KryptonThemeComboBox

Overview

The KryptonThemeComboBox class provides a Krypton-themed ComboBox control that allows users to select from available Krypton themes. It inherits from KryptonComboBox and implements IKryptonThemeSelectorBase to provide theme selection functionality with automatic synchronization with the global palette system.

Class Hierarchy

System.Object
└── System.MarshalByRefObject
    └── System.ComponentModel.Component
        └── System.Windows.Forms.Control
            └── System.Windows.Forms.ComboBox
                └── Krypton.Toolkit.KryptonComboBox
                    └── Krypton.Toolkit.KryptonThemeComboBox

Constructor and Initialization

public KryptonThemeComboBox()

The constructor initializes enhanced features:

• KryptonManager Integration: Creates local KryptonManager instance for theme management
• Theme Population: Automatically populates with available themes using CommonHelperThemeSelectors.GetThemesArray()
• Initial Selection: Sets initial selected index based on current global palette
• Event Handling: Sets up global palette change event handling
• Synchronization: Maintains synchronization between local and global palette changes

Key Properties

KryptonCustomPalette Property

[Obsolete("Deprecated and will be removed in V110. Set a global custom palette through 'ThemeManager.ApplyTheme(...)'.")]
public KryptonCustomPaletteBase? KryptonCustomPalette { get; set; }

• Purpose: Custom palette assignment (deprecated)
• Category: Visuals
• Status: Obsolete - will be removed in V110
• Alternative: Use ThemeManager.ApplyTheme(...) for global custom palettes
• Default Value: null

DefaultPalette Property

[DefaultValue(PaletteMode.Global)]
public PaletteMode DefaultPalette { get; set; }

• Purpose: Sets the default palette mode for the control
• Category: Visuals
• Default Value: PaletteMode.Global
• Effect: Updates selected index when changed
• Usage: Controls which palette is selected by default

Hidden Properties

The following properties are hidden from the designer but remain accessible:

[Browsable(false)]
public override string Text { get; set; }

[Browsable(false)]
public new string FormatString { get; set; }

[Browsable(false)]
public new ListBox.ObjectCollection Items { get; }

[Browsable(false)]
public new int SelectedIndex { get; set; }

Advanced Usage Patterns

Basic Theme Selection

public void SetupBasicThemeComboBox()
{
    var themeComboBox = new KryptonThemeComboBox
    {
        Dock = DockStyle.Fill,
        DropDownStyle = ComboBoxStyle.DropDownList
    };

    // Handle theme selection
    themeComboBox.SelectedIndexChanged += OnThemeSelectionChanged;

    Controls.Add(themeComboBox);
}

private void OnThemeSelectionChanged(object? sender, EventArgs e)
{
    if (sender is KryptonThemeComboBox comboBox)
    {
        // Theme selection is automatically handled by the control
        // The global palette will be updated automatically
        Console.WriteLine($"Selected theme: {comboBox.SelectedItem}");
    }
}

Settings Dialog Integration

public class SettingsDialog : Form
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonLabel themeLabel;

    public SettingsDialog()
    {
        InitializeComponent();
        SetupThemeSelection();
    }

    private void SetupThemeSelection()
    {
        // Theme label
        themeLabel = new KryptonLabel
        {
            Text = "Application Theme:",
            Dock = DockStyle.Fill,
            LabelStyle = LabelStyle.NormalControl
        };

        // Theme combo box
        themeComboBox = new KryptonThemeComboBox
        {
            Dock = DockStyle.Fill,
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        // Add to layout
        var themeLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 2,
            RowCount = 1,
            Dock = DockStyle.Fill
        };

        themeLayout.Controls.Add(themeLabel, 0, 0);
        themeLayout.Controls.Add(themeComboBox, 1, 0);

        Controls.Add(themeLayout);
    }
}

Advanced Theme Management

public class AdvancedThemeManager
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonButton applyButton;
    private KryptonButton resetButton;
    private PaletteMode originalTheme;

    public AdvancedThemeManager()
    {
        InitializeComponents();
        SetupEventHandling();
    }

    private void InitializeComponents()
    {
        themeComboBox = new KryptonThemeComboBox
        {
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        applyButton = new KryptonButton
        {
            Text = "Apply Theme",
            Enabled = false
        };

        resetButton = new KryptonButton
        {
            Text = "Reset to Default"
        };

