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public partial class B_ComboBox : ComboBox { public B_ComboBox() { InitializeComponent(); this.DrawMode = DrawMode.OwnerDrawFixed; //this.DrawItem += new System.Windows.Forms.DrawItemEventHandler(this.ListBox_DrawItem); } #region 变量 private static Brush[] listBoxBrushes; //该数组用来存储绘制listBox1背景的Brush对象 private static int place = -1; //颜色位置的取值 private static bool naught = true; //判断是否重绘 #endregion #region 属性 private bool TGradualC = false; [Browsable(true), Category("控件的重绘设置"), Description("判断是否进行渐变色的设置")] //在“属性”窗口中显示DataStyle属性 public bool GradualC { get { return TGradualC; } set { TGradualC = value; this.Invalidate(); } } private Color TColorSelect = Color.Gainsboro; [Browsable(true), Category("控件的重绘设置"), Description("项被选中后的高亮度颜色")] //在“属性”窗口中显示DataStyle属性 public Color ColorSelect { get { return TColorSelect; } set { TColorSelect = value; this.Invalidate(); } } private Color TColor1 = Color.CornflowerBlue; [Browsable(true), Category("控件的重绘设置"), Description("第一个颜色的设置")] //在“属性”窗口中显示DataStyle属性 public Color Color1 { get { return TColor1; } set { TColor1 = value; this.Invalidate(); } } private Color TColor1Gradual = Color.Thistle; [Browsable(true), Category("控件的重绘设置"), Description("第一个颜色的渐变色设置")] //在“属性”窗口中显示DataStyle属性 public Color Color1Gradual { get { return TColor1Gradual; } set { TColor1Gradual = value; this.Invalidate(); } } private Color TColor2 = Color.PaleGreen; [Browsable(true), Category("控件的重绘设置"), Description("第二个颜色的设置")] //在“属性”窗口中显示DataStyle属性 public Color Color2 { get { return TColor2; } set { TColor2 = value; this.Invalidate(); } } private Color TColor2Gradual = Color.DarkKhaki; [Browsable(true), Category("控件的重绘设置"), Description("第二个颜色的渐变色设置")] //在“属性”窗口中显示DataStyle属性 public Color Color2Gradual { get { return TColor2Gradual; } set { TColor2Gradual = value; this.Invalidate(); } } #endregion private void B_ComboBox_DrawItem(object sender, DrawItemEventArgs e) { Rectangle r = new Rectangle(0, 0, this.Width, this.Height); //设置重绘的区域 SolidBrush SolidB1 = new SolidBrush(this.Color1); //设置上一行颜色 SolidBrush SolidB2 = new SolidBrush(this.Color2); //设置下一行颜色 //设置上一行的渐变色 LinearGradientBrush LinearG1 = new LinearGradientBrush(r, this.Color1, this.Color1Gradual, LinearGradientMode.BackwardDiagonal); //设置下一行的渐变色 LinearGradientBrush LinearG2 = new LinearGradientBrush(r, this.Color2, this.Color2Gradual, LinearGradientMode.BackwardDiagonal); //将单色与渐变色存入Brush数组中 listBoxBrushes = new Brush[] {SolidB1, LinearG1, SolidB2, LinearG2}; if (this.Items.Count <= 0) //如果当前控件为空 return; if (e.Index == (this.Items.Count - 1)) //如果绘制的是最后一个项 { bool tem_bool = true; if (e.Index == 0 && tem_bool) //如果当前绘制的是第一个或最后一个项 naught = false; //不进行重绘 } if (naught) //对控件进行重绘 { //获取当前绘制的颜色值 Brush brush = listBoxBrushes[ place = (GradualC) ? (((e.Index % 2) == 0) ? 1 : 3) : (((e.Index % 2) == 0) ? 0 : 2)]; //用指定的画刷填充列表项范围所形成的矩形 e.Graphics.FillRectangle(brush, e.Bounds); //判断当前项是否被选取中 bool selected = ((e.State & DrawItemState.Selected) == DrawItemState.Selected) ? true : false; if (selected) //如果当前项被选中 { e.Graphics.FillRectangle(new SolidBrush(ColorSelect), e.Bounds); //绘制当前项 } //绘制当前项中的文本 e.Graphics.DrawString(this.Items[e.Index].ToString(), this.Font, Brushes.Black, e.Bounds); } e.DrawFocusRectangle(); //绘制聚焦框 } } |
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原文链接：https://zhima.blog.csdn.net/article/details/128101726
