ComboBoxDesigner.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Designer / WinForms / System / WinForms / Design / ComboBoxDesigner.cs / 1 / ComboBoxDesigner.cs
                        
                        
                             
//------------------------------------------------------------------------------
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
//  
//-----------------------------------------------------------------------------
 
/* 
 */
[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode", Scope="member", Target="System.Windows.Forms.Design.ComboBoxDesigner..ctor()")] 

namespace System.Windows.Forms.Design {
    using System;
    using System.Collections; 
    using System.ComponentModel;
    using System.ComponentModel.Design; 
    using System.Windows.Forms.Design.Behavior; 

    ///  
    /// 
    ///    
    ///       Provides a designer that can design components
    ///       that extend ComboBox. 
    /// 
    internal class ComboBoxDesigner : ControlDesigner { 
 
        private EventHandler propChanged = null; // Delegate used to dirty the selectionUIItem when needed.
        private DesignerActionListCollection _actionLists; 

        /// 
        /// 
        ///     Adds a baseline SnapLine to the list of SnapLines related 
        ///     to this control.
        ///  
        public override IList SnapLines { 
            get {
                ArrayList snapLines = base.SnapLines as ArrayList; 

                //a single text-baseline for the label (and linklabel) control
                int baseline = DesignerUtils.GetTextBaseline(Control, System.Drawing.ContentAlignment.TopLeft);
                baseline += 3; 
                snapLines.Add(new SnapLine(SnapLineType.Baseline, baseline, SnapLinePriority.Medium));
 
                return snapLines; 
            }
        } 

        /// 
        /// 
        ///      Disposes of this object. 
        /// 
        protected override void Dispose(bool disposing) { 
            if (disposing) { 
                // Hook up the property change notification so that we can dirty the SelectionUIItem when needed.
                if (propChanged != null) { 
                    ((ComboBox)Control).StyleChanged -= propChanged;
                }
            }
 
            base.Dispose(disposing);
        } 
 
        /// 
        ///  
        ///     Called by the host when we're first initialized.
        /// 
        public override void Initialize(IComponent component) {
            base.Initialize(component); 

            AutoResizeHandles = true; 
 
            // Hook up the property change notification so that we can dirty the SelectionUIItem when needed.
            propChanged = new EventHandler(this.OnControlPropertyChanged); 
            ((ComboBox)Control).StyleChanged += propChanged;
        }

        ///  
        /// 
        ///   We override this so we can clear the text field set by controldesigner. 
        ///  
        public override void InitializeNewComponent(IDictionary defaultValues) {
            base.InitializeNewComponent(defaultValues); 

            // in Whidbey, formattingEnabled is TRUE
            ((ComboBox) this.Component).FormattingEnabled = true;
 
            PropertyDescriptor textProp = TypeDescriptor.GetProperties(Component)["Text"];
            if (textProp != null && textProp.PropertyType == typeof(string) && !textProp.IsReadOnly && textProp.IsBrowsable) { 
                textProp.SetValue(Component, ""); 
            }
        } 

        /// 
        /// 
        ///      For controls, we sync their property changed event so our component can track their location. 
        /// 
        private void OnControlPropertyChanged(object sender, EventArgs e) { 
            if (BehaviorService != null) { 
                BehaviorService.SyncSelection();
            } 
        }

        /// 
        ///  
        ///     Retrieves a set of rules concerning the movement capabilities of a component.
        ///     This should be one or more flags from the SelectionRules class.  If no designer 
        ///     provides rules for a component, the component will not get any UI services. 
        /// 
        public override SelectionRules SelectionRules { 
            get {
                SelectionRules rules = base.SelectionRules;
                object component = Component;
 
                PropertyDescriptor propStyle = TypeDescriptor.GetProperties(component)["DropDownStyle"];
                if (propStyle != null) { 
                    ComboBoxStyle style = (ComboBoxStyle)propStyle.GetValue(component); 

                    // Height is not user-changable for these styles 
                    if (style == ComboBoxStyle.DropDown || style == ComboBoxStyle.DropDownList)
                        rules &= ~(SelectionRules.TopSizeable | SelectionRules.BottomSizeable);
                }
 
                return rules;
            } 
        } 

 
        public override DesignerActionListCollection ActionLists {
            get {
                if (_actionLists == null) {
                    _actionLists = new DesignerActionListCollection(); 
                    _actionLists.Add(new ListControlBoundActionList(this));
                } 
                return _actionLists; 
            }
        } 
    }
}

 

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

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