如何给CheckBoxList和RadioButtonList添加滚动条？
继承基类CheckBoxList和RadioButtonList，添加滚动属性，重写Render方法即可。
属性列表：
#region 滚动控制 private bool _ShowScrollBar = false; /// <summary> /// 显示滚动条 /// </summary> [ System.ComponentModel.Description("是否显示显示滚动条") , System.ComponentModel.DefaultValue(false) , System.ComponentModel.Category("滚动条设置") , System.ComponentModel.Bindable(System.ComponentModel.BindableSupport.Yes) ] public bool ShowScrollBar { get { return _ShowScrollBar; } set { _ShowScrollBar = value; } } private Overflow _OverflowY = Overflow.auto; /// <summary> /// 竖直滚动条 /// </summary> [ System.ComponentModel.Description("竖直滚动条") , System.ComponentModel.DefaultValue(Overflow.auto) , System.ComponentModel.Category("滚动条设置") , System.ComponentModel.Bindable(System.ComponentModel.BindableSupport.Yes) ] public Overflow OverflowY { get { return _OverflowY; } set { _OverflowY = value; } } private Overflow _OverflowX = Overflow.auto; /// <summary> /// 水平滚动条 /// </summary> [ System.ComponentModel.Description("水平滚动条") , System.ComponentModel.DefaultValue(Overflow.auto) , System.ComponentModel.Category("滚动条设置") , System.ComponentModel.Bindable(System.ComponentModel.BindableSupport.Yes) ] public Overflow OverflowX { get { return _OverflowX; } set { _OverflowX = value; } } private Unit _ScrollHeight = Unit.Parse("0px"); /// <summary> /// 滚动高度 /// </summary> [ System.ComponentModel.Description("滚动高度") , System.ComponentModel.Category("滚动条设置") , DefaultValue("0px") , System.ComponentModel.Bindable(System.ComponentModel.BindableSupport.Yes) ] public Unit ScrollHeight { get { return _ScrollHeight; } set { _ScrollHeight = value; } } private Unit _ScrollWidth = Unit.Parse("0px"); /// <summary> /// 滚动宽度 /// </summary> [ System.ComponentModel.Description("滚动宽度") , System.ComponentModel.Category("滚动条设置") , DefaultValue("0px") , System.ComponentModel.Bindable(System.ComponentModel.BindableSupport.Yes) ] public Unit ScrollWidth { get { return _ScrollWidth; } set { _ScrollWidth = value; } } private string _ScrollCssClass = ""; /// <summary> /// 滚动样式设置 /// </summary> [ System.ComponentModel.Description("滚动样式设置") , System.ComponentModel.Category("滚动条设置") , System.ComponentModel.DefaultValue("") , System.ComponentModel.Bindable(System.ComponentModel.BindableSupport.Yes) ] public string ScrollCssClass { get { return _ScrollCssClass; } set { _ScrollCssClass = value; } } #region 书写标签 void WriteBeginSpan(HtmlTextWriter writer) { if (this._ShowScrollBar) { StringBuilder strSpan = new StringBuilder(); strSpan.Append("<span "); strSpan.Append(string.Format("style='overflow-y:{0};overflow-x:{1};", System.Enum.GetName(typeof(Overflow), this._OverflowY), System.Enum.GetName(typeof(Overflow), this._OverflowX))); if (this._ScrollHeight.ToString() != "0px") { strSpan.Append(string.Format("height:{0};", this._ScrollHeight)); } if (this._ScrollWidth.ToString() != "0px") { strSpan.Append(string.Format("width:{0};", this._ScrollWidth)); } strSpan.Append("';"); if (!string.IsNullOrEmpty(_ScrollCssClass)) { strSpan.Append(string.Format("", _ScrollCssClass)); } strSpan.Append(">"); writer.Write(strSpan.ToString()); } } void WriteEndSpan(HtmlTextWriter writer) { if (this._ShowScrollBar) { writer.Write("</span>"); } } #endregion #endregion
重写Render方法：
protected override void Render(HtmlTextWriter writer) { this.WriteBeginSpan(writer); base.Render(writer); this.WriteEndSpan(writer); }
就这样就可以了。
还要定义一个枚举：
public enum Overflow { auto = 0, hidden = 1, scroll = 2, visible = 3, inherit = 4 }