作者：Niels Penneman 翻译：小新0574
原文链接：http://www.codeproject.com/cs/combobox/ImageCombo_NET.asp
Introduction
When I started programming in .NET, I wondered where the ImageCombo control had gone (I used to program in VB6). The .NET Framework didn't seem to have this functionality built-in, but it's very easy to add it.
当我开始使用.NET编程后，我感到很惊讶，ImageCombo 控件去哪了呢？（我以前使用VB6编程）.NET框架似乎没有内建这个功能，不过要构造它很简单。
Using the code
The 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.
代码由两个类组成：ImageCombo 和 ImageComboItem。如果你想在你的C#代码里使用它们，只要把它们复制到你的工程里就行了；对于其他.NET语言，你只要增加一个对这个类库的引用就行了。（译注：把这两个类编译成dll，在工程里引用就行了）
The control inherits from ComboBox and introduces one new member: the ImageList property, which doesn't require any further explanation. The control is owner drawn and there is a custom drawing method defined, so don't change its DrawMode property if you want to see the images.
这个控件继承自ComboBox ，增加了一个新的成员：ImageList 属性，这不需要多做解释了吧。这个控件是自绘的，控件定义一个自定义的绘制方法，所以如果你想看到图像，就不要改变它的DrawMode属性。
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).
ImageComboItem类继承自Object。你可以设置一个自己的ForeColor ，这个类有一个Mark属性，这个属性决定是否项使用粗体显示。（如果项已经是粗体了，这个属性就不会起作用）。
To add an item to an ImageCombo with text "Icon 0" and image index 0, use the following code:
要增加一个使用文本“Icon 0”和（ImageList里）索引值为0的图像的ImageCombo （项）。使用一下代码：
imageCombo.Items.Add(new ImageComboItem("Icon 0", 0));Code listing: ImageCombo class
using 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.Items[e.Index].GetType() == typeof(ImageComboItem)) { // get item to draw ImageComboItem item = (ImageComboItem) this.Items[e.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.Items[e.Index].ToString(), e.Font, new SolidBrush(e.ForeColor), e.Bounds.Left + imgs.ImageSize.Width, e.Bounds.Top); } base.OnDrawItem (e); } }
}Code listing: ImageComboItem class
using 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; } }} About Niels Penneman
I have learnt to program in VB3 when I was about 10. I also learnt Pascal, I moved on to VB5 and later VB6, tried some Visual J++ (1.1) and I have little knowledge of ANSI C. Nowadays I mostly use VB.NET and C# .NET.
我在大概10岁的时候使用VB3开始学习编程。我也学了Pascal，转移到VB5，然后VB6，尝试了一些Visual J++ (1.1)，我几乎不怎么了解ANSI C。现在我主要使用VB.NET和C#.NET。
I am currently studying science and maths in the last year of secondary education (maybe a weird way to explain it but it's because I don't know how YOUR educational system is organized ).
我现在在学习初中（secondary education）最后一年的自然科学与数学的课程（也许这样解释显得有些奇怪，但是是因为我不知道你们的教育体系是怎样组织的）。
