改编的图表控件，可以支持饼图

using System;
using System.Collections;
using System.Web.UI;
using System.Data;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Web;
using System.ComponentModel;
[ assembly: TagPrefix("WebControl", "ci") ]
namespace WebControl
{
public enum ColumniationStyle
{
histogram, beeline, caky
}
/**//// <summary>
///    柱状图控件
///    需要传入列表项名，值，超级连接地址
/// </summary>
    [ToolboxData("<{0}:Columniation runat=server></{0}:Columniation>")]
public class Columniation: System.Web.UI.WebControls.WebControl
{
private DataTable items;//列表项名称和值

private string text="实时数据";
private string datastd="标准值";
private string data="实时数据";
private ColumniationStyle _showType = ColumniationStyle.histogram;
int kds=5; //刻度数
        int kddw=100;  //没刻度大小

int zmheight=300; //真个图区高
        int zmwidth=640;  //真个图区宽

int height=250;//呈现区高
        int width=530;
int cxtop=30;//呈现区距顶距离
        int cxleft=30;//呈现区左边距离

Color bzlink=Color.Black;//标准线颜色
        Color bz=Color.Coral;//标准柱颜色
        Color ss=Color.CornflowerBlue;//实时柱颜色
//int cx=1;

[Bindable(true),Category("Appearance"),DefaultValue("")]
public string Text
{
get
{
return text;
}
set
{
text = value;
}
}
[Bindable(true),Category("Appearance"),DefaultValue("")]
public string DataStdName
{
get
{
return datastd;
}
set
{
datastd = value;
}
}
[Bindable(true),Category("Appearance"),DefaultValue("")]
public string DataName
{
get
{
return data;
}
set
{
data = value;
}
}
/**//// <summary>
/// 文本框中显示值还是名称。缺省显示值。
/// </summary>
        [Bindable(true), Category("Schema"), DefaultValue(ColumniationStyle.histogram),
Description("图表样式，默认为柱状图"), DesignOnly(true)]
public ColumniationStyle ShowType
{
get
{
return this._showType ;
}
set
{
this._showType = value;
}
}
/**//// <summary>
/// 需要呈现的数据
/// </summary>
        public DataTable Items
{
set
{items=value;}
}
/**//// <summary>
/// 需要显示的刻度量
/// </summary>
        public int Kdcount
{
set {kds=value;}
}
/**//// <summary>
/// 刻度大小
/// </summary>

public int Kddw
{set{kddw=value;}}
public ColumniationStyle ChatStyle
{set{this._showType=value;}}