这个对象还定义了一个GetHtmlString的函数向主页面提供一个显示饼图的HTML代码。
| /// <summary> /// 创建用于显示饼图图片和超链接的HTML代码字符串 /// </summary> /// <param name="imgsrc">图片地址</param> /// <returns>创建的HTML字符串</returns> /// <remarks> /// 此处没有简单拼凑HTML字符串，而是利用XML和HTML的相似性 /// 使用一个XmlTextWriter来生成HTML字符串。 /// </remarks> public string GetHtmlString( string imgsrc ) { if( this.Count == 0 ) return ""; // 生成唯一的 map 元素名称 string name = System.Guid.NewGuid().ToString("N"); // 生成 XmlTextWriter 对象 System.IO.StringWriter myStr = new System.IO.StringWriter(); System.Xml.XmlTextWriter writer = new XmlTextWriter( myStr ); writer.IndentChar = '' '' ; writer.Indentation = 3 ; writer.Formatting = System.Xml.Formatting.Indented ; // 开始输出HTML writer.WriteStartDocument(); // 输出图片元素 writer.WriteRaw("<img src=''" + imgsrc + "'' usemap=''#" + name + "'' border=''0''/>"); // 输出 map 元素 writer.WriteStartElement("map"); writer.WriteAttributeString("name" , name ); foreach( PieShapeItem item in this ) { // 输出超链接区域 Point ps = this.GetPoints( item ); writer.WriteStartElement("area"); writer.WriteAttributeString("shape" , "poly"); writer.WriteStartAttribute("coords" , null ); for( int iCount = 0 ; iCount < ps.Length ; iCount ++ ) { writer.WriteString( ps[ iCount ].X.ToString() ); writer.WriteString("," ); writer.WriteString( ps[ iCount ].Y.ToString() ); writer.WriteString("," ); } writer.WriteEndAttribute(); if( item.Link != null && item.Link.Length > 0 ) { writer.WriteAttributeString("href" , item.Link ); } writer.WriteAttributeString("title" , item.Text ); writer.WriteEndElement(); } writer.WriteEndElement(); writer.WriteEndDocument(); writer.Close(); string html = myStr.ToString(); // 修正输出的HTML字符串 int index = html.LastIndexOf("?>"); if( index > 0 ) { html = html.Substring( index + 2 ); } return html ; } /// <summary> /// 获得包围饼图区域的点坐标数组 /// </summary> /// <param name="item">饼图项目</param> /// <returns>点坐标数组</returns> private Point GetPoints( PieShapeItem item ) { GraphicsPath path = CreatePath( item ); path.Flatten(); PointF ps = path.PathPoints ; path.Dispose(); Point ps2 = new Point[ ps.Length ] ; for( int iCount = 0 ; iCount < ps.Length ; iCount ++ ) { ps2[ iCount ].X = ( int ) ( ps[ iCount ].X ); ps2[ iCount ].Y = ( int ) ( ps[ iCount ].Y ); } return ps2 ; } |
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