如何为CheckBoxList和RadioButtonList添加滚动条

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(" class='{0}'", _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
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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