C# CheckedListBox.BeginUpdate方法代码示例

        public static void Draw( CheckedListBox list )
        {
            list.BeginUpdate();
            list.Items.Clear();

            for (int i=0;i<m_Filters.Count;i++)
            {
                Filter f = (Filter)m_Filters[i];
                list.Items.Add( f );
                list.SetItemChecked( i, f.Enabled );
            }
            list.EndUpdate();
        }

    /// <summary>
    /// Overrides the method used to provide basic behaviour for selecting editor.
    /// Shows our custom control for editing the value.
    /// </summary>
    /// <param name="context">The context of the editing control</param>
    /// <param name="provider">A valid service provider</param>
    /// <param name="value">The current value of the object to edit</param>
    /// <returns>The new value of the object</returns>
    public override object EditValue( ITypeDescriptorContext context, IServiceProvider provider, object value) 
    {
      if( context != null && context.Instance != null && provider != null ) 
      {
        edSvc = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));

        if( edSvc != null ) 
        {         
          // Create a CheckedListBox and populate it with all the enum values
          clb = new CheckedListBox();
          clb.BorderStyle = BorderStyle.FixedSingle;
          clb.CheckOnClick = true;
          clb.MouseDown += new MouseEventHandler(this.OnMouseDown);
          clb.MouseMove += new MouseEventHandler(this.OnMouseMoved);
          clb.DoubleClick += new EventHandler( this.OnDoubleClick );

          tooltipControl = new ToolTip();
          tooltipControl.ShowAlways = true;

          clb.BeginUpdate();

          foreach( string name in Enum.GetNames( context.PropertyDescriptor.PropertyType ) )
          {
            // Get the enum value
            object enumVal = Enum.Parse(context.PropertyDescriptor.PropertyType, name);
            // Get the int value 
            int intVal = (int) Convert.ChangeType(enumVal, typeof(int));
            
            // Get the description attribute for this field
            System.Reflection.FieldInfo fi = context.PropertyDescriptor.PropertyType.GetField(name);
            DescriptionAttribute[] attrs = ( DescriptionAttribute[] ) 
              fi.GetCustomAttributes( typeof( DescriptionAttribute ), false );
            
            BrowsableAttribute[] skipAttr = ( BrowsableAttribute[] )
              fi.GetCustomAttributes( typeof( BrowsableAttribute ), false );

            // if flag must be skip in desiner
            if( skipAttr.Length > 0 && skipAttr[0].Browsable == false ) continue;

            // Store the the description
            string tooltip = ( attrs.Length > 0 ) ? attrs[0].Description : string.Empty;

            // Get the int value of the current enum value (the one being edited)
            int intEdited = ( int )Convert.ChangeType( value, typeof( int ) );

            // show in tooltip int value of flag
            tooltip += "(value: " + intEdited.ToString() + ")";

            // Creates a clbItem that stores the name, the int value and the tooltip
            clbItem item = new clbItem(enumVal.ToString(), intVal, tooltip);

            // Get the checkstate from the value being edited
            bool checkedItem = (intEdited & intVal) > 0;

            // Add the item with the right check state
            clb.Items.Add( item, checkedItem );
          }         
          
          clb.EndUpdate();

          // Show our CheckedListbox as a DropDownControl. 
          // This methods returns only when the dropdowncontrol is closed
          edSvc.DropDownControl( clb );

          // Get the sum of all checked flags
          int result = 0;
          
          foreach( clbItem obj in clb.CheckedItems )
          {
            result += obj.Value;
          }

          // return the right enum value corresponding to the result
          return Enum.ToObject(context.PropertyDescriptor.PropertyType, result);
        }
      }

      return value;
    }

 private void UpdateCheckedList(CheckedListBox list)
 {
     object wasSelected = list.SelectedItem;
      list.BeginUpdate();
      for (int i = 0; i < list.Items.Count; i++)
     list.SetItemChecked(i, ((Item)list.Items[i]).IsVisible);
      list.SelectedItem = wasSelected;
      list.EndUpdate();
 }

    void InitializeCheckedListBox(CheckedListBox box, CheckableSelectableListNodeList list)
    {
      box.BeginUpdate();
      box.Items.Clear();
      for(int i=0;i<list.Count;i++)
      {
        CheckableSelectableListNode node=list[i];
      
        box.Items.Add(node, node.Checked);
        if (node.Selected)
          box.SelectedIndices.Add(i);
      }

      box.EndUpdate();
    }

 private void FillOutDatabaseObjectNames(string cmdName, CheckedListBox clb, DatabaseObjectType objectType)
 {
     string objectName;
     string strCmd = ConfigurationManager.AppSettings[cmdName];
     Database db = DatabaseFactory.CreateDatabase();
     Action beginUpdate = () => clb.BeginUpdate();
     clb.Invoke(beginUpdate);
     using (IDataReader reader = db.ExecuteReader(CommandType.Text, strCmd))
     {
         Action addItem;
         while (reader.Read())
         {
             objectName = reader.GetString(0);
             addItem = () => clb.Items.Add(new ListItem() { Value = objectName, Type = objectType });
             clb.Invoke(addItem);
         }
     }
     Action endUpdate = () => clb.EndUpdate();
     clb.Invoke(endUpdate);
 }

 private void SetAllDatabaseObjectSelected(CheckedListBox dbObjectList, CheckBox chkAll)
 {
     dbObjectList.BeginUpdate();
     for (int i = 0; i < dbObjectList.Items.Count; i++)
     {
         dbObjectList.SetItemChecked(i, chkAll.Checked);
     }
     dbObjectList.EndUpdate();
 }