        // Store original theme
        originalTheme = KryptonManager.CurrentGlobalPaletteMode;
    }

    private void SetupEventHandling()
    {
        themeComboBox.SelectedIndexChanged += OnThemeSelectionChanged;
        applyButton.Click += OnApplyButtonClick;
        resetButton.Click += OnResetButtonClick;
    }

    private void OnThemeSelectionChanged(object? sender, EventArgs e)
    {
        // Enable apply button when theme changes
        applyButton.Enabled = true;
    }

    private void OnApplyButtonClick(object? sender, EventArgs e)
    {
        // Theme is already applied automatically by KryptonThemeComboBox
        // This is just for user feedback
        MessageBox.Show("Theme applied successfully!", "Theme Changed", 
            MessageBoxButtons.OK, MessageBoxIcon.Information);
        
        applyButton.Enabled = false;
    }

    private void OnResetButtonClick(object? sender, EventArgs e)
    {
        // Reset to original theme
        KryptonManager.GlobalPaletteMode = originalTheme;
        applyButton.Enabled = false;
    }
}

Theme Preview System

public class ThemePreviewManager
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonPanel previewPanel;
    private Timer previewTimer;

    public ThemePreviewManager()
    {
        InitializeComponents();
        SetupPreviewSystem();
    }

    private void InitializeComponents()
    {
        themeComboBox = new KryptonThemeComboBox
        {
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        previewPanel = new KryptonPanel
        {
            Size = new Size(200, 100),
            PanelBackStyle = PaletteBackStyle.PanelClient
        };

        // Add sample controls to preview panel
        var sampleButton = new KryptonButton
        {
            Text = "Sample Button",
            Location = new Point(10, 10)
        };

        var sampleLabel = new KryptonLabel
        {
            Text = "Sample Label",
            Location = new Point(10, 40)
        };

        previewPanel.Controls.Add(sampleButton);
        previewPanel.Controls.Add(sampleLabel);
    }

    private void SetupPreviewSystem()
    {
        // Setup preview timer for delayed preview
        previewTimer = new Timer { Interval = 500 }; // 500ms delay
        previewTimer.Tick += OnPreviewTimerTick;

        themeComboBox.SelectedIndexChanged += OnThemeSelectionChanged;
    }

    private void OnThemeSelectionChanged(object? sender, EventArgs e)
    {
        // Start preview timer
        previewTimer.Stop();
        previewTimer.Start();
    }

    private void OnPreviewTimerTick(object? sender, EventArgs e)
    {
        previewTimer.Stop();
        
        // Update preview panel with selected theme
        UpdatePreviewPanel();
    }

    private void UpdatePreviewPanel()
    {
        // The preview panel will automatically update with the new theme
        // since it uses the global palette system
        previewPanel.Invalidate();
    }
}

Integration Patterns

Main Form Theme Selector

public partial class MainForm : Form
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonStatusStrip statusStrip;

    public MainForm()
    {
        InitializeComponent();
        SetupThemeSelector();
    }

    private void SetupThemeSelector()
    {
        // Create theme combo box
        themeComboBox = new KryptonThemeComboBox
        {
            DropDownStyle = ComboBoxStyle.DropDownList,
            Width = 150
        };

        // Add to status strip
        statusStrip = new KryptonStatusStrip();
        statusStrip.Items.Add(new ToolStripSeparator());
        statusStrip.Items.Add(new ToolStripLabel("Theme:"));
        statusStrip.Items.Add(new ToolStripControlHost(themeComboBox));

        Controls.Add(statusStrip);
    }
}

Configuration Panel Integration

public class ConfigurationPanel : UserControl
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonHeaderGroup appearanceGroup;

    public ConfigurationPanel()
    {
        InitializeComponent();
        SetupAppearanceSection();
    }

    private void SetupAppearanceSection()
    {
        // Appearance group
        appearanceGroup = new KryptonHeaderGroup
        {
            Dock = DockStyle.Fill,
            HeaderStylePrimary = HeaderStyle.Panel
        };
        appearanceGroup.HeaderPrimary.Content.ShortText = "Appearance";

        // Theme selection
        var themeLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 2,
            RowCount = 1,
            Dock = DockStyle.Fill
        };

        var themeLabel = new KryptonLabel
        {
            Text = "Theme:",
            Dock = DockStyle.Fill,
            LabelStyle = LabelStyle.NormalControl
        };

        themeComboBox = new KryptonThemeComboBox
        {
            Dock = DockStyle.Fill,
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        themeLayout.Controls.Add(themeLabel, 0, 0);
        themeLayout.Controls.Add(themeComboBox, 1, 0);

        appearanceGroup.Panel.Controls.Add(themeLayout);
        Controls.Add(appearanceGroup);
    }
}

