ComboBoxRenderer.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / ComboBoxRenderer.cs / 1 / ComboBoxRenderer.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 
namespace System.Windows.Forms {
 
    using System; 
    using System.Drawing;
    using System.Diagnostics.CodeAnalysis; 
    using System.Windows.Forms.Internal;
    using System.Windows.Forms.VisualStyles;
    using Microsoft.Win32;
 

    ///  
    ///  
    ///    
    ///       This is a rendering class for the ComboBox control. 
    ///    
    /// 
    public sealed class ComboBoxRenderer {
 
        //Make this per-thread, so that different threads can safely use these methods.
        [ThreadStatic] 
        private static VisualStyleRenderer visualStyleRenderer = null; 
        private static readonly VisualStyleElement ComboBoxElement = VisualStyleElement.ComboBox.DropDownButton.Normal;
        private static readonly VisualStyleElement TextBoxElement = VisualStyleElement.TextBox.TextEdit.Normal; 

        //cannot instantiate
        private ComboBoxRenderer() {
        } 

        ///  
        ///  
        ///    
        ///       Returns true if this class is supported for the current OS and user/application settings, 
        ///       otherwise returns false.
        ///    
        /// 
        public static bool IsSupported { 
            get {
                return VisualStyleRenderer.IsSupported; // no downlevel support 
            } 
        }
 
        private static void DrawBackground(Graphics g, Rectangle bounds, ComboBoxState state) {
            visualStyleRenderer.DrawBackground(g, bounds);
            //for disabled comboboxes, comctl does not use the window backcolor, so
            // we don't refill here in that case. 
            if (state != ComboBoxState.Disabled) {
                Color windowColor = visualStyleRenderer.GetColor(ColorProperty.FillColor); 
                if (windowColor != SystemColors.Window) { 
                    Rectangle fillRect = visualStyleRenderer.GetBackgroundContentRectangle(g, bounds);
                    fillRect.Inflate(-2, -2); 
                    //then we need to re-fill the background.
                    g.FillRectangle(SystemBrushes.Window, fillRect);
                }
            } 
        }
 
        ///  
        /// 
        ///     
        ///       Renders the textbox part of a ComboBox control.
        ///    
        /// 
        [ 
            SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters") // Using Graphics instead of IDeviceContext intentionally
        ] 
        public static void DrawTextBox(Graphics g, Rectangle bounds, ComboBoxState state) { 
            if (visualStyleRenderer == null) {
                visualStyleRenderer = new VisualStyleRenderer(TextBoxElement.ClassName, TextBoxElement.Part, (int)state); 
            }
            else {
                visualStyleRenderer.SetParameters(TextBoxElement.ClassName, TextBoxElement.Part, (int)state);
            } 

            DrawBackground(g, bounds, state); 
        } 

        ///  
        /// 
        ///    
        ///       Renders the textbox part of a ComboBox control.
        ///     
        /// 
        public static void DrawTextBox(Graphics g, Rectangle bounds, string comboBoxText, Font font, ComboBoxState state) { 
            DrawTextBox(g, bounds, comboBoxText, font, TextFormatFlags.TextBoxControl, state); 
        }
 
        /// 
        /// 
        ///    
        ///       Renders the textbox part of a ComboBox control. 
        ///    
        ///  
        public static void DrawTextBox(Graphics g, Rectangle bounds, string comboBoxText, Font font, Rectangle textBounds, ComboBoxState state) { 
            DrawTextBox(g, bounds, comboBoxText, font, textBounds, TextFormatFlags.TextBoxControl, state);
        } 

        /// 
        /// 
        ///     
        ///       Renders the textbox part of a ComboBox control.
        ///     
        ///  
        public static void DrawTextBox(Graphics g, Rectangle bounds, string comboBoxText, Font font, TextFormatFlags flags, ComboBoxState state) {
            if (visualStyleRenderer == null) { 
                visualStyleRenderer = new VisualStyleRenderer(TextBoxElement.ClassName, TextBoxElement.Part, (int)state);
            }
            else {
                visualStyleRenderer.SetParameters(TextBoxElement.ClassName, TextBoxElement.Part, (int)state); 
            }
 
            Rectangle textBounds = visualStyleRenderer.GetBackgroundContentRectangle(g, bounds); 
            textBounds.Inflate(-2,-2);
            DrawTextBox(g, bounds, comboBoxText, font, textBounds, flags, state); 
        }

        /// 
        ///  
        ///    
        ///       Renders the textbox part of a ComboBox control. 
        ///     
        /// 
        [ 
            SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters") // Using Graphics instead of IDeviceContext intentionally
        ]
        public static void DrawTextBox(Graphics g, Rectangle bounds, string comboBoxText, Font font, Rectangle textBounds, TextFormatFlags flags, ComboBoxState state) {
            if (visualStyleRenderer == null) { 
                visualStyleRenderer = new VisualStyleRenderer(TextBoxElement.ClassName, TextBoxElement.Part, (int)state);
            } 
            else { 
                visualStyleRenderer.SetParameters(TextBoxElement.ClassName, TextBoxElement.Part, (int)state);
            } 

            DrawBackground(g, bounds, state);
            Color textColor = visualStyleRenderer.GetColor(ColorProperty.TextColor);
            TextRenderer.DrawText(g, comboBoxText, font, textBounds, textColor, flags); 
        }
 
        ///  
        /// 
        ///     
        ///       Renders a ComboBox drop-down button.
        ///    
        /// 
        [ 
            SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters") // Using Graphics instead of IDeviceContext intentionally
        ] 
        public static void DrawDropDownButton(Graphics g, Rectangle bounds, ComboBoxState state) { 
            if (visualStyleRenderer == null) {
                visualStyleRenderer = new VisualStyleRenderer(ComboBoxElement.ClassName, ComboBoxElement.Part, (int)state); 
            }
            else {
                visualStyleRenderer.SetParameters(ComboBoxElement.ClassName, ComboBoxElement.Part, (int)state);
            } 

            visualStyleRenderer.DrawBackground(g, bounds); 
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ComboBoxRenderer.cs source code in C# .NET

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