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通过

ISelectionService 接口

  • 参考

定义

命名空间:
System.ComponentModel.Design
程序集:
System.ComponentModel.TypeConverter.dll
程序集:
System.dll
程序集:
netstandard.dll

为设计器提供用于选择组件的接口。

public interface ISelectionService
[System.Runtime.InteropServices.ComVisible(true)]
public interface ISelectionService
属性
ComVisibleAttribute

示例

以下示例演示如何使用 ISelectionService 来处理 SelectionChanged 和 SelectionChanging 事件。

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Windows.Forms;

/*  This sample demonstrates using the ISelectionService
    interface to receive notification of selection change events.  
    The SelectionComponent control attempts to retrieve an instance 
    of the ISelectionService when it is sited. If it can, it attaches 
    event handlers for events provided by the service that display
    a message when a component is selected or deselected.

    To run this sample, add the SelectionComponent control to a Form and
    then select or deselect components in design mode to see the behavior 
    of the component change event handlers. */

namespace ISelectionServiceExample 
{
    public class SelectionComponent : System.Windows.Forms.UserControl 
    {		
        private System.Windows.Forms.TextBox tbox1;
        private ISelectionService selectionService;
        
        public SelectionComponent() 
        {
            // Initialize control
            this.SuspendLayout();			
            this.Name = "SelectionComponent";
            this.Size = new System.Drawing.Size(608, 296);									
            this.tbox1 = new System.Windows.Forms.TextBox();			
            this.tbox1.Location = new System.Drawing.Point(24, 16);
            this.tbox1.Name = "listBox1";
            this.tbox1.Multiline = true;
            this.tbox1.Size = new System.Drawing.Size(560, 251);
            this.tbox1.TabIndex = 0;
            this.Controls.Add(this.tbox1);
            this.ResumeLayout();
        }
        
        public override ISite Site 
        {
            get 
            {
                return base.Site;
            }
            set 
            {
                // The ISelectionService is available in design mode 
                // only, and only after the component is sited.
                if (selectionService != null) 
                {
                    // Because the selection service has been 
                    // previously obtained, the component may be in 
                    // the process of being resited. 
                    // Detatch the previous selection change event 
                    // handlers in case the new selection
                    // service is a new service instance belonging to 
                    // another design mode service host.
                    selectionService.SelectionChanged -= new EventHandler(OnSelectionChanged);
                    selectionService.SelectionChanging -= new EventHandler(OnSelectionChanging);
                }

                // Establish the new site for the component.
                base.Site = value;				

                if( base.Site == null )
                    return;

                // The selection service is not available outside of 
                // design mode. A call requesting the service 
                // using GetService while not in design mode will 
                // return null.
                selectionService = (ISelectionService)this.Site.GetService(typeof(ISelectionService));

                // If an instance of the ISelectionService was obtained, 
                // attach event handlers for the selection 
                // changing and selection changed events.
                if (selectionService != null)
                {
                    // Add an event handler for the SelectionChanging 
                    // and SelectionChanged events.
                    selectionService.SelectionChanging += new EventHandler(OnSelectionChanging);					
                    selectionService.SelectionChanged += new EventHandler(OnSelectionChanged);	
                }
            }
        }
        
        private void OnSelectionChanged(object sender, EventArgs args)
        {						
            tbox1.AppendText("The selected component was changed.  Selected components:\r\n    " + GetSelectedComponents() + "\r\n");
        }
        
        private void OnSelectionChanging(object sender, EventArgs args)
        {
            tbox1.AppendText("The selected component is changing. Selected components:\r\n    " + GetSelectedComponents() + "\r\n");			
        }
        
        private string GetSelectedComponents()
        {
            string selectedString = String.Empty;
            object[] components = new object[((ICollection)selectionService.GetSelectedComponents()).Count];
            ((ICollection)selectionService.GetSelectedComponents()).CopyTo(components, 0);

            for(int i=0; i<components.Length; i++)
            {
                if( i != 0 )
                    selectedString += "&& ";
                if( ((IComponent)selectionService.PrimarySelection) == ((IComponent)components[i]) )
                    selectedString += "PrimarySelection:";				
                selectedString += ((IComponent)components[i]).Site.Name+" ";
            }
            return selectedString;
        }
        
        // Clean up any resources being used.
        protected override void Dispose( bool disposing )
        {
            // Detatch the event handlers for the selection service.
            if( selectionService != null )
            {
                selectionService.SelectionChanging -= new EventHandler(this.OnSelectionChanging);
                selectionService.SelectionChanged -= new EventHandler(this.OnSelectionChanged);
            }

            base.Dispose( disposing );
        }
    }
}

注解

选择组件后，其可查看或可编辑属性将显示在属性窗口中。

属性

PrimarySelection

获取当前为主选定对象的对象。
SelectionCount

获取选定对象的计数。

方法

GetComponentSelected(Object)

获取一个值，该值指示当前是否选定指定组件。
GetSelectedComponents()

获取当前选定的组件的集合。
SetSelectedComponents(ICollection)

选择指定的组件集合。
SetSelectedComponents(ICollection, SelectionTypes)

从匹配指定选择类型的指定组件集合中选择组件。

事件

SelectionChanged

当前所选内容更改时发生。
SelectionChanging

在将要更改当前选择时发生。

适用于