Dynamic Theme Switching

public class DynamicThemeSwitcher : UserControl
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonButton applyButton;
    private KryptonButton previewButton;
    private Form previewForm;

    public DynamicThemeSwitcher()
    {
        InitializeComponent();
        SetupThemeSwitcher();
    }

    private void SetupThemeSwitcher()
    {
        themeComboBox = new KryptonThemeComboBox
        {
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        applyButton = new KryptonButton
        {
            Text = "Apply Theme"
        };

        previewButton = new KryptonButton
        {
            Text = "Preview Theme"
        };

        // Event handlers
        applyButton.Click += OnApplyButtonClick;
        previewButton.Click += OnPreviewButtonClick;

        // Layout
        var layout = new KryptonTableLayoutPanel
        {
            ColumnCount = 3,
            RowCount = 1,
            Dock = DockStyle.Fill
        };

        layout.Controls.Add(themeComboBox, 0, 0);
        layout.Controls.Add(previewButton, 1, 0);
        layout.Controls.Add(applyButton, 2, 0);

        Controls.Add(layout);
    }

    private void OnApplyButtonClick(object? sender, EventArgs e)
    {
        // Theme is automatically applied by KryptonThemeComboBox
        MessageBox.Show("Theme applied to all open windows!", "Theme Applied", 
            MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

    private void OnPreviewButtonClick(object? sender, EventArgs e)
    {
        ShowThemePreview();
    }

    private void ShowThemePreview()
    {
        if (previewForm == null || previewForm.IsDisposed)
        {
            previewForm = new Form
            {
                Text = "Theme Preview",
                Size = new Size(400, 300),
                StartPosition = FormStartPosition.CenterParent
            };

            // Add sample controls to preview form
            var samplePanel = new KryptonPanel
            {
                Dock = DockStyle.Fill,
                PanelBackStyle = PaletteBackStyle.PanelClient
            };

            var sampleButton = new KryptonButton
            {
                Text = "Sample Button",
                Location = new Point(50, 50)
            };

            var sampleLabel = new KryptonLabel
            {
                Text = "Sample Label",
                Location = new Point(50, 100)
            };

            samplePanel.Controls.Add(sampleButton);
            samplePanel.Controls.Add(sampleLabel);
            previewForm.Controls.Add(samplePanel);
        }

        previewForm.ShowDialog(this);
    }
}

Performance Considerations

• Theme Synchronization: Efficient synchronization with global palette changes
• Event Handling: Optimized event handling to prevent unnecessary updates
• Memory Management: Proper disposal of local KryptonManager instance
• Theme Loading: Efficient theme array loading and population

Common Issues and Solutions

Theme Not Updating

Issue: Selected theme not applying to the application
Solution: Ensure proper event handling and synchronization:

themeComboBox.SelectedIndexChanged += (sender, e) =>
{
    // Theme is automatically applied by the control
    // No additional code needed
};

Custom Palette Issues

Issue: Custom palette not working with deprecated property
Solution: Use the new ThemeManager approach:

// Old way (deprecated)
// themeComboBox.KryptonCustomPalette = customPalette;

// New way
ThemeManager.ApplyTheme(customPalette);

Selection Not Synchronized

Issue: ComboBox selection not synchronized with global palette
Solution: Ensure proper initialization and event handling:

// The control automatically synchronizes with global palette changes
// Make sure the control is properly initialized
var themeComboBox = new KryptonThemeComboBox();

Design-Time Integration

Visual Studio Designer

• Designer: Uses KryptonStubDesigner for design-time support
• Toolbox: Available with custom bitmap representation
• Property Window: Theme-specific properties available
• Theme Population: Automatically populated with available themes

Property Categories

• Visuals: Theme-related properties (KryptonCustomPalette, DefaultPalette)
• Behavior: Standard ComboBox behavior properties
• Layout: Standard layout properties

Migration and Compatibility

From Standard ComboBox

// Old way
ComboBox themeComboBox = new ComboBox();
// Manual theme population and handling

// New way
KryptonThemeComboBox themeComboBox = new KryptonThemeComboBox();
// Automatic theme population and synchronization

From Deprecated Custom Palette

// Old way (deprecated)
themeComboBox.KryptonCustomPalette = customPalette;

// New way
ThemeManager.ApplyTheme(customPalette);
// Then use the theme combo box normally

Real-World Integration Examples

Application Settings Form

public partial class ApplicationSettingsForm : Form
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonButton okButton;
    private KryptonButton cancelButton;

    public ApplicationSettingsForm()
    {
        InitializeComponent();
        SetupThemeSettings();
    }

    private void SetupThemeSettings()
    {
        // Theme selection section
        var themeGroup = new KryptonHeaderGroup
        {
            Dock = DockStyle.Fill,
            HeaderStylePrimary = HeaderStyle.Panel
        };
        themeGroup.HeaderPrimary.Content.ShortText = "Theme Settings";

        var themeLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 2,
            RowCount = 2,
            Dock = DockStyle.Fill,
            Padding = new Padding(10)
        };

