus.Caption = dlgCommon.LastAction + " cancelled"
    Else
        lblStatus.Caption = dlgCommon.LastAction + ": " + Value
    End If
End Sub

Private Sub cmdOpen_Click()