为ComboBox控件添加图片

技术2022-05-11 57

using System; using System.Windows.Forms; using System.Windows.Forms.Design; using System.Drawing; namespace Mengxianhui.ComboBoxEx { class ComboBoxEx : ComboBox { private ImageList imageList; public ImageList ImageList { get {return imageList;} set {imageList = value;} } public ComboBoxEx() { DrawMode = DrawMode.OwnerDrawFixed; } protected override void OnDrawItem(DrawItemEventArgs ea) { ea.DrawBackground(); ea.DrawFocusRectangle(); ComboBoxExItem item; Size imageSize = imageList.ImageSize; Rectangle bounds = ea.Bounds; try { item = (ComboBoxExItem)Items[ea.Index]; if (item.ImageIndex != -1) { imageList.Draw(ea.Graphics, bounds.Left, bounds.Top, item.ImageIndex); ea.Graphics.DrawString(item.Text, ea.Font, new SolidBrush(ea.ForeColor), bounds.Left+imageSize.Width, bounds.Top); } else { ea.Graphics.DrawString(item.Text, ea.Font, new SolidBrush(ea.ForeColor), bounds.Left, bounds.Top); } } catch { if (ea.Index != -1) { ea.Graphics.DrawString(Items[ea.Index].ToString(), ea.Font, new SolidBrush(ea.ForeColor), bounds.Left, bounds.Top); } else { ea.Graphics.DrawString(Text, ea.Font, new SolidBrush(ea.ForeColor), bounds.Left, bounds.Top); } } base.OnDrawItem(ea); } } class ComboBoxExItem { private string _text; public string Text { get {return _text;} set {_text = value;} } private int _imageIndex; public int ImageIndex { get {return _imageIndex;} set {_imageIndex = value;} } public ComboBoxExItem() : this("") { } public ComboBoxExItem(string text) : this(text, -1) { } public ComboBoxExItem(string text, int imageIndex) { _text = text; _imageIndex = imageIndex; } 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; using System.Data; namespace Mengxianhui.ComboBoxEx { /// <summary> /// Summary description for Form1. /// </summary> public class Form1 : System.Windows.Forms.Form { private ComboBoxEx comboBox1; private System.ComponentModel.IContainer components; public Form1() { // // Required for Windows Form Designer support // InitializeComponent(); // // TODO: Add any constructor code after InitializeComponent call // } /// <summary> /// Clean up any resources being used. /// </summary> protected override void Dispose( bool disposing ) { if( disposing ) { if (components != null) { components.Dispose(); } } base.Dispose( disposing ); } Windows Form Designer generated code /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { Application.Run(new Form1()); } }}

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