combobox控件|下拉
前不久，有位朋友发帖，寻求颜色选择的COMBOBOX 的制作方法，经过试验，整理了出来，仅供参考。
（注：如有引用，请注明出处和作者）
--闵峰（2005/08/06东莞）
Private Sub filllistboxwithcolors()
Me.ComboBox1.DrawMode = DrawMode.OwnerDrawFixed
Me.ComboBox1.DropDownStyle = ComboBoxStyle.DropDownList
Me.ComboBox1.ItemHeight = 15
'避免闪烁beginupdate
Me.ComboBox1.BeginUpdate()
ComboBox1.Items.Clear()
Dim pi As Reflection.PropertyInfo
For Each pi In GetType(Color).GetProperties(Reflection.BindingFlags.Public Or Reflection.BindingFlags.Static)
Me.ComboBox1.Items.Add(pi.Name)
Next
ComboBox1.EndUpdate()
End Sub
Private Sub ComboBox1_DrawItem(ByVal sender As Object, ByVal e As System.Windows.Forms.DrawItemEventArgs) Handles ComboBox1.DrawItem
If e.Index < 0 Then Exit Sub
Dim rect As Rectangle = e.Bounds '每一项的边框
'绘制项如果被选中则显示高亮显示背景,否则用白色
If e.State And DrawItemState.Selected Then
e.Graphics.FillRectangle(SystemBrushes.Highlight, rect)
Else
e.Graphics.FillRectangle(SystemBrushes.Window, rect)
End If
Dim colorname As String = ComboBox1.Items(e.Index)
Dim b As New SolidBrush(Color.FromName(colorname))
'缩小选定项区域()
rect.Inflate(-16, -2)
'填充颜色(文字对应的颜色)
e.Graphics.FillRectangle(b, rect)
'绘制边框()
e.Graphics.DrawRectangle(Pens.Black, rect)
Dim b2 As Brush
'确定显示的文字的颜色()
If CInt(b.Color.R) + CInt(b.Color.G) + CInt(b.Color.B) > 128 * 3 Then
b2 = Brushes.Black
Else
b2 = Brushes.White
End If
e.Graphics.DrawString(colorname, Me.ComboBox1.Font, b2, rect.X, rect.Y)
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
filllistboxwithcolors()
End Sub