Question

winform设计时 怎么在下拉框中添加图片呢？请知道的人帮一下忙哈！

Answer 1

ComboBox With Images
By Rakka Rage

There is no built in support for a ComboBox with images. So i created a simple ComboBoxEx class that derives from ComboBox and allows you to set the ComboBoxEx.ImageList property and ComboBoxExItem.ImageIndex property so that the ComboBox displays an image.

...
ComboBoxEx comboBox = new ComboBoxEx();
comboBox.ImageList = imageList;
// not needed but... no icon for index -1 else
comboBox.DropDownStyle = ComboBoxStyle.DropDownList;
// just pass these in instead of strings, class included below
// specify a valid imageIndex
comboBox.Items.Add(new ComboBoxExItem( "Text0 ", 0));
comboBox.Items.Add(new ComboBoxExItem( "Text1 ", 1));

Code:
namespace Rage.Library
{
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;
}
}
}

追问

请问这是做组件吗？我是初学者，可以说的详细些么？谢谢啦！

追答

不是组件,新建一个类 class ComboBoxEx : ComboBox，看这里，继承ComboBox，然后在ComboBoxEx 封装 ComboBox的一些属性值。 protected override void OnDrawItem这个方法是重绘ComboBox的下拉选择框。具体效果需要你耐心 的去测试一下！测试成功了说明你懂了，光把代码帖上去也没多大意思