C#带图标的组合框.doc

Download source and demo project - 14.4 Kb IntroductionWhen I started programming in .NET, I wondered where the ImageCombo control had gone (I used to program in VB6). The .NET Framework didnt seem to have this functionality built-in, but its very easy to add it.Using the codeThe code consists of two classes: ImageCombo and ImageComboItem. If you want to use them in C#, just copy them into your project; for other .NET languages, you can add a reference to the library.The control inherits from ComboBox and introduces one new member: the ImageList property, which doesnt require any further explanation. The control is owner drawn and there is a custom drawing method defined, so dont change its DrawMode property if you want to see the images.The ImageComboItem class inherits from Object. You can set a customForeColor and it has a Mark property which determines if the item is shown in bold font style (does not work if owner font is already bold).To add an item to an ImageCombo with text Icon 0 and image index 0, use the following code:imageCombo.Items.Add(new ImageComboItem(Icon 0, 0);Code listing: ImageCombo classusing System;using System.Drawing;namespace System.Windows.Forms public class ImageCombo : ComboBox private ImageList imgs = new ImageList(); / constructor public ImageCombo() / set draw mode to owner draw this.DrawMode = DrawMode.OwnerDrawFixed; / ImageList property public ImageList ImageList get return imgs; set imgs = value; / customized drawing process protected override void OnDrawItem(DrawItemEventArgs e) / draw background & focus rect e.DrawBackground(); e.DrawFocusRectangle(); / check if it is an item from the Items collection if (e.Index 0) / not an item, draw the text (indented) e.Graphics.DrawString(this.Text, e.Font, new SolidBrush(e.ForeColor), e.Bounds.Left + imgs.ImageSize.Width, e.Bounds.Top); else / check if item is an ImageComboItem if (this.Itemse.Index.GetType() = typeof(ImageComboItem) / get item to draw ImageComboItem item = (ImageComboItem) this.Itemse.Index; / get forecolor & font Color forecolor = (item.ForeColor != Color.FromKnownColor(KnownColor.Transparent) ? item.ForeColor : e.ForeColor; Font font = item.Mark ? new Font(e.Font, FontStyle.Bold) : e.Font; / -1: no image if (item.ImageIndex != -1) / draw image, then draw text next to it this.ImageList.Draw(e.Graphics, e.Bounds.Left, e.Bounds.Top, item.ImageIndex); e.Graphics.DrawString(item.Text, font, new SolidBrush(forecolor), e.Bounds.Left + imgs.ImageSize.Width, e.Bounds.Top); else / draw text (indented) e.Graphics.DrawString(item.Text, font, new SolidBrush(forecolor), e.Bounds.Left + imgs.ImageSize.Width, e.Bounds.Top); else / it is not an ImageComboItem, draw it e.Graphics.DrawString(this.Itemse.Index.ToString(), e.Font, new SolidBrush(e.ForeColor), e.Bounds.Left + imgs.ImageSize.Width, e.Bounds.Top); base.OnDrawItem (e); Code listing: ImageComboItem classusing System;using System.Drawing;namespace System.Windows.Forms public class ImageComboItem : object / forecolor: transparent = inherit private Color forecolor = Color.FromKnownColor( KnownColor.Transparent); private bool mark = false; private int imageindex = -1; private object tag = null; private string text = null; / constructors public ImageComboItem() public ImageComboItem(string Text) text = Text; public ImageComboItem(string Text, int ImageIndex) text = Text; imageindex = ImageIndex; public ImageComboItem(string Text, int ImageIndex, bool Mark) text = Text; imageindex = ImageIndex; mark = Mark; public ImageComboItem(string Text, int ImageIndex, bool Mark, Color ForeColor) text = Text; imageindex = ImageIndex; mark = Mark; forecolor = ForeColor; public ImageComboItem(string Text, int ImageIndex, bool Mark, Color ForeColor, object Tag) text = Text; imageindex = ImageIndex; mark = Mark; forecolor = ForeColor; tag = Tag; / forecolor public Color ForeColor get return forecolor; set forecolor = value; / image index public int ImageIndex get return imageindex; set imageindex = value; / mark (bold) public bool Mark get return mark; set