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File dialogs

docs/src/content/docs/features/dialogs/file.mdx

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Original Source

import { Card, CardGrid } from "@astrojs/starlight/components"; import { Image } from "astro:assets"; import fileDialogMacOS from "../../../../assets/screenshots/file-dialog-macos.png";

File dialogs

Wails provides native file dialogs with platform-appropriate appearance for opening files, saving files, and selecting folders. Simple API with file type filtering, multiple selection support, and default locations.

<Image src={fileDialogMacOS} alt="A native macOS file picker opened by a Wails application" style="max-width: 900px; margin: 1.5rem auto; display: block; border-radius: 10px; box-shadow: 0 8px 24px rgba(0,0,0,0.2);" />

The Wails API delegates to the operating system's picker, so familiar navigation, filtering, and selection behaviour are retained.

Creating File Dialogs

File dialogs are accessed through the app.Dialog manager:

go
app.Dialog.OpenFile()
app.Dialog.SaveFile()

Open File dialog

Select files to open:

go
path, err := app.Dialog.OpenFile().
    SetTitle("Select Image").
    AddFilter("Images", "*.png;*.jpg;*.gif").
    AddFilter("All Files", "*.*").
    PromptForSingleSelection()

if err != nil || path == "" {
    return
}

openFile(path)

Use cases:

  • Open documents
  • Import files
  • Load images
  • Select configuration files

Single File Selection

go
path, err := app.Dialog.OpenFile().
    SetTitle("Open Document").
    AddFilter("Text Files", "*.txt").
    AddFilter("All Files", "*.*").
    PromptForSingleSelection()

if err != nil || path == "" {
    // User cancelled or error occurred
    return
}

// Use selected file
data, _ := os.ReadFile(path)

Multiple File Selection

go
paths, err := app.Dialog.OpenFile().
    SetTitle("Select Images").
    AddFilter("Images", "*.png;*.jpg;*.jpeg;*.gif").
    PromptForMultipleSelection()

if err != nil {
    return
}

// Process all selected files
for _, path := range paths {
    processFile(path)
}

With Default Directory

go
path, err := app.Dialog.OpenFile().
    SetTitle("Open File").
    SetDirectory("/Users/me/Documents").
    PromptForSingleSelection()

Save File dialog

Choose where to save:

go
path, err := app.Dialog.SaveFile().
    SetFilename("document.txt").
    AddFilter("Text Files", "*.txt").
    AddFilter("All Files", "*.*").
    PromptForSingleSelection()

if err != nil || path == "" {
    return
}

saveFile(path, data)

Use cases:

  • Save documents
  • Export data
  • Create new files
  • Save as...

With Default Filename

go
path, err := app.Dialog.SaveFile().
    SetFilename("export.csv").
    AddFilter("CSV Files", "*.csv").
    PromptForSingleSelection()

With Default Directory

go
path, err := app.Dialog.SaveFile().
    SetDirectory("/Users/me/Documents").
    SetFilename("untitled.txt").
    PromptForSingleSelection()

Overwrite Confirmation

go
path, err := app.Dialog.SaveFile().
    SetFilename("document.txt").
    PromptForSingleSelection()

if err != nil || path == "" {
    return
}

// Check if file exists
if _, err := os.Stat(path); err == nil {
    dialog := app.Dialog.Question().
        SetTitle("Confirm Overwrite").
        SetMessage("File already exists. Overwrite?")

    overwriteBtn := dialog.AddButton("Overwrite")
    overwriteBtn.OnClick(func() {
        saveFile(path, data)
    })

    cancelBtn := dialog.AddButton("Cancel")
    dialog.SetDefaultButton(cancelBtn)
    dialog.SetCancelButton(cancelBtn)
    dialog.Show()
    return
}

saveFile(path, data)

Select Folder dialog

Choose a directory using the open file dialog with directory selection enabled:

go
path, err := app.Dialog.OpenFile().
    SetTitle("Select Output Folder").
    CanChooseDirectories(true).
    CanChooseFiles(false).
    PromptForSingleSelection()

if err != nil || path == "" {
    return
}

exportToFolder(path)

Use cases:

  • Choose output directory
  • Select workspace
  • Pick backup location
  • Choose installation directory

With Default Directory

go
path, err := app.Dialog.OpenFile().
    SetTitle("Select Folder").
    SetDirectory("/Users/me/Documents").
    CanChooseDirectories(true).
    CanChooseFiles(false).
    PromptForSingleSelection()

File Filters

Use the AddFilter() method to add file type filters to dialogs. Each call adds a new filter option.