        // Theme label
        var themeLabel = new KryptonLabel
        {
            Text = "Application Theme:",
            Dock = DockStyle.Fill,
            LabelStyle = LabelStyle.NormalControl
        };

        // Theme combo box
        themeComboBox = new KryptonThemeComboBox
        {
            Dock = DockStyle.Fill,
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        // Description label
        var descriptionLabel = new KryptonLabel
        {
            Text = "Select a theme for the application interface. Changes will be applied immediately.",
            Dock = DockStyle.Fill,
            LabelStyle = LabelStyle.NormalControl
        };

        // Add to layout
        themeLayout.Controls.Add(themeLabel, 0, 0);
        themeLayout.Controls.Add(themeComboBox, 1, 0);
        themeLayout.Controls.Add(descriptionLabel, 0, 1);
        themeLayout.SetColumnSpan(descriptionLabel, 2);

        themeGroup.Panel.Controls.Add(themeLayout);

        // Buttons
        okButton = new KryptonButton
        {
            Text = "OK",
            DialogResult = DialogResult.OK
        };

        cancelButton = new KryptonButton
        {
            Text = "Cancel",
            DialogResult = DialogResult.Cancel
        };

        // Main layout
        var mainLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 1,
            RowCount = 2,
            Dock = DockStyle.Fill
        };

        mainLayout.RowStyles.Add(new RowStyle(SizeType.Percent, 100F));
        mainLayout.RowStyles.Add(new RowStyle(SizeType.Absolute, 40F));

        mainLayout.Controls.Add(themeGroup, 0, 0);
        
        var buttonLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 2,
            RowCount = 1,
            Dock = DockStyle.Fill
        };

        buttonLayout.Controls.Add(okButton, 0, 0);
        buttonLayout.Controls.Add(cancelButton, 1, 0);

        mainLayout.Controls.Add(buttonLayout, 0, 1);

        Controls.Add(mainLayout);
    }
}

Welcome Wizard Theme Selection

public class WelcomeWizardThemeStep : UserControl
{
    private KryptonThemeComboBox themeComboBox;
    private KryptonLabel descriptionLabel;
    private KryptonPanel previewPanel;

    public WelcomeWizardThemeStep()
    {
        InitializeComponent();
        SetupThemeSelectionStep();
    }

    private void SetupThemeSelectionStep()
    {
        // Description
        descriptionLabel = new KryptonLabel
        {
            Text = "Choose a theme that best suits your preferences. You can change this later in settings.",
            Dock = DockStyle.Top,
            LabelStyle = LabelStyle.TitlePanel,
            TextAlign = ContentAlignment.MiddleCenter
        };

        // Theme selection
        var themeLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 2,
            RowCount = 1,
            Dock = DockStyle.Top
        };

        var themeLabel = new KryptonLabel
        {
            Text = "Theme:",
            Dock = DockStyle.Fill,
            LabelStyle = LabelStyle.NormalControl
        };

        themeComboBox = new KryptonThemeComboBox
        {
            Dock = DockStyle.Fill,
            DropDownStyle = ComboBoxStyle.DropDownList
        };

        themeLayout.Controls.Add(themeLabel, 0, 0);
        themeLayout.Controls.Add(themeComboBox, 1, 0);

        // Preview panel
        previewPanel = new KryptonPanel
        {
            Dock = DockStyle.Fill,
            PanelBackStyle = PaletteBackStyle.PanelClient
        };

        // Add sample controls to preview
        var sampleButton = new KryptonButton
        {
            Text = "Sample Button",
            Location = new Point(50, 50)
        };

        var sampleLabel = new KryptonLabel
        {
            Text = "Sample Label",
            Location = new Point(50, 100)
        };

        previewPanel.Controls.Add(sampleButton);
        previewPanel.Controls.Add(sampleLabel);

        // Main layout
        var mainLayout = new KryptonTableLayoutPanel
        {
            ColumnCount = 1,
            RowCount = 3,
            Dock = DockStyle.Fill
        };

        mainLayout.Controls.Add(descriptionLabel, 0, 0);
        mainLayout.Controls.Add(themeLayout, 0, 1);
        mainLayout.Controls.Add(previewPanel, 0, 2);

        Controls.Add(mainLayout);
    }
}