mark = value; / tag public object Tag get return tag; set tag = value; / item text public string Text get return text; set text = value; / ToString() should return item text public override string ToString() return text; 使用方法：using System;using System.Drawing;using System.Collections;using System.ComponentModel;using System.Windows.Forms;namespace Demopublic class MainWindow : System.Windows.Forms.FormMTAThread() static void Main() Application.EnableVisualStyles();Application.DoEvents();Application.Run(new MainWindow();private System.Windows.Forms.ImageCombo imageCombo;private System.Windows.Forms.ImageList imageList;private System.Windows.Forms.ComboBox comboBox;private System.Windows.Forms.ImageCombo imageComboList;private System.Windows.Forms.ImageCombo imageComboSimple;private System.ComponentModel.IContainer components;public MainWindow()InitializeComponent();protected override void Dispose( bool disposing )if( disposing )if(components != null)components.Dispose();base.Dispose( disposing );#region Windows Form Designer generated code/ / Required method for Designer support - do not modify/ the contents of this method with the code editor./ private void InitializeComponent()ponents = new System.ComponentModel.Container();System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(MainWindow);this.imageCombo = new System.Windows.Forms.ImageCombo();this.imageList = new System.Windows.Forms.ImageList(ponents);boBox = new System.Windows.Forms.ComboBox();this.imageComboList = new System.Windows.Forms.ImageCombo();this.imageComboSimple = new System.Windows.Forms.ImageCombo();this.SuspendLayout();/ / imageCombo/ this.imageCombo.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;this.imageCombo.ImageList = this.imageList;this.imageCombo.Location = new System.Drawing.Point(8, 40);this.imageCombo.Name = imageCombo;this.imageCombo.Size = new System.Drawing.Size(160, 22);this.imageCombo.TabIndex = 1;/ / imageList/ this.imageList.ColorDepth = System.Windows.Forms.ColorDepth.Depth32Bit;this.imageList.ImageSize = new System.Drawing.Size(16, 16);this.imageList.ImageStream = (System.Windows.Forms.ImageListStreamer)(resources.GetObject(imageList.ImageStream);this.imageList.TransparentColor = System.Drawing.Color.Transparent;/ / comboBox/ boBox.Location = new System.Drawing.Point(8, 8);boBox.Name = comboBox;boBox.Size = new System.Drawing.Size(160, 21);boBox.TabIndex = 0;boBox.Text = ComboBox;/ / imageComboList/ this.imageComboList.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;this.imageComboList.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;this.imageComboList.ImageList = this.imageList;this.imageComboList.Location = new System.Drawing.Point(8, 72);this.imageComboList.Name = imageComboList;this.imageComboList.Size = new System.Drawing.Size(160, 22);this.imageComboList.TabIndex = 2;/ / imageComboSimple/ this.imageComboSimple.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;this.imageComboSimple.DropDownStyle = System.Windows.Forms.ComboBoxStyle.Simple;this.imageComboSimple.ImageList = this.imageList;this.imageComboSimple.Location = new System.Drawing.Point(8, 104);this.imageComboSimple.Name = imageComboSimple;this.imageComboSimple.Size = new System.Drawing.Size(160, 104);this.imageComboSimple.TabIndex = 3;/ / MainWindow/ this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);this.ClientSize = new System.Drawing.Size(202, 216);this.Controls.Add(this.imageComboSimple);this.Controls.Add(boBox);this.Controls.Add(this.imageCombo);this.Controls.Add(this.imageComboList);this.Font = new System.Drawing.Font(Tahoma, 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, (System.Byte)(0);this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedToolWindow;this.Name = MainWindow;this.Text = Demo;this.Load += new System.EventHandler(this.MainWindow_Load);this.ResumeLayout(false);#endregionprivate void MainWindow_Load(object sender, System.EventArgs e)/ add some items (normal combobox);comboBox.Items.Add(Item);comboBox.Items.Add(new ImageComboItem(You can add ImageComboItems to a