我的Asp.Net页面模板算法(New)

时间：2011-05-04 来源：再快一点

/// <summary>
    /// 根据模板和一个DataTable得到一个解析字符串
    /// </summary>
    /// <param name="template">字符串模板</param>
    /// <param name="dt">一个DataTable</param>
    /// <returns>返回一个解析模板后的字符串</returns>
    public static string Render(string template, DataTable dt)
    {
        if (dt == null || dt.Rows.Count < 1)
        {
            return "";
        }
        StringBuilder sb = new StringBuilder(1000);
        List<string> arr;
        List<string> columns;
        Analyze(template, out arr, out columns);
        int i;
        foreach (DataRow row in dt.Rows)
        {
            i = 0;
            for (; i < columns.Count; i++)
            {
                sb.Append(arr[i]);
                sb.Append(row[columns[i]].ToString());
            }
            if (i < arr.Count)
            {
                sb.Append(arr[i]);
            }

        }
        return sb.ToString();
    }

    /// <summary>
    /// 根据模板和一个泛型实体集合得到一个解析字符串
    /// </summary>
    /// <typeparam name="T">实体类型</typeparam>
    /// <param name="template">字符串模板</param>
    /// <param name="list">实体集合</param>
    /// <returns>返回一个解析模板后的字符串</returns>
    public static string Render<T>(string template, List<T> list)
    {
        if (list == null || list.Count < 1)
        {
            return "";
        }
        StringBuilder sb = new StringBuilder(1000);
        List<string> arr;
        List<string> columns;
        Analyze(template, out arr, out columns);
        int i;
        Type type = typeof(T);
        foreach (T item in list)
        {
            i = 0;
            for (; i < columns.Count; i++)
            {
                sb.Append(arr[i]);
                sb.Append(GetValue(type, item, columns[i]));
            }
            if (i < arr.Count)
            {
                sb.Append(arr[i]);
            }
        }
        return sb.ToString();
    }

    /// <summary>
    /// 对一个字符串模板进行分析
    /// </summary>
    /// <param name="template">字符串模板</param>
    /// <param name="arr">存储除开列名的其他文本的集合</param>
    /// <param name="columns">存储列名的集合</param>
    static void Analyze(string template, out List<string> arr, out List<string> columns)
    {
        arr = new List<string>();
        columns = new List<string>();
        int previousEndIndex = 0;

        //找到{xxx}
        int startIndex = template.IndexOf('{');
        int endIndex = template.IndexOf('}');

        while (startIndex != -1)
        {
            //存储上一个}和现在搜索到的{之间的字符串，如果是第一次搜索到{，那么previousEndIndex=0则存储的是字符串起始到第一个{之间的字符串
            arr.Add(template.Substring(previousEndIndex, startIndex - previousEndIndex));
            //存储列名
            columns.Add(template.Substring(startIndex + 1, endIndex - startIndex - 1));

            startIndex++;
            endIndex++;
            previousEndIndex = endIndex;

            startIndex = template.IndexOf('{', startIndex);
            endIndex = template.IndexOf('}', endIndex);
        }

        //如果模板不是以}结尾，说明后面还有字符串
        if (previousEndIndex < template.Length)
        {
            arr.Add(template.Substring(previousEndIndex));
        }
        //方法执行到此处，arr.Length==columns.Length或者arr.Length==columns.Length+1
    }

    /// <summary>
    /// 根据一个实体类型，实体实例和属性名，获取属性值
    /// </summary>
    /// <param name="type">实体类型</param>
    /// <param name="item">实体实例</param>
    /// <param name="attrName">属性吗</param>
    /// <returns></returns>
    static string GetValue(Type type, object item, string attrName)
    {
        PropertyInfo property = type.GetProperty(attrName, BindingFlags.Public | BindingFlags.IgnoreCase | BindingFlags.Instance);
        object obj = property.GetValue(item, null);
        if (obj != null)
        {
            return obj.ToString();
        }
        return "";
    }

/// <summary>
    /// 根据模板，使用正则匹配然后替换输出字符串
    /// </summary>
    /// <param name="template"></param>
    /// <param name="dt"></param>
    /// <returns></returns>
    public static string RenderTemplate(string template, DataTable dt)
    {
        StringBuilder sb = new StringBuilder(1000);
        MatchCollection matches = reg.Matches(template);
        string rowStr = template;
        foreach (DataRow row in dt.Rows)
        {
            rowStr = template;
            foreach (Match match in matches)
            {
                rowStr = rowStr.Replace(match.Value, row[match.Groups[1].Value].ToString());
            }
            sb.Append(rowStr);
            sb.Append("\n");
        }
        return sb.ToString();

    }