日期:2008-10-16  浏览次数:20441 次

 

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