UI类型编辑器

当你在制作组件时遇到难以构造，解释的或者取值过多，比较复杂的或者难以用一个字符串来表示的视觉效果属性时，你需要实现UI类型编辑器。常见属性ForeColor属性就是一个很好的例子，这种可视化编辑风格使得属性值的选择更方便，更美观！

实现一个定制的UI编辑器：

1.从UITypeEditor基类派生一个新类。

2.对继承自基类的GetEditStyle和EditValue方法进行覆盖。

具体实现：

1.访问属性浏览器的UI显示服务IWindowsFormsEditorService。

2.创建该编辑器UI实现的一个实例。

3.把当前属性的值传递给你在第2步创建的UI编辑器控件。

4.请求属性浏览器显示这个UI编辑器控件。

5.选择一个新的属性值并关闭这个UI编辑器控件。

6.从这个编辑器返回，返回值就是你在第5步选择的新属性值。

还是以ClockControl为例（参考前文：《.Net窗体设计阶段的功能集成问答》和《类型转换器的定制》，附源代码），为它的Face属性提供一个下拉式编辑器：

 1  public class FaceEditor : System.Drawing.Design.UITypeEditor {
 2    public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context) {
 3      if( context != null ) {
 4        return UITypeEditorEditStyle.DropDown;
 5      }
 6      return base.GetEditStyle(context);
 7    }
 8    public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value) {
 9
      if( (context != null) && (provider != null) ) {
        // Access the property browser抯 UI display service, IWindowsFormsEditorService
        IWindowsFormsEditorService   editorService = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));

        if( editorService != null ) {
          // Create an instance of the UI editor control, passing a reference to the editor service
          FaceEditorControl   dropDownEditor = new FaceEditorControl(editorService);

          // Pass the UI editor control the current property value
          dropDownEditor.Face = (ClockFace)value;

          // Display the UI editor control
          editorService.DropDownControl(dropDownEditor);

          // Return the new property value from the UI editor control
          return dropDownEditor.Face;
        }
      }
      return base.EditValue(context, provider, value);
    }
  }

  1/**//// <summary>
  2    /// Summary description for FaceEditorControl.
  3    /// </summary>
  4    internal class FaceEditorControl : System.Windows.Forms.UserControl  {
  5    private System.Windows.Forms.PictureBox picDigital;
  6    private System.Windows.Forms.PictureBox picAnalog;
  7    private System.Windows.Forms.PictureBox picBoth;
  8        /**//// <summary> 
  9        /// Required designer variable.
 10        /// </summary>
 11        private System.ComponentModel.Container components = null;
 12
 13        public FaceEditorControl()
 14        {
 15            // This call is required by the Windows.Forms Form Designer.
 16            InitializeComponent();
 17
 18            // TODO: Add any initialization after the InitForm call
 19
 20        }
 21
 22        /**//// <summary> 
 23        /// Clean up any resources being used.
 24        /// </summary>
 25        protected override void Dispose( bool disposing )
 26        {
 27            if( disposing )
 28            {
 29                if(components != null)
 30                {
 31                    components.Dispose();
 32                }
 33            }
 34            base.Dispose( disposing );
 35        }
 36
 37        Component Designer generated code#region Component Designer generated code
 38        /**//// <summary> 
 39        /// Required method for Designer support - do not modify 
 40        /// the contents of this method with the code editor.
 41        /// </summary>
 42        private void InitializeComponent()
 43        {
 44      System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(FaceEditorControl));
 45      this.picDigital = new System.Windows.Forms.PictureBox();
 46      this.picAnalog = new System.Windows.Forms.PictureBox();
 47      this.picBoth = new System.Windows.Forms.PictureBox();
 48      this.SuspendLayout();
 49      // 
 50      // picDigital
 51      // 
 52      this.picDigital.BackColor = System.Drawing.SystemColors.Highlight;
 53      this.picDigital.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
 54      this.picDigital.Image = ((System.Drawing.Bitmap)(resources.GetObject("picDigital.Image")));
 55      this.picDigital.Location = new System.Drawing.Point(152, 8);
 56      this.picDigital.Name = "picDigital";
 57      this.picDigital.Size = new System.Drawing.Size(65, 65);
 58      this.picDigital.TabIndex = 8;
 59      this.picDigital.TabStop = false;
 60      this.picDigital.Click += new System.EventHandler(this.picDigital_Click);
 61      // 
 62      // picAnalog
 63      // 
 64      this.picAnalog.BackColor = System.Drawing.SystemColors.Highlight;
 65      this.picAnalog.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
 66      this.picAnalog.Image = ((System.Drawing.Bitmap)(resources.GetObject("picAnalog.Image")));
 67      this.picAnalog.Location = new System.Drawing.Point(80, 8);
 68      this.picAnalog.Name = "picAnalog";
 69      this.picAnalog.Size = new System.Drawing.Size(65, 65);
 70      this.picAnalog.TabIndex = 7;
 71      this.picAnalog.TabStop = false;
 72      this.picAnalog.Click += new System.EventHandler(this.picAnalog_Click);
 73      // 
 74      // picBoth
 75      // 
 76      this.picBoth.BackColor = System.Drawing.SystemColors.Highlight;
 77      this.picBoth.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
 78      this.picBoth.Image = ((System.Drawing.Bitmap)(resources.GetObject("picBoth.Image")));
 79      this.picBoth.Location = new System.Drawing.Point(8, 8);
 80      this.picBoth.Name = "picBoth";
 81      this.picBoth.Size = new System.Drawing.Size(65, 65);
 82      this.picBoth.TabIndex = 6;
 83      this.picBoth.TabStop = false;
 84      this.picBoth.Click += new System.EventHandler(this.picBoth_Click);
 85      // 
 86      // FaceEditorControl
 87      // 
 88      this.BackColor = System.Drawing.Color.FromArgb(((System.Byte)(236)), ((System.Byte)(233)), ((System.Byte)(216)));
 89      this.Controls.AddRange(new System.Windows.Forms.Control[] {
 90                                                                  this.picDigital,
 91                                                                  this.picAnalog,
 92                                                                  this.picBoth});
 93      this.Name = "FaceEditorControl";
 94      this.Size = new System.Drawing.Size(223, 80);
 95      this.ResumeLayout(false);
 96
 97    }
 98        #endregion
 99
    private ClockFace                   face = ClockFace.Both;
    private IWindowsFormsEditorService  editorService = null;