Basic Filters

go
path, _ := app.Dialog.OpenFile().
    AddFilter("Text Files", "*.txt").
    AddFilter("All Files", "*.*").
    PromptForSingleSelection()

Multiple Extensions

Use semicolons to specify multiple extensions in a single filter:

go
dialog := app.Dialog.OpenFile().
    AddFilter("Images", "*.png;*.jpg;*.jpeg;*.gif;*.bmp").
    AddFilter("Documents", "*.txt;*.doc;*.docx;*.pdf").
    AddFilter("All Files", "*.*")

Pattern Format

Use semicolons to separate multiple extensions in a single filter:

go
// Multiple extensions separated by semicolons
AddFilter("Images", "*.png;*.jpg;*.gif")

Complete Examples

Open Image File

go
func openImage(app *application.App) (image.Image, error) {
    path, err := app.Dialog.OpenFile().
        SetTitle("Select Image").
        AddFilter("Images", "*.png;*.jpg;*.jpeg;*.gif;*.bmp").
        PromptForSingleSelection()

    if err != nil {
        return nil, err
    }

    if path == "" {
        return nil, errors.New("no file selected")
    }

    // Open and decode image
    file, err := os.Open(path)
    if err != nil {
        app.Dialog.Error().
            SetTitle("Open Failed").
            SetMessage(err.Error()).
            Show()
        return nil, err
    }
    defer file.Close()

    img, _, err := image.Decode(file)
    if err != nil {
        app.Dialog.Error().
            SetTitle("Invalid Image").
            SetMessage("Could not decode image file.").
            Show()
        return nil, err
    }

    return img, nil
}

Save Document with Validation

go
func saveDocument(app *application.App, content string) {
    path, err := app.Dialog.SaveFile().
        SetFilename("document.txt").
        AddFilter("Text Files", "*.txt").
        AddFilter("Markdown Files", "*.md").
        AddFilter("All Files", "*.*").
        PromptForSingleSelection()

    if err != nil || path == "" {
        return
    }

    // Validate extension
    ext := filepath.Ext(path)
    if ext != ".txt" && ext != ".md" {
        dialog := app.Dialog.Question().
            SetTitle("Confirm Extension").
            SetMessage(fmt.Sprintf("Save as %s file?", ext))

        saveBtn := dialog.AddButton("Save")
        saveBtn.OnClick(func() {
            doSave(app, path, content)
        })

        cancelBtn := dialog.AddButton("Cancel")
        dialog.SetDefaultButton(cancelBtn)
        dialog.SetCancelButton(cancelBtn)
        dialog.Show()
        return
    }

    doSave(app, path, content)
}

func doSave(app *application.App, path, content string) {
    if err := os.WriteFile(path, []byte(content), 0644); err != nil {
        app.Dialog.Error().
            SetTitle("Save Failed").
            SetMessage(err.Error()).
            Show()
        return
    }

    app.Dialog.Info().
        SetTitle("Saved").
        SetMessage("Document saved successfully!").
        Show()
}

Batch File Processing

go
func processMultipleFiles(app *application.App) {
    paths, err := app.Dialog.OpenFile().
        SetTitle("Select Files to Process").
        AddFilter("Images", "*.png;*.jpg").
        PromptForMultipleSelection()

    if err != nil || len(paths) == 0 {
        return
    }

    // Confirm processing
    dialog := app.Dialog.Question().
        SetTitle("Confirm Processing").
        SetMessage(fmt.Sprintf("Process %d file(s)?", len(paths)))

    processBtn := dialog.AddButton("Process")
    processBtn.OnClick(func() {
        // Process files
        var errs []error
        for i, path := range paths {
            if err := processFile(path); err != nil {
                errs = append(errs, err)
            }

            // Update progress
            // app.Event.Emit("progress", map[string]interface{}{
            //     "current": i + 1,
            //     "total":   len(paths),
            // })
            _ = i // suppress unused variable warning in example
        }

        // Show results
        if len(errs) > 0 {
            app.Dialog.Warning().
                SetTitle("Processing Complete").
                SetMessage(fmt.Sprintf("Processed %d files with %d errors.",
                    len(paths), len(errs))).
                Show()
        } else {
            app.Dialog.Info().
                SetTitle("Success").
                SetMessage(fmt.Sprintf("Processed %d files successfully!", len(paths))).
                Show()
        }
    })

    cancelBtn := dialog.AddButton("Cancel")
    dialog.SetCancelButton(cancelBtn)
    dialog.Show()
}

Export with Folder Selection

go
func exportData(app *application.App, data []byte) {
    // Select output folder
    folder, err := app.Dialog.OpenFile().
        SetTitle("Select Export Folder").
        SetDirectory(getDefaultExportFolder()).
        CanChooseDirectories(true).
        CanChooseFiles(false).
        PromptForSingleSelection()

    if err != nil || folder == "" {
        return
    }

    // Generate filename
    filename := fmt.Sprintf("export_%s.csv",
        time.Now().Format("2006-01-02_15-04-05"))
    path := filepath.Join(folder, filename)

    // Save file
    if err := os.WriteFile(path, data, 0644); err != nil {
        app.Dialog.Error().
            SetTitle("Export Failed").
            SetMessage(err.Error()).
            Show()
        return
    }

    // Show success with option to open folder
    dialog := app.Dialog.Question().
        SetTitle("Export Complete").
        SetMessage(fmt.Sprintf("Exported to %s", filename))

    openBtn := dialog.AddButton("Open Folder")
    openBtn.OnClick(func() {
        openFolder(folder)
    })

    dialog.AddButton("OK")
    dialog.Show()
}

Import with Validation

go
func importConfiguration(app *application.App) {
    path, err := app.Dialog.OpenFile().
        SetTitle("Import Configuration").
        AddFilter("JSON Files", "*.json").
        AddFilter("YAML Files", "*.yaml;*.yml").
        PromptForSingleSelection()

    if err != nil || path == "" {
        return
    }

    // Read file
    data, err := os.ReadFile(path)
    if err != nil {
        app.Dialog.Error().
            SetTitle("Read Failed").
            SetMessage(err.Error()).
            Show()
        return
    }

    // Validate configuration
    config, err := parseConfig(data)
    if err != nil {
        app.Dialog.Error().
            SetTitle("Invalid Configuration").
            SetMessage("File is not a valid configuration.").
            Show()
        return
    }

    // Confirm import
    dialog := app.Dialog.Question().
        SetTitle("Confirm Import").
        SetMessage("Import this configuration?")

    importBtn := dialog.AddButton("Import")
    importBtn.OnClick(func() {
        // Apply configuration
        if err := applyConfig(config); err != nil {
            app.Dialog.Error().
                SetTitle("Import Failed").
                SetMessage(err.Error()).
                Show()
            return
        }

        app.Dialog.Info().
            SetTitle("Success").
            SetMessage("Configuration imported successfully!").
            Show()
    })

    cancelBtn := dialog.AddButton("Cancel")
    dialog.SetCancelButton(cancelBtn)
    dialog.Show()
}

Best Practices

✅ Do

  • Provide file filters - Help users find files
  • Set appropriate titles - Clear context
  • Use default directories - Start in logical location
  • Validate selections - Check file types
  • Handle cancellation - User might cancel
  • Show confirmation - For destructive actions
  • Provide feedback - Success/error messages

❌ Don't

  • Don't skip validation - Check file types
  • Don't ignore errors - Handle cancellation
  • Don't use generic filters - Be specific
  • Don't forget "All Files" - Always include as option
  • Don't hardcode paths - Use user's home directory
  • Don't assume file exists - Check before opening

Platform Differences

macOS

  • Native NSOpenPanel/NSSavePanel
  • Sheet-style when attached to window
  • Follows system theme
  • Supports Quick Look preview
  • Tags and favourites integration

Windows

  • Native File Open/Save dialogs
  • Follows system theme
  • Recent files integration
  • Network location support

Linux

  • GTK file chooser
  • Varies by desktop environment
  • Follows desktop theme
  • Recent files support

Next Steps

<CardGrid> <Card title="Message dialogs" icon="information"> Info, warning, and error dialogs. 
[Learn More →](/features/dialogs/message)
</Card> <Card title="Custom dialogs" icon="puzzle"> Create custom dialog windows. 
[Learn More →](/features/dialogs/custom)
</Card> <Card title="Bindings" icon="rocket"> Call Go functions from JavaScript. 
[Learn More →](/features/bindings/methods)
</Card> <Card title="Events" icon="star"> Use events for progress updates. 
[Learn More →](/features/events/system)
</Card> </CardGrid>

Questions? Ask in Discord or check the file dialog examples.