    public FaceEditorControl(IWindowsFormsEditorService editorService) {
      InitializeComponent();
      this.editorService = editorService;
    }

    public ClockFace Face {
      get { return face; }
      set { 
        face = value;
        if( face == ClockFace.Both ) {
          this.picBoth.BackColor = Color.Red;
          return;
        }
        if( face == ClockFace.Analog ) {
          this.picAnalog.BackColor = Color.Red;
          return;
        }
        if( face == ClockFace.Digital ) {
          this.picDigital.BackColor = Color.Red;
          return;
        }
      }
    }

    private void picBoth_Click(object sender, System.EventArgs e) {
      face = ClockFace.Both;

      // Close the UI editor upon value selection
      editorService.CloseDropDown();
    }

    private void picAnalog_Click(object sender, System.EventArgs e) {
      face = ClockFace.Analog;

      // Close the UI editor upon value selection
      editorService.CloseDropDown();
    }

    private void picDigital_Click(object sender, System.EventArgs e) {
      face = ClockFace.Digital;

      // Close the UI editor upon value selection
      editorService.CloseDropDown();
    }

    protected override void OnPaint(PaintEventArgs pe) {

      // Get currently selected control
      PictureBox   selected;
      if( face == ClockFace.Both ) selected = this.picBoth;
      else if( face == ClockFace.Analog ) selected = this.picAnalog;
      else selected = this.picDigital;

      // Paint the border
      Graphics   g = pe.Graphics;
      using( Pen pen = new Pen(Color.Gray, 1) ) {
        pen.DashStyle = DashStyle.Dash;
        g.DrawLine( pen, new Point(selected.Left - 2, selected.Top - 2), new Point(selected.Left + selected.Width + 1, selected.Top - 2));
        g.DrawLine( pen, new Point(selected.Left + selected.Width + 1, selected.Top - 2), new Point(selected.Left + selected.Width + 1, selected.Top + selected.Height + 1));
        g.DrawLine( pen, new Point(selected.Left + selected.Width + 1, selected.Top + selected.Height + 1), new Point(selected.Left - 2, selected.Top + selected.Height + 1));
        g.DrawLine( pen, new Point(selected.Left - 2, selected.Top + selected.Height + 1), new Point(selected.Left - 2, selected.Top - 2));
      }
      base.OnPaint(pe);
    